## Marvin and Milo

Enrichment Activity for 5-11 11-14

Here  you can browse the entire back catalogue of Marvin and Milo physics activities. You can also now search the Marvin and Milo collection by physics terms.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Straw Water Gun

Pressure
Properties of Matter

## Straw Water Gun

At home for 5-11 11-14

#### What you need

• A drinking straw
• A friend
• A ruler
• Scissors
• Sticky tape
• Saucer of water

#### Instructions

1. The challenge is to lift the water from the saucer using a straw but without sucking
2. Get your ruler and cut your drinking straw into two pieces: one 3cm long and one 5cm long
3. Join the pieces together with sticky tape along one side so they form a 90 degree angle, but leave both ends open
4. Stand the smaller end of the straw in the saucer of water
5. Now blow hard!

#### Results and Explanation

When air moves, its pressure falls. So when you blow, the pressure at the top of the straw drops. But the air over the saucer keeps the same pressure, so the water is pushed up the straw.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Forceful Comb

Charge
Electricity and Magnetism

## Forceful Comb

At home for 5-11 11-14

• A nylon comb
• A water tap

#### Instructions

1. Turn on the tap until you have a very thin stream of water
3. Run the comb through your hair several times
4. Slowly bring the comb towards the water, 10cm below the tap

#### Results and Explanation

When the comb is about 3cm away, the water bends towards it! Some objects, like hair and plastic, develop an electrical charge when rubbed together.

The charge in your comb attracts tiny electrical charges in the water molecules, pulling them towards it.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Soap Sculptures

Pressure
Properties of Matter

## Soap Sculptures

At home for 5-11 11-14

#### What you need

• A microwave
• A bar of quality soap

#### Instructions

1. Put the soap on a dish in the microwave
2. Heat it on full power for about 1 minute
3. WARNING: The soap may smell strongly so don't do this before heating food

#### Results and Explanation

Tiny pockets of gas in the soap expand in all directions, pushing the soap into strange and artistic shapes.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Spinning Eggs

Force
Forces and Motion

## Spinning Eggs

At home for 5-11 11-14

#### What you need

• A raw egg
• A hard-boiled egg

#### Instructions

1. First spin the hard-boiled egg
2. Stop it and let go immediately
3. Watch what happens
4. Now spin the raw egg
5. Stop it and let it go immediately

#### Results and Explanation

The egg starts spinning! The yolk and the white aren't attached to the shell so they carry on moving when you stop the raw egg. Get a friend to mix up the eggs and use the trick to tell them apart.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Sew an Ice Cube

Phase Change
Properties of Matter

## Sew an Ice Cube

At home for 5-11 11-14

#### What you need

• Salt
• A cup of cold water
• An ice cube

#### Instructions

1. Float the ice cube in the cup of water
2. Lay one end of the thread (or a loop) on top of the ice cube
3. Sprinkle a little salt over the top
4. Wait one minute then gently lift the thread

#### Results and Explanation

Salt lowers the melting point of water so the ice melts. But the water quickly refreezes, trapping the string in place.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Lava Lamp

Upthrust
Properties of Matter

## Lava Lamp

At home for 5-11 11-14

#### What you need

• A large glass
• Peanuts (or raisins)

#### Instructions

1. Fill the glass with lemonade
2. Stir for 1 min or leave to go slightly flat
3. Drop some peanuts into the glass

#### Results and Explanation

The nuts float up to the top and fall back down again, like in a lava lamp. Gas bubbles grow on the peanuts, making them float upwards. When they reach the top the bubbles burst and the peanuts fall back down again.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Magic Balloon

Pressure
Properties of Matter

## Magic Balloon

At home for 5-11 11-14

#### What you need

• A clear plastic bottle
• A pen
• A balloon (blow it up a few times beforehand)

#### Instructions

1. Make a hole in the bottom of the bottle with the pen
2. Push the balloon inside and stretch it over the mouth
3. Blow up the balloon
4. Notice air is coming out of the hole in the bottle
5. Cover the hole with your finger and stop blowing

#### Results and Explanation

The balloon stays inflated! As the balloon expanded, it pushed air out of the bottle. That made the pressure inside the bottle lower than the pressure inside the balloon, so it wasn't strong enough to squeeze the air out.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Musical Coat Hanger

Sound Wave
Light Sound and Waves

## Musical Coat Hanger

At home for 5-11 11-14

#### What you need

• A metal coat hanger
• Two pieces of string
• A fork

#### Instructions

1. Tie a piece of string to each corner of the coat hanger and wrap the ends around your fingers

#### Results and Explanation

It sounds louder because vibrations travel through the metal and string more easily than through air.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Alka-Seltzer Rocket

Pressure
Properties of Matter

## Alka-Seltzer Rocket

At home for 5-11 11-14

#### What you need

• An Alka-Seltzer tablet
• An empty film canister
• Old newspaper
• Water

#### Instructions

1. Put the tablet in the film canister. Add about 1cm of water
2. Put the lid on, lightly shake the canister
3. Quickly place it upside down on the newspaper and stand back!

#### Results and Explanation

The Alka-Seltzer fizzes when in water, releasing gas. This gas builds up in the canister until the pressure is too great and the lid is forced off!

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Magic Toothpicks

Force
Properties of Matter

## Magic Toothpicks

At home for 5-11 11-14

#### What you need

• Five wooden toothpicks
• A small sponge
• A plate
• A little water

#### Instructions

1. Snap the toothpicks in half but don't break them fully
2. Arrange the toothpicks on the plate so they are spaced out with their broken ends forming a small circle
3. Carefully squeeze a drop of water into the middle. Make sure it touches the end of each toothpick

#### Results and Explanation

The toothpicks move. Just like synchronised swimmers! The water makes the wood expand, the broken ends press against each other and the toothpick opens out. The same thing happens to doors when it's humid - they swell and get jammed.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Wobbly Stick

Mass
Forces and Motion

## Wobbly Stick

At home for 5-11 11-14

#### What you need

• A stick (1m long)
• A lump of clay

#### Instructions

1. Push a lump of clay about the size of your fist on to the stick 20cm from the end
2. With the clay-end closest to your hand, try balancing the stick
3. Now turn the stick upside down and try balancing it again

#### Results and Explanation

It's much easier to balance it the second way. The stick rotates slower when the clay is at the top, so there's more time to adjust and keep it balanced. The further the mass is from the centre of rotation (your hand), the slower it rotates.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Foil Boat

Surface Tension
Properties of Matter

## Foil Boat

At home for 5-11 11-14

#### What you need

• A piece of foil
• Scissors
• Washing-up liquid
• A sink or bath

#### Instructions

1. Take your foil and cut a shape 4cm x 10cm. The shape should look like a house (or rectangle with a triangle on top) with the base of the house being the shortest side. From the base cut a slot with a circle on the top.
2. Gently place your boat into a sink full of clean water.
3. Carefully place a drop of washing-up liquid into the boat's hole.

#### Results and Explanation

The boat moves! Water molecules are attracted to each other, creating "surface tension". The soap disrupts the surface behind the boat but the molecules in front are still pulling together, so the boat is pulled forward.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### TV Strobe Light

Oscillating String
Light Sound and Waves

## TV Strobe Light

At home for 5-11 11-14

#### What you need

• A cathode ray tube television (turned on!)
• A rubber band

#### Instructions

1. Stretch the rubber band between your thumb and first finger
2. Holding the band between you and the television screen, pluck one side

#### Results and Explanation

You should see the band make zig zag shapes. The television picture is made up of tiny dots flashing on and off. It acts like a strobe light, freezing the band's vibrations at different positions so it looks like it's moving in slow motion.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Collapsing Bottle

Pressure
Properties of Matter

## Collapsing Bottle

At home for 5-11 11-14

#### What you need

• A plastic bottle
• Some hot water

#### Instructions

1. Very carefully pour a little hot water into the bottle, or ask a grown-up to help
2. Shake the bottle
3. Pour out the water
4. Put the lid on, put the bottle down and wait a few minutes

#### Results and Explanation

The hot water raises the temperature - the pressure increases and the molecules spread out (some leave the bottle). When the air cools, the pressure is lower than before because there are fewer molecules bouncing around. The air pushing on the outside of the bottle has more pressure, which crushes the bottle.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Convection Snake

Convective Heating
Properties of Matter

## Convection Snake

At home for 5-11 11-14

#### What you need

• A sheet of paper
• Scissors

#### Instructions

1. Cut a thick spiral shape in the piece of paper
2. Make a hole in the centre and thread the cotton through it
3. Hang the spiral above the radiator

#### Results and Explanation

The spiral should start to spin slowly. The radiator raises the temperature of the air around it, so the particles move more quickly and spread out. This means the air is less dense and rises upwards. The rising air pushes on the paper causing it to spin.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bouncing Balls

Momentum
Forces and Motion

## Bouncing Balls

At home for 5-11 11-14

#### What you need

• A tennis ball
• A room without breakables

#### Instructions

1. Drop the tennis ball from waist height and see how high it bounces
2. Drop the basketball from the same height and see how high it bounces
3. Put the tennis ball on top of the basketball and drop them both at arms length from waist height

#### Results and Explanation

The tennis ball should bounce a lot higher than before. When the balls hit the ground, momentum from the basketball was transferred to the tennis ball making it go much higher than before.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Reversing Glass

Lens
Light Sound and Waves

## Reversing Glass

At home for 5-11 11-14

#### What you need

• A glass of water
• A piece of paper
• A marker pen

#### Instructions

1. Draw a column of short arrows
2. Hold the paper a little way behind the glass and look through the water at the arrows

#### Results and Explanation

The arrows should point in the opposite direction. The water acts like a glass lens, bending the rays of light and reversing the image of the arrows.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Juice Carton Sprinkler

Newtons Third Law
Forces and Motion

## Juice Carton Sprinkler

At home for 5-11 11-14

#### What you need

• An empty juice carton
• A piece of string
• A pair of scissors
• A washing-up bowl
• Water

#### Instructions

1. Get an adult to poke a hole in the bottom left-hand corner of each face of the carton
2. Poke another hole in the top flap and thread the string through it
3. Put some water in the bowl, stand the carton in it, then fill it up to the top
4. Lift the carton out by the string

#### Results and Explanation

As the water shoots out it pushes back on the carton with an equal force. Because the holes are off-centre this force makes it spin around.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Balloon Rocket

Newtons Third Law
Forces and Motion

## Balloon Rocket

At home for 5-11 11-14

#### What you need

• A drinking straw - cut in half
• A balloon
• A long piece of string
• A clothes peg
• Sticky tape

#### Instructions

1. Blow up the balloon and peg the neck to keep the air in
2. Thread the straw with the string and then tape it lengthways to the balloon
3. Tie the string across the room
4. Now unclip the peg!

#### Results and Explanation

As the air rushes out it pushes back on the balloon propelling it forward.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Melting Race

Phase Change
Properties of Matter

## Melting Race

At home for 5-11 11-14

#### What you need

• A plastic container
• A metal frying pan
• 2 identical ice cubes

#### Instructions

1. Place the frying pan and the container upside down next to each other
2. Quickly put an ice cube on each

#### Results and Explanation

Heat can flow through the metal to the ice cube, but the plastic doesn't allow it to flow so freely.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Simple Siphon

Potential Energy
Energy and Thermal Physics

## Simple Siphon

At home for 5-11 11-14

#### What you need

• A bendy straw
• Water
• Two small flat bowls
• Food colouring

#### Instructions

1. Fill one bowl with water and a little food colouring
2. Half fill the second bowl
3. Submerge the straw in water, making sure you get rid of any air bubbles, and tightly pinch the ends of the straw before you pull it out
4. Hold the straw with one end in each bowl, and release the ends when they're under the water

#### Results and Explanation

The water in the bowl with the higher water level is under greater pressure, and so water moves through the straw to the lower level.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Impossible Straws

Atmospheric Pressure
Properties of Matter

## Impossible Straws

At home for 5-11 11-14

#### What you need

• Three straws
• A glass of drinking water
• A drawing pin (for making a small hole in one of the straws)

#### Instructions

1. Bet your friend that they can't suck up any of the water with two straws in their mouth
2. The catch is that they have to have one straw outside of the glass, and one inside. What happens?
3. Make a small hole 3 cm from the top of the other straw
4. What happens when your friend tries to suck water using just this straw?

#### Results and Explanation

It's impossible to suck water through the straws. In order for the water to be forced into your mouth, the pressure outside your mouth (atmospheric pressure) needs to be greater than the pressure inside. This means that no matter how you suck, a straw won't work if air can get into your mouth.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Stringy Water

Friction
Forces and Motion

## Stringy Water

At home for 5-11 11-14

#### What you need

• A jug of water
• A basin or sink

#### Instructions

1. Tie the string around the handle of the jug and pull it across the top and over the lip
2. Hold the string tight at an angle, below the jug, and begin to pour

#### Results and Explanation

The water flows along the string. The friction between the string and the water slows down the flow, pulling the water to the string and making it stick to it. Try creating an amazing route for the water by holding the string at different angles, even getting the water to turn corners as it goes down. But be careful, no sharp turns or the water falls off!

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Water Jets

Surface Tension
Properties of Matter

## Water Jets

At home for 5-11 11-14

#### What you need

• Small plastic drinks bottle
• Some water
• Drawing pin

#### Instructions

1. Use the drawing pin to make three small holes about 4mm apart at the bottom of the bottle and one near the neck
2. Fill the bottle with water and put the top on (tip: cover up the top hole to stop the water shooting out of the bottom three)
3. With the top hole uncovered, three water jets will shoot out of the bottom holes. What happens when you smear the jets together with your thumb, near the holes?

#### Results and Explanation

Once the jets have been smeared together they stay together due to surface tension.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Indestructible Bag

Force
Properties of Matter

## Indestructible Bag

At home for 5-11 11-14

#### What you need

• Water
• Clear plastic watertight bag (e.g. watertight, resealable food bag)
• Some pencils

#### Instructions

1. Fill the plastic bag with water
2. Push a pencil through the bag
3. Then another... and another

#### Results and Explanation

The bag doesn't burst because the plastic stretches rather than tears as the pencils are pushed through it. If you take a pencil out you can plug the leak simply by putting it back through the holes.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Magic Apples

Atmospheric Pressure
Properties of Matter

## Magic Apples

At home for 5-11 11-14

#### What you need

• Two apples with stalks
• Two pieces of string about 30cm long
• Some sticky tape

#### Instructions

1. Tie a piece of string to the stalk of each apple
2. Use the tape to hang up the two apples so that they are about 6cm apart and free to swing
3. Blow hard between the apples. What happens?

#### Results and Explanation

The apples move toward each other. Blowing reduces the air pressure in the gap between the apples. The air pushing on the outer sides of the apples makes them move into the area of lower pressure, so they move towards each other.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Singing Paperclip Trick

Resonance
Light Sound and Waves

## Singing Paperclip Trick

At home for 5-11 11-14

#### What you need

• A paperclip
• Water
• Two identical glasses
• Marvin bets Milo that he can make the paperclip move without touching it

#### Instructions

1. Put equal amounts of water in both glasses and stand them next to each other but not touching
2. Straighten out the paperclip into a straight wire, then bend it slightly (it should be shaped more-or-less like a boomerang), Balance it on the rim of one of the glasses
3. With a wet finger, rub around the rim of the other glass until it "sings"
4. The paperclip moves!

#### Results and Explanation

Rubbing the glass makes it vibrate at its natural frequency. Because the other glass is identical it has the same natural frequency and the sound waves from the other glass make it vibrate as well - so the paperclip moves.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Chicken Sounds

Sound Wave
Light Sound and Waves

## Chicken Sounds

At home for 5-11 11-14

#### What you need

• A plastic cup or yoghurt pot
• A damp cloth
• Smooth string
• Pencil or biro

#### Instructions

1. Make a hole in the bottom of a plastic cup with a pencil or biro
2. Cut a length of string, thread it through the hole, and tie a knot in the end inside the cup to stop it from slipping back through the hole
3. Take the damp cloth and hold it tightly around the string. Now pull the cloth firmly along the string to hear the cup cluck

#### Results and Explanation

Pulling the cloth along the string makes it vibrate and produce a faint sound. But the cup and air around it also vibrate so the sound is amplified enough for us to hear it.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Cartesian Ketchup Sachet Diver

Density
Properties of Matter

## Cartesian Ketchup Sachet Diver

At home for 5-11 11-14

#### What you need

• 2 litre plastic bottle
• Blue Tac
• A bowl of water
• A ketchup sachet

#### Instructions

1. Put the ketchup sachet into a bowl of water to see if it floats upright - if not then add a little Blue Tac to its bottom
2. Fill the 2 litre bottle with water right to the top
3. Push your ketchup diver through the neck of the bottle
4. Put the lid on tightly, squeeze the bottle hard and watch your diver dive

#### Results and Explanation

The diver sinks when you squeeze the bottle, and rises when you let go.

Tip: if you diver doesn't dive, or sinks without rising, change the amount of Blue Tac on the sachet.

Squeezing the bottle squeezes everything inside it, including the air bubbles in the ketchup sachet. As the air molecules squash together, the sachet gets more dense than the water and it sinks. What happens when you stop squeezing?

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Inseparable Books

Friction
Forces and Motion

## Inseparable Books

At home for 5-11 11-14

#### What you need

• Two very similar books, with at least 100 pages each

#### Instructions

1. Carefully, and evenly, interweave the pages of the books son that they overlap to about the middle of the page
2. Hold the books by the spines and pull!

#### Results and Explanation

Friction is the force that acts against the motion of two surfaces in contact. The friction between the just two pages is tiny, but with lots of pages in the books, the force becomes very noticeable.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Dancing Pop Can

Mass
Forces and Motion

## Dancing Pop Can

At home for 5-11 11-14

#### What you need

• An empty fizzy drink can
• Some water

#### Instructions

1. Pour about 100ml of water into an empty fizzy pop can
2. Tip it slightly to one side and balance it so that the two parts of the bottom rim are touching the table
3. Once the can is stable, give it a gentle push and it will pirouette!

#### Results and Explanation

For something to balance, its centre of mass has to be above its point of support. Water can flow which means that as the can pirouettes, the water moves and the centre of mass always stays above where the rim touches the table.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Up next

Seasonal Change
Earth and Space

At home for 5-11 11-14

#### What you need

• A large clear, straight-sided glass
• Water
• Milk
• Teaspoon
• Torch
• Darkened room

#### Instructions

1. Fill the glass about two thirds full of water
2. Add half a teaspoon of milk and stir
3. In a darkened room, shine the torch down onto the top of the water while looking through the side of the glass. Can you see the blue colour?
4. Now try shining the torch through the side of the glass while looking through the opposite side. What colours can you see now?
5. Finally, shine the torch up through the bottom of the glass and peer down through the water

#### Results and Explanation

While shining the light up through the bottom of the glass, you should see a 'homemade sunset'. The milk particles in the glass scatter the light in the same way that dust and particles in the Earth's atmosphere scatter light from the sun. The further the light has to travel through the water, the more of the blue light is scattered, leaving only red light for you to see, just like at sunset.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Gripping Rice

Friction
Forces and Motion

## Gripping Rice

At home for 5-11 11-14

#### What you need

• Uncooked rice
• A pencil
• A large empty jar with a narrow neck

#### Instructions

1. Fill the jar to the brim with uncooked rice (make sure you have a jar that narrows towards the top)
2. Push the pencil right into the rice
3. Stab the rice repeatedly, alternating between shallow and deep stabs. It could take up to 40 stabs, but you'll start to feel the pencil gripping the rice
4. When you feel a firm grip, carefully lift the jar by the pencil

#### Results and Explanation

The pencil lifts the jar. As you push it in, the pencil forces the grains sideways, but they fall back into the gap as you try to pull it out. The rice becomes more and more tightly packed until the friction between the rice and the pencil is so great you can lift the jar.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Cup Trick

Atmospheric Pressure
Properties of Matter

## Cup Trick

Enrichment Activity for 5-11 11-14

#### What you need

• Two identical paper or plastic cups

#### Instructions

1. Take two empty cups and put one inside the other
2. Hold them quite close to your mouth and blow between the rims of the cups

#### Results and Explanation

If you blow softly the inner cup rises up slowly. If you blow hard the top cup launches itself across the room.
Moving air has a lower pressure than still air, so, as you blow, you lower the air pressure between the rims. As the still air in the bottom of the cup is at a higher pressure, it forces the top cup up and out.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### DIY Chromatography

Diffusion
Properties of Matter

## DIY Chromatography

At home for 5-11 11-14

#### What you need

• Kitchen towels
• Water
• Non-permanent coloured felt tip pens

#### Instructions

1. Draw a dot in the centre of the kitchen towel with a felt tip pen. Black works well, but you can experiment with other colours
2. Add a few drops of water to the dot

#### Results and Explanation

As the water spreads through the tissue, the coloured pigments that make up the ink separate out.
The differently coloured pigments are made up of different-sized molecules. This means that the water can carry them different distances across the paper.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### On a Roll

Charge
Electricity and Magnetism

## On a Roll

At home for 5-11 11-14

#### What you need

• A balloon
• An empty pop can (aluminium cans are best)

#### Instructions

1. Tell your friend you can make the can roll along without touching it or blowing it
2. Place the can on its side on a flat surface
3. Rub the balloon really fast against your hair or a woolly jumper
4. Hold the balloon close to the can - the can will start moving towards the balloon
5. Slowly move the balloon away from the can and the can will follow it

#### Results and Explanation

When you rub the balloon against your hair, electrons are transferred from your hair to the surface of the balloon, so that it becomes negatively charged.
When you hold the balloon close to the can the negative charge causes the electrons in the can to move away (they are repulsed by the negative charge, because they are negatively charged themselves). This creates a positive charge on the surface of the can, so that now the can is attracted towards the negative charge on the balloon.
This trick works well with a pop can because it's light, so it will move with a small force applied to it, and because in a metal it is easier for electrons to move around.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Clumsy Catching

Formation of Images
Light Sound and Waves

## Clumsy Catching

At home for 5-11 11-14

#### What you need

• A cone shaped party hat
• Scissors
• A soft ball
• A friend

#### Instructions

1. Cut the tip off the party hat to make a hole about 2cm in diameter
2. Wear the hat over your face
3. Try to play catch with your friend using a soft ball

#### Results and Explanation

When you’re wearing the hat you can only see with one eye at a time. Without your normal, two-eyed, binocular vision you can’t judge distances as well and it’s much harder to catch the ball.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Festive Star

Phase Change
Properties of Matter

## Festive Star

Enrichment Activity for 5-11 11-14

#### What you need

• Large glass of hot water

• Pencil
• Two pipe cleaners
• Epsom salts
• Blue food colouring
• Spoon

#### Instructions

1. Cut one pipe cleaner in half. Twist the two halves around the second pipe cleaner to make a six pointed star.
2. Twist the long point around a pencil so the star can hang from it.
3. Fill a class with enough hot water so that the star will be completely covered when it's hanging from the pencil.
4. Add some colouring to the water.
5. Stirring, add epsom salts to the water until no more will dissolve and wait overnight.
6. Hang the star in the water and wait overnight.

#### Results and Explanation

A sparkly star emerges.

The rough surface of the pipe cleaners acts as a nucleation site, encouraging the salt molecules to come out of solution and form crystals. They grow overnight as more and more salt molecules attach to the crystal surfaces.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Loop the Loop

Force
Forces and Motion

## Loop the Loop

Enrichment Activity for 5-11 11-14

#### What you need

• Two polystyrene cups
• Two large elastic bands
• Sticky tape

#### Instructions

1. Tape the two polystyrene cups together at the base
2. Tie the two elastic bands together
3. Hold one end of the elastic where the cups join and wind it around a few times until the other end of the elastic is at the bottom and pointing away from you
4. Hold the cups in one hand and stretch the elastic with the other
5. Fire the cups like a catapult

#### Results and Explanation

Once you've had a bit of practice, the cups will soon be looping in the air.
This is because elastic makes the cups spin backwards as well as move forward through the air. This back spin creates lift, forcing the cups upwards. But air resistance soon slows the cups down and they fall towards the ground, completing the loop.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Daredevil Egg

Inertia
Forces and Motion

## Daredevil Egg

At home for 5-11 11-14

#### What you need

• An egg
• A glass of water
• An empty Smarties tube
• A placemat

#### Instructions

1. Put the placemat on top of the glass of water, shiny side down
2. Stand the Smarties tube on the placemat directly over the glass and balance the egg on top of the tube
3. Give the side of the placemat a short, sharp, horizontal whack

#### Results and Explanation

The egg doesn’t go flying because the sideways force is only on the mat and the bottom of the tube, not the egg.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Spinning Rocket

Newtons Third Law
Forces and Motion

## Spinning Rocket

At home for 5-11 11-14

#### What you need

• Pencil with a rubber on the end
• Drawing pin
• Drinking straw
• Sticky tape

#### Instructions

1. Insert the long end of the straw into the balloon and tape it in place
2. Push the drawing pin through any part of the long end of the straw to attach it to the pencil’s rubber.Bend the short end
3. Blow up the balloon using the straw, release, and watch it spin!
4. Try changing the position of the drawing pin and the angle of the short end to make it spin faster

#### Results and Explanation

The air rushes along the straw and around the bend. As the straw pushes on the air to force it round the corner, the air pushes back on the straw; making it move.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Antigravity Maltesers

Circular Motion
Forces and Motion

## Antigravity Maltesers

At home for 5-11 11-14

#### What you need

• A wine glass (narrower towards the top)
• A Malteser

#### Instructions

1. Put the Malteser on the table and place the glass over it
2. Wiggle the glass quickly with a circular motion and the Malteser will start to climb the sides of the glass
3. Keeping wiggling, lift the glass off the table and the Malteser will stay inside!

#### Results and Explanation

The glass pushes inwards on the Malteser, forcing it to move in a circle rather than a straight line. But the angle of the glass means that it also pushes upwards on the Malteser, supporting its weight.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Loud Lollies

Sound Wave
Light Sound and Waves

## Loud Lollies

At home for 5-11 11-14

#### What you need

• 2 lolly sticks
• A wide elastic band
• 2 smaller, narrower elastic bands
• A straw
• Scissors

#### Instructions

1. Wrap the wide elastic band lengthwise around one of the sticks
2. Cut two short pieces of straw and place them in between the stick and elastic band - one about 3cm from each end of the stick
3. Place the other stick on top of the pieces of straw. Hold the ends of both sticks together with the smaller elastic bands
4. Then blow! What happens if you move the straws closer together?

#### Results and Explanation

Blowing through the Loud Lollies makes the elastic band vibrate and create a sound. Moving the straws closer together shortens the section of the elastic band that can vibrate, raising the pitch of the sound produced.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Hovercrafty

Friction
Forces and Motion

## Hovercrafty

At home for 5-11 11-14

#### What you need

• An old CD
• A sports cap from a drinks bottle
• Blu Tack
• A balloon

#### Instructions

1. Place the sports cap in the centre of the cd and fix it in place with the Blu Tack
2. Blow up the balloon and, making sure the sports cap is closed, pull the open end of the balloon over the cap
3. Place your hovercraft on a flat surface and open the sports cap. Give it a quick tap and watch your hovercraft go!

#### Results and Explanation

The air rushes out of the balloon and through the cap, lifting the CD up on a cushion of air. The air reduces the friction between the CD and surface it’s on so the hovercraft can travel a surprising distance before stopping.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Uphill Biscuit Tin

Levers
Forces and Motion

## Uphill Biscuit Tin

At home for 5-11 11-14

#### What you need

• A round biscuit tin (or similar container)
• A ramp or slope
• A lump of plasticine

#### Instructions

1. Attach a large-fist-sized lump of plasticine to the inside of the wall of the tin at the seam and put the lid on
2. With the seam facing upwards but towards the top of the slope, put the tin on its side at the bottom of the slope and hold it in place
3. Let go

#### Results and Explanation

The weight of the plasticine creates a turning force on the tin that levers it up the hill when you let go, and makes it look as though you're defying gravity.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Key Drop

Angular Velocity
Forces and Motion

## Key Drop

At home for 5-11 11-14

#### What you need

• A bunch of about 3 keys
• A large paperclip or washer
• A pencil
• 1m of string

#### Instructions

1. Tie the bunch of keys to one end of the string and the paperclip to the other
2. Place the string over the pencil so that the keys hang down a couple of centimetres
3. Hold the paperclip horizontally out to the other side
4. Let go of the paperclip

#### Results and Explanation

The paperclip winds around the pencil and stops the keys hitting the floor!
This is because the keys pull the paperclip towards the pencil, but gravity is also pulling it downwards so it moves in a circle. As the paperclip gets closer to the pencil, its angular velocity increases, and it wraps around the pencil.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Dry Dive

Atmospheric Pressure
Properties of Matter

## Dry Dive

At home for 5-11 11-14

• A bowl
• A glass
• Water
• A tissue

#### Instructions

1. Fill the bowl with enough water to completely cover the glass
2. Scrunch up the tissue and push it into the bottom of the glass
3. Turn the glass upside down and submerge it in the water

#### Results and Explanation

Pull the glass out and the tissue is…Dry!

The air trapped inside the mug is at atmospheric pressure and this keeps the water out of the mug and away from the tissue.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bubble Race

Properties of Matter

## Bubble Race

At home for 5-11 11-14

• Two glasses
• Skimmed milk
• Whole milk
• Two straws
• A friend

#### Instructions

1. Pour about five centimetres of skimmed milk in to one glass and the same amount of whole milk in to the other glass
2. Both starting at the same time, blow through the straws and into the milk

#### Results and Explanation

The skimmed milk froths up much faster than the whole milk, and the bubbles last longer too!
Bubbles can form in milk because the milk proteins form a strong skin. But the fat in whole milk interacts with these proteins, weakening this skin and popping the bubbles.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Up next

Inertia
Forces and Motion

At home for 5-11 11-14

#### What you need

• A metal clothes hanger
• Plasticine

#### Instructions

1. Straighten out the clothes hanger and then bend it into an ‘M’ shape with long ‘legs’
2. Make two equal-sized Plasticine balls and stick them on to the legs of the M
3. Balance the hanger on your head with the Plasticine balls well away from your ears. This might take some practice
4. Spin round quickly. (Be careful of the ends of the hanger and your face)

#### Results and Explanation

As you turn, the hanger remains almost stationary! The friction between your head and the wire is very low so the hanger doesn’t move with you.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Glowing

Charge
Electricity and Magnetism

## Glowing

At home for 5-11 11-14

#### What you need

• An envelope
• A Polo mint or similar sugary sweet
• Roll of sticky tape
• A dark room
• A friend or mirror

#### Instructions

1. Wait about five minutes in a dark room so that your eyes become dark adapted and you can make out some objects
2. Rip open the seal of the envelope – you will see a bluish glow
3. Try crunching a sweet with your mouth open or ripping a piece of sticky tape off the roll

#### Results and Explanation

Cracking sugar or ripping apart glued surfaces separates positive and negative electrical charges. When they recombine the surrounding air is excited, producing flash of bluish light.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Water Fall

Gravitational Force (Weight)
Forces and Motion

## Water Fall

At home for 5-11 11-14

#### What you need

• A plastic cup
• A pair of scissors
• Some water

#### Instructions

1. Cut a hole in the bottom of the plastic cup about 1cm in diameter, making sure that your finger can cover it (ask an adult to help with this)
2. Cover the hole with your finger and fill the cup with water. Make sure you’re somewhere that can get wet
3. Drop the cup, removing your finger from the hole as quickly as possible

#### Results and Explanation

The water stays inside the cup despite the huge hole! The cup and the water are falling at the same rate due to gravity so they hit the ground at the same time.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bottle Blast

Force
Forces and Motion

## Bottle Blast

At home for 5-11 11-14

#### What you need

• An empty plastic bottle
• A balloon
• Scissors
• Sticky tape
• A target

#### Instructions

1. Carefully cut the bottom of the bottle off. Cut the neck off the balloon
2. Stretch the balloon over the bottom of the bottle. Don’t pull it tight
3. Tape the balloon in place around the bottle
4. Take aim at your target, pull back the centre of the balloon, hold the bottle steady and release!

#### Results and Explanation

A vortex of air is pushed out of the bottle by the balloon, ruffling everything it passes. How far will the vortex travel?

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Quiche Lightning

Charge
Electricity and Magnetism

## Quiche Lightning

At home for 5-11 11-14

#### What you need

• A piece of polystyrene
• A clean foil quiche tin
• A drawing pin
• A pencil with a rubber end
• A woollen glove

#### Instructions

1. Push the drawing pin through the centre of the foil tin and push the rubber end of the pencil on to it to form a handle
2. Rub the polystyrene quickly with the glove
3. Using the pencil handle, put the foil tin on top of the polystyrene. Don’t touch the foil or the polystyrene
4. Bring an outstretched finger close to the tin and see what happens

#### Results and Explanation

You should hear, feel and maybe even see a tiny spark!
Rubbing the polystyrene makes it negatively charged. This excess charge repels the electrons in the foil. Your finger provides an escape route for the electrons in the foil and as they jump the gap you get a small electric shock.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Doppler Spin

Doppler Shift
Light Sound and Waves

## Doppler Spin

At home for 5-11 11-14

#### What you need

• A buzzing egg timer
• A piece of string ~1 m
• Sticky tape
• A friend

#### Instructions

1. Tie the piece of string to the egg timer securely, using some sticky tape as well if needed
2. With the timer buzzing, hold the other end of the string very tightly and start to swing it in a circle around your head. Make sure your friend is standing well back and there’s nothing breakable near you

#### Results and Explanation

Your friend will hear the pitch of the egg timer change as it moves around your head - but you won’t hear any change at all!
As the egg timer circles towards your friend, the sound waves bunch up closer together and the pitch of the sound gets higher. As it circles away, the sound waves spread out and the pitch becomes lower.  Your position relative to the egg timer is always the same so you don’t hear any difference.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Wobbler

Mass
Forces and Motion

## Wobbler

At home for 5-11 11-14

#### What you need

• Bouncy ball or ball of Plasticine
• Piece of paper
• Sticky tape
• Scissors

#### Instructions

1. Cut the bouncy ball in half
2. Roll the paper into a column around the top of the ball and hold it in place with sticky tape
3. If you flick the column of paper, it will fall over.  Cut off bits of paper until when you flick it, it rights itself again

#### Results and Explanation

The wobbler is self-righting because its centre of mass is very low. As the wobbler leans over, its centre of mass rises but gravity pulls the wobbler back upright before it can topple over.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Light Fantastic

Charge
Electricity and Magnetism

## Light Fantastic

At home for 5-11 11-14

#### What you need

• Party balloon
• Energy saving light bulb

#### Instructions

1. Blow up the balloon and tie the end
2. In a dark room, rub the balloon against your hair or jumper
3. Hold the bulb in one hand and move the balloon back and forth close to it

#### Results and Explanation

Waving the electrically charged balloon close to the bulb causes a current to flow through the charged gas inside the bulb and it lights.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Glass Lift

Atmospheric Pressure
Properties of Matter

## Glass Lift

At home for 5-11 11-14

#### What you need

• Two plastic glasses
• Paper towel
• Hot water
• Sink

#### Instructions

1. Fill both glasses about 1/3 full with hot water. Carefully swirl the water around one of the glasses and pour the water away - mind not to splash yourself
2. Dampen the paper towel and place it over the empty glass. Swirl and empty the second glass and place it upside down on top of the first
3. Hold the top glass in place for ~20 seconds; then use the top glass to pick up both glasses

#### Results and Explanation

The hot water heats up the air inside the glasses, which expands and some escapes. With the two glasses held together the escaped air can’t get back in as the air inside cools and shrinks. This means that the air pressure outside the glasses is higher than inside and the glasses are pushed tightly together.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Eggstrordinary

Force
Forces and Motion

## Eggstrordinary

At home for 5-11 11-14

#### What you need

• Raw egg
• Large pop bottle
• Scissors
• Sticky tape
• Water
• Salt

#### Instructions

1. Cut the top off the bottle and put the egg inside
2. Fill the bottle with enough water so that the egg is well covered. Add salt to the water, stirring, until the egg floats
3. Tape the top of the bottle back on. Drop the bottle to the floor from waist height

#### Results and Explanation

The egg doesn’t break because the salt water spreads the impact across the whole egg. Try dropping the egg in the bottle without the salt water.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Electric Dill

Charge
Electricity and Magnetism

## Electric Dill

At home for 5-11

#### What you need

• A saucer
• Vegetable oil
• Dried dill
• Balloon

#### Instructions

1. Pour the vegetable oil into the saucer so it’s about 0.5 cm deep and sprinkle the dill liberally over it
2. Rub the inflated balloon against your hair or jumper and bring it close to the dill

#### Results and Explanation

The dill will follow the balloon as you move it about. Some might even leap up to meet the balloon!

Rubbing the balloon makes it negatively charged and this induces a positive charge in the dill. The attraction between the balloon and dill can be large enough to overcome gravity.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Static UFO

Charge
Electricity and Magnetism

## Static UFO

At home for 5-11 11-14

#### What you need

• Very thin strands of tinsel, about 15cm long
• Balloon

#### Instructions

1. Tie six strands of tinsel together with a knot at each end and cut any loose ends off close to the knots
2. Rub the inflated balloon against your hair or jumper and hold the tinsel above the balloon by one of the knots. Drop the tinsel

#### Results and Explanation

The tinsel will touch the balloon, be repelled and start floating! Use the balloon to direct where it goes. If your UFO won’t fly, try again with thinner tinsel or on a very dry day.
Rubbing the balloon makes it negatively charged and the tinsel is attracted to it. When the tinsel hits the balloon, it picks up some of the negative charge and is repelled away.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Static Spinning Straw

Charge
Electricity and Magnetism

## Static Spinning Straw

At home for 5-11 11-14

#### What you need

• A drinking straw
• Plastic bottle cap
• A jumper

#### Instructions

1. Place the plastic bottle cap on a table.  Rub the straw with a jumper several times in the same direction and then carefully balance the straw on the cap
2. Bring one hand close to the straw, but don’t touch it. The straw will start to spin!
3. Experiment with where to put your hand to get the best response. Does one end of the straw respond better than the other? Does using two hands rather than one make a difference?

#### Results and Explanation

Rubbing the straw makes it negatively charged and this induces a positive charge in your hand. The attraction between the straw and your hand makes the straw follow your hand as you move it.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Eerie Blue Water

The Electromagnetic Spectrum
Light Sound and Waves

## Eerie Blue Water

At home for 5-11 11-14

#### What you need

• Two clear glasses
• Tap water
• Tonic water
• Dark paper

#### Instructions

1. Fill one glass with tap water and the other with tonic water and put them both in direct sunlight
2. Holding the dark paper behind them, but not blocking the light, look across the surfaces of the water

#### Results and Explanation

The tonic water will be giving off an eerie blue glow! Tonic water contains quinine. The quinine absorbs ultraviolet light from the Sun and re-emits it as visible blue light.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Supercool

Phase Change
Properties of Matter

## Supercool

At home for 5-11 11-14

#### What you need

• Bottled or distilled water (not tap water)
• Freezer

#### Instructions

1. Put the bottle of water in to the freezer
2. Leave it alone for two to three hours. You’ll need to experiment with the exact timing as all freezers are different
3. Check regularly that the water is still liquid – but don’t move the bottle! While the water is still liquid, take the bottle out of the freezer carefully, then tap it suddenly on the edge of a table

#### Results and Explanation

The water will freeze! Water can stay liquid for several degrees below 0°C if there are no impurities or disturbances to start ice crystals forming. Tapping the bottle disturbs the ‘supercooled’ water and kicks off freezing.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Psychedelic Milk

Properties of Matter

## Psychedelic Milk

At home for 5-11 11-14

#### What you need

• Shallow bowl
• Milk
• Food colouring
• Washing up liquid

#### Instructions

1. Pour a couple of centimetres of milk in to the bowl
2. Add a couple of drops of food colouring at even spaces around the edge of the bowl
3. Add a drop of washing up liquid to the centre of the bowl

#### Results and Explanation

The colours start to mix and churn! The washing up liquid reduces the surface tension of the milk causing swirls and eddies as the detergent spreads through the liquid.
What happens if you use skimmed or full fat milk? Does warming the milk first make any difference?

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Penny Rocket

Pressure
Properties of Matter

## Penny Rocket

At home for 5-11 11-14

#### What you need

• A penny or other small coin
• Empty bottle with narrow neck
• Some water
• A freezer

#### Instructions

1. Put the clean, empty bottle in the freezer for about an hour, or until it’s really cold
2. Take the bottle out of the freezer.  Wet the mouth of the bottle and quickly put the coin over the mouth, making sure there are no air gaps.  Put the bottle back in the freezer for another hour
3. Take the bottle out of the freezer and, using a cloth, grasp the bottle with both hands
4. Wait
5. Make sure the bottle is pointing away from you and anything breakable!

#### Results and Explanation

Your hands warm the cold air inside the bottle, making it expand and force the coin off the bottle and into the air!

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Mini Magnifier

Refraction
Light Sound and Waves

## Mini Magnifier

At home for 5-11 11-14

#### What you need

• Clear plastic, eg from a pop bottle
• Sticky tape
• Water
• Teaspoon

#### Instructions

1. Cut out a small piece of clear plastic (approx 5 cm by 3 cm) and put sticky tape around the edges if they are sharp
2. Use the teaspoon to put a single small drop of water on to the middle of the plastic
3. Place the plastic carefully over some text and look straight down through the top of the drop

#### Results and Explanation

The text will look bigger! The water drop acts as a magnifying lens. Light from the page travelling through the drop it is bent (refracted) making the text look much bigger.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Marshmallow Shooter

Newtons Second Law
Forces and Motion

## Marshmallow Shooter

At home for 5-11 11-14

#### What you need

• Piece of thin card (A4 size)
• Sticky tape
• Marshmallows

#### Instructions

1. Roll the piece of card lengthways into a tube that is just wide enough to be a snug fit for a marshmallow.  Put tape along the whole length of the tube to hold it together and seal the join
2. Put a marshmallow in one end of the tube, hold the tube horizontal, and blow from the opposite end. If the marshmallow doesn’t move, adjust the diameter of the tube. Note how far it flies
3. Try again with a new marshmallow but this time blow from the end with the marshmallow.  Keep blowing until the marshmallow leaves the tube

#### Results and Explanation

By blowing as the marshmallow travels along the whole length of the tube, you’re applying a force for longer. This means the marshmallow accelerates for longer, emerges from the tube at a greater speed and flies further.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Roses are Blue

Properties of Matter

## Roses are Blue

At home for 5-11 11-14

#### What you need

• White carnation or similar
• Vase
• Water
• Food colouring
• Scissors

#### Instructions

1. Pour water into the vase and add a capful or two of food colouring
2. Cut the end of the stem and place the flower in the coloured water
3. Leave over night
4. With another flower, try cutting carefully halfway up the middle of the stem and putting each half in differently coloured water

#### Results and Explanation

Capillary action forces the water up through the stem and into the petals. The food colouring shows the paths the water takes.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Mirror Mirror

Formation of Images
Light Sound and Waves

## Mirror Mirror

At home for 5-11 11-14

#### What you need

• A small mirror
• A blank wall
• A friend

#### Instructions

1. Sit opposite your friend and next to a pale, blank wall. With the wall to your right, hold the mirror in your left hand and put it next to your nose
2. Angle the mirror so that your right eye sees only a reflection of the wall
3. With your left eye looking at your friend, wave your right hand so your right eye can see it reflected in the mirror
4. Watch bits of your friend’s face disappear!
5. Don’t give up if it doesn’t work straight away – try switching eyes, holding your head very still and making sure your friend doesn’t fidget

#### Results and Explanation

Each eye is seeing something very different and as your brain tries to make a sensible single image, it combines bits from both eyes. But your brain is sensitive to movement so it focuses on your moving hand and your friend disappears.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Musical Tea

Sound Wave
Light Sound and Waves

## Musical Tea

At home for 5-11 11-14

#### What you need

• A teacup or mug
• A teaspoon
• Good ears

#### Instructions

1. If you tap the rim of the teacup by the handle, opposite the handle or at the two points half way round the rim, then you hear a low pitched sound
2. But if you tap the rim of the teacup halfway between those points, you hear a sound that is higher in pitch

#### Results and Explanation

Tapping the rim causes vibrations around the cup, but at the handle the movement is always at a minimum.
So tapping at the specific points on the rim sets up vibrations with different wavelengths and you hear notes of different pitches, or frequencies.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Garden Rainbow

Visible Light
Light Sound and Waves

## Garden Rainbow

At home for 5-11 11-14

• A hosepipe
• A garden
• A sunny day

#### Instructions

1. Stand with your back to the Sun and turn on the hosepipe
2. Put your thumb over the end of the hose to get a fine spray of water
3. Look at the spray against a dark background such as a wall, hedge or grass
4. Adjust your position and the fineness of the spray until you see a rainbow!

#### Results and Explanation

White light from the Sun is made up of light of different wavelengths, or colours.
The different wavelengths of light are bent by different amounts as they pass through the water, splitting the white light into all the colours of the rainbow.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Book Launch

Drag
Forces and Motion

## Book Launch

At home for 5-11 11-14

#### What you need

• A copy of Marvin and Milo’s Adventures in Science (available from bookshops and online retailers)
• A piece of paper smaller than the book

#### Instructions

1. Hold the book and the paper horizontally and drop both at the same time. Notice which one hits the ground first.
2. Now put the piece of paper flat against the bottom side of the book and drop them together. What happens?
3. Drop them again, but this time with the paper on top of the book. What happens?

#### Results and Explanation

Air resistance means that when dropped separately, the book and paper hit the ground at different times. But when they are dropped together, the larger book sweeps the air out of the way and the two fall at the same rate.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bottle Orchestra

Sound Wave
Light Sound and Waves

## Bottle Orchestra

At home for 5-11 11-14

#### What you need

• Two glass bottles
• A wooden spoon
• A jug of water
• Good ears

#### Instructions

1. Fill one bottle ¾ full of water and the other ¼ full of water
2. Tap both bottles and listen to the sound they make. Which one is higher pitched?
3. Now blow across the top of each bottle. Which bottle makes the higher pitched sound now?

#### Results and Explanation

The easier it is for the glass to vibrate when you tap it, the higher the frequency. So the bottle with less water in will sound higher pitched.
The less air there is in the bottle when you blow over it, the faster it vibrates. So the bottle with more water in will sound higher pitched.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Waterproof Sieve

Properties of Matter

## Waterproof Sieve

At home for 5-11 11-14

#### What you need

• A glass bottle
• A sieve
• Water

#### Instructions

1. Fill the bottle with water and hold the sieve over the top of it
2. Turn them both upside down, making sure that the top of the bottle is in contact with the sieve at all times. (It’s best to do this over the sink or outside…)

#### Results and Explanation

The water stays in the bottle! The surface tension of the water across the fine mesh of the sieve stops the water flowing through the holes.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Sound of Gas

Wave Speed
Light Sound and Waves

## Sound of Gas

At home for 5-11 11-14

#### What you need

• A small glass bottle
• Water
• An effervescent indigestion tablet

#### Instructions

1. Pour about 2cm of water into the bottle. Blow across the top of the bottle and listen carefully to the sound it makes
2. Break the tablet in two, and put both halves into the bottle.  Wash your hands while you wait for it to stop fizzing
3. Blow across the top of the bottle again and listen to the sound it makes now

#### Results and Explanation

Sound travels more slowly through carbon dioxide (the gas given off by the fizzing tablet) than through air, so when you blow across the bottle you hear a lower pitched note.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Pouring Light

Total Internal Reflection
Light Sound and Waves

## Pouring Light

At home for 5-11 11-14

#### What you need

• A clear plastic bottle
• A torch
• Kitchen foil
• Sticky tape
• A dark room with a sink

#### Instructions

1. Wrap the bottle in kitchen foil, leaving the bottom bare
2. Fill the bottle with water, switch on your torch and turn off the lights
3. Shine the torch through the bottom of the bottle and start pouring the water into the sink. Keep the torch close to the bottle at all times

#### Results and Explanation

Almost all the light from the torch is reflected every time it hits the edge of the stream of water, so the light follows the path of the water and you see a spot of light where the water hits the sink.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Moody Magnets

Magnet
Electricity and Magnetism

## Moody magnets

At home for 5-11 11-14

#### What you need

• Two flat, rectangular fridge magnets (if you only have circular magnets, you’ll need to do some experimenting to feel this effect!)

#### Instructions

1. Place the magnets side by side on a table: one face up and one face down
2. Put one magnet on top of the other so that the two magnetic sides are touching. Try to slide them apart along the longest side. How easily do they slide?
3. Try sliding them apart again, but this time along the shortest side. How well do the magnets slide now?

#### Results and Explanation

Fridge magnets are made from thin strips of magnets with alternating north and south poles. As you try to slide the magnets across each other, the thin strips are being continually attracted and then repelled making the magnets judder.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Flame Balloons

Specific Heat Capacity
Properties of Matter

## Flame Balloons

At home for 5-11 11-14

#### What you need

• An adult (only do this experiment with a responsible adult and only hold the balloon over the flame for a short time*)
• Two balloons
• Some water
• A tea light
• Matches

#### Instructions

1. Place the tea light on a flat surface and light it. Make sure it is away from anything flammable or electrical.
2. Blow up one of the balloons and hold it over the flame. The balloon will pop!
3. Add some water to the second balloon and then blow it up. What happens when you hold this balloon over the flame?

#### Results and Explanation

It doesn’t pop as the heat from the candle is transferred to the water. Water takes a long time to heat up, so it stays relatively cool and stops the rubber from getting so hot it bursts.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Swinging Coat Hanger

Centripetal Force
Forces and Motion

## Swinging Coat Hanger

At home for 5-11 11-14

#### What you need

• A metal coat hanger
• A pound coin
• A file

#### Instructions

1. Carefully pull the coat hanger out of shape until it forms a square. Bend the hook so that it points towards the newly-formed corner and file the end flat
2. With the coat hanger on one finger, balance the coin on the hook. This might take some patience!
3. Once the coin is in place, start swinging the hanger back and forth. Can you get the hanger to swing in a complete circle without the coin falling off?

#### Results and Explanation

The circular motion of the hanger means that a centripetal force acts to keep the coin firmly in place while you’re swinging.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Falling Bubbles

Properties of Matter

## Falling Bubbles

At home for 5-11 11-14

#### What you need

• A plastic drinks bottle
• Water

#### Instructions

1. Fill the bottle with water so it is very nearly full
2. Put the lid on tightly and throw the bottle in the air. Watch it carefully on the way up and down
3. The air inside the bottle will form a spherical bubble as it’s falling!

#### Results and Explanation

When the bottle is in free-fall, surface tension forces the air into a bubble with the least possible surface area – a sphere. In space, the same effect can be seen with liquid drops in air.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Skewered

Inertia
Forces and Motion

## Skewered

At home for 5-11 11-14

#### What you need

• A metal skewer (or knitting needle)
• An apple
• A hammer

#### Instructions

1. Push the skewer through the centre of the apple until it is sticking out by about 5cm
3. Holding the skewer horizontal, hit the blunt end with the hammer. What happens?
4. Holding the skewer vertically, what happens this time when you hit the skewer?

#### Results and Explanation

In both cases, the skewer moves further through the apple each time you hit it because of the apple’s inertia.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Heat's Rising

Convective Heating
Energy and Thermal Physics

## Hot Water Rising

At home for 5-11 11-14

#### What you need

• Two plastic drinks bottles
• Cold water
• Hot water
• Sink
• Piece of card
• Red food colouring

#### Instructions

1. Fill one bottle with cold water and the other with hot water from the tap. Add some red food colouring to the hot water
2. Hold the card firmly over the top of the cold water bottle, turn it upside down and balance it on top of the hot water bottle
3. Align the bottles and carefully remove the card. Do this in the sink just in case!

#### Results and Explanation

Hot water is less dense than cold water so it rises into the top bottle while the cold water sinks into the bottom bottle. This convection continues until the water is the same temperature throughout both bottles.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Reappearing Coin

Refraction
Light Sound and Waves

## Reappearing Coin

At home for 5-11 11-14

• Coin
• Mug
• Jug of water
• Blu Tack
• A friend

#### Instructions

1. Stick the coin to the bottom of the empty mug
2. Step back, or move your head, until you can no longer see the coin in the mug
3. While you stay in position, get your friend to slowly pour water into the mug

#### Results and Explanation

The coin reappears because the water bends, or refracts, the light travelling from the coin so that it can now reach your eye.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Electric Seasoning

Charge
Electricity and Magnetism

## Electric Seasoning

At home for 5-11 11-14

#### What you need

• Ground pepper
• Ground salt
• Balloon

#### Instructions

1. Rub the balloon on your hair or a jumper and then hold it about 2cm above the pile of salt and pepper.

#### Results and Explanation

Rubbing the balloon makes it negatively charged and both the salt and pepper are attracted to it. However, the pepper grains are lighter than the salt, so it is the pepper that leaps towards the balloon.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Up next

Equilibrium
Forces and Motion

At home for 5-11 11-14

• A friend

#### Instructions

1. Hold the slinky up at arm’s length by its top coils
2. With your friend keeping a close eye on the bottom of the slinky, let go of the top (you may need to do this several times to see what’s happening)

#### Results and Explanation

The bottom coil of the slinky remains stationary until the top coils reach it and then the whole slinky drops to the floor together!
When the top coils are released, the forces on the bottom coil (the tension in the spring and gravity) are still balanced. It is not until the slinky has contracted that gravity exceeds tension in the bottom coil and it starts to fall.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Invisible Bowl

Refractive Index
Light Sound and Waves

## Invisible Bowl

At home for 5-11 11-14

#### What you need

• A large Pyrex® bowl
• A small Pyrex® bowl
• Vegetable oil

#### Instructions

1. Pour enough vegetable oil into the large Pyrex® bowl so you’ll be able to completely submerge the small bowl in it
2. Carefully lower the small bowl into the vegetable oil
3. The small bowl disappears as it gets covered in oil!

#### Results and Explanation

The refractive index of Pyrex® glass is the same as that for vegetable oil so as light passes through the glass of both bowls and the oil it doesn’t bend – refract – at all and you can’t see the small bowl.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### All Change

Density
Properties of Matter

## All Change

At home for 5-11 11-14

#### What you need

• Two small shot glasses
• Apple juice
• Water
• A small piece of card

#### Instructions

• Fill one glass to the brim with water
• Fill the second glass to the brim with apple juice and place the card over the top of it
• Holding the card in place, carefully turn the juice glass upside down and put it on top of the water glass so that the card is sandwiched between them both
• Making sure that the glasses are aligned, slowly slide the card to one side to make a tiny gap (~1mm) between the glasses. Watch and wait

#### Results and Explanation

After about 20 mins the juice and the water will have swapped places because water is less dense than sugary fruit juice.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Cloud in a Glass

Phase Change
Properties of Matter

## Cloud in a Glass

At home for 5-11 11-14

#### What you need

• Pint glass
• Small bowl
• Hot water
• Ice
• Aerosol spray (e.g. deodorant)

#### Instructions

1. Pour about 3cm of hot water into the glass and carefully swirl it about to warm the glass
2. Put the ice in the small bowl and balance the bowl on top of the glass
3. Lift the bowl and spray some deodorant into the glass, replacing the bowl quickly afterwards
4. Wisps of cloud form in the glass!

#### Results and Explanation

Clouds form when warm, moist air cools and the water condenses into droplets. But droplets need a surface on which to form. In the atmosphere this is dust particles and in this experiment it is the aerosol particles.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Drinks Cooler

Phase Change
Properties of Matter

## Drinks Cooler

At home for 5-11 11-14

#### What you need

• Two small plastic bottles
• Kitchen paper
• Sticky tape
• Drinking water at room temperature
• A breezy day (on a still day, you’ll just have to wait a bit longer)

#### Instructions

1. Fill both bottles with room-temperature drinking water
2. Wrap one of the bottles in two layers of kitchen paper, holding it in place with sticky tape. Wet the paper with water
3. Put both bottles outside in a breezy spot and leave them for 25 minutes before drinking

#### Results and Explanation

Water in the kitchen paper evaporates, taking heat from the water in the bottle and cooling it. Any breeze speeds up the evaporation and hence the cooling.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Overflowing Coins

Properties of Matter

## Overflowing Coins

At home for 5-11 11-14

#### What you need

• A glass of water
• A pile of coins
• A saucer
• Some washing up liquid

#### Instructions

1. Fill the glass to the very brim with water and place on top of the saucer
2. Carefully drop a coin in to the water, edge first
3. Slowly and carefully drop more coins in to the water – how many can you add before the glass overflows?
4. Try again, but this time add a few drops of washing up liquid to the water before you start adding the coins

#### Results and Explanation

Water molecules are strongly attracted to each other, creating a surface tension that allows the water to bulge over the top of the glass as you add the coins. But washing up liquid reduces the surface tension so the glass overflows sooner.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Power of Words

Atmospheric Pressure
Properties of Matter

## Power of Words

At home for 5-11 11-14

• A table
• A ruler
• A newspaper

#### Instructions

1. Lay the ruler on the table so about a third of it hangs over the edge
2. Carefully lay a single sheet of newspaper flat on the table and over ruler
3. Hit the end of the ruler with your hand – the ruler stays where it is!
4. What happens if you try again, but this time with the sheet of newspaper folded up?

#### Results and Explanation

The flat sheet of newspaper has a large enough area so that the downward force of the atmosphere counters the upward force from the ruler. But the folded-up newspaper has a much smaller surface area, so doesn’t stop the ruler from going flying when it’s hit.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bee Swinger

Sound Wave
Light Sound and Waves

## Bee Swinger

At home for 5-11 11-14

#### What you need

• An ice lolly stick
• Blu Tack
• String
• A thick rubber band
• Sticky tape
• Thin card
• Scissors

#### Instructions

1. Put a blob of Blu Tack at both ends of the lolly stick
2. Cut a piece of thin card so it fits between the blobs, then tape it to the stick
3. Tie a piece of string securely next to one of the blobs of Blu Tack
4. Then stretch the rubber band around the lollystick
6. Try cutting the card into difference shapes - can you hear a difference?

#### Results and Explanation

As the been swinger moves through the air, the rubber band starts to vibrate. The card amplifies the sound so that you can hear it.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bottle Blowing

Frequency
Light Sound and Waves

## Bottle Blowing

At home for 5-11 11-14

#### What you need

• Two identical glass bottles
• A friend

#### Instructions

1. Ask your friend to hold one bottle up to their ear
2. Standing quite close to your friend, blow across the mouth of your bottle and in the direction of your friend, so that you make a clear note
3. Your friend will hear a similar note in their bottle!

#### Results and Explanation

The two identical bottles vibrate at the same natural frequency. So when one vibrates and produces a note, this makes the other vibrate and produce a similar note.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Silent Bell

Sound Wave
Light Sound and Waves

## Silent Bell

At home for 5-11 11-14

#### What you need

• Glass bottle
• Pipe cleaner
• Small bell
• Wine saver pump and stopper

#### Instructions

1. Attach one end of the pipe cleaner to the bell. Attach the other end to the stopper so that it can still form a good seal with the bottle
2. Put the stopper in the bottle, making sure that the bell doesn’t hit the side of the bottle when you shake it. You should be able to hear the bell
3. Use the wine saver pump to take as much air out of the bottle as you can. Then shake the bottle again

#### Results and Explanation

You can’t hear the bell as you have created a partial vacuum inside the bottle. Without the air in the bottle, the sound is unable to travel from the bell to your ear.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Psychic Paper

Convective Heating
Energy and Thermal Physics

## Psychic Paper

At home for 5-11 11-14

#### What you need

• A small, rectangular piece of thin paper
• A sharp pencil

#### Instructions

1. Fold the paper in half along the long side and then fold it in half along the short side so that you can find the middle
2. Carefully balance the paper on the point of the pencil
3. Bring one hand close to the paper and command the paper to move!

#### Results and Explanation

The paper starts to spin because the heat of your hand heats up the air. This sets up a convection current in the air which moves the paper.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Salty Straws

Density
Properties of Matter

## Salty Straws

At home for 5-11 11-14

#### What you need

• Two small cups tea or coffee
• Two straws
• Salt
• A friend

#### Instructions

1. Pour equal amounts  tea or coffee into two small cups, with the help of a friend if you need it
2. Add enough salt to one cup so that no more salt can dissolve
3. Place a straw into each cup, put a finger over the end of each straw and lift the straws out
4. The liquid should be lower in the straw from the salty tea or coffee

#### Results and Explanation

The salt increases the density of the liquid, which means less of it is picked up when the straws are lifted.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Floating Egg

Upthrust
Properties of Matter

## Floating Egg

At home for 5-11 11-14

#### What you need

• A raw egg
• Glass of water
• Salt
• Fresh water

#### Instructions

1. Fill up a glass with water until it's about half full. Then add four tablespoons of salt and stir until dissolved
2. Put the egg in the glass. The egg should float
3. Gently pour fresh water into the glass. The egg should start to sink
4. Add just enough water so the egg is floating in the middle of the glass

#### Results and Explanation

Adding fresh water dilutes the salt water and reduces the amount the water lifts the egg.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Coloured Rain

Density
Properties of Matter

## Coloured Rain

At home for 5-11 11-14

#### What you need

• Empty glass jar
• Oil
• Food colourings in different colours
• Water

#### Instructions

1. Fill up a jar with warm water
2. In the lid, mix a few tablespoons of oil with a few drops of food colouring
3. Pour this mixture into the water
4. A stream of colour will now start falling down

#### Results and Explanation

Food colouring and oil don't mix, and as the two separate the food colouring sinks into the water, leaving trails of colours.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Leaning Tower

Phase Change
Properties of Matter

## Leaning Tower

At home for 5-11 11-14

#### What you need

• Plastic box
• Sand
• Water
• Smooth brick or other heavy object
• Rubber mallet

#### Instructions

1. Fill half a plastic box with sand
2. Add water until it fills up to just below the level of the sand
3. Place a heavy object upright in the sand
4. Tap the side of the box with the mallet and you'll notice the object will begin to fall over

#### Results and Explanation

Tapping the side of the box makes the sand particles move over each other, making the heavy object fall over.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Gloveaphone

Standing Wave
Light Sound and Waves

## Gloveaphone

At home for 5-11 11-14

#### What you need

• A thin latex glove
• A straw
• A cardboard tube with open ends
• Tape

#### Instructions

1. Cut a small hole in one of the fingers of the glove
2. Feed the straw a small way through the hole into the glove. Seal off with tape
3. Put the end of the glove over the cardboard tube and tape down the glove to the tube, making sure there are no gaps
4. Pull the rest of the fingers of the glove down against the side of the tube so a tight skin is made at the end of the tube
5. Blow into the straw until a sound is made. The glove should inflate

#### Results and Explanation

The latex glove vibrates as air flows down the tube. This creates a standing wave in the air along the length of the tube which we hear as sound.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Paper Popper

Pressure
Properties of Matter

## Paper Popper

At home for 5-11 11-14

#### What you need

• An empty wine bottle
• Piece of paper

#### Instructions

1. Scrunch up a piece of paper small enough to fit into the neck of the bottle
2. Hold the bottle horizontally and place the piece of paper just inside the neck of the bottle
3. Try to blow the piece of paper into the bottle. The paper will fly out instead

#### Results and Explanation

The bottle is already full of air, so it's very hard to blow more air into it. When you do blow into the bottle the air comes back out, pushing the piece of paper out.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Big Bubble Maker

Properties of Matter

## Big Bubble Maker

At home for 5-11 11-14

• A straw
• Soap
• Scissors
• Water

#### Instructions

1. Get a straw and carefully cut the end into four
2. Push the ends out so they look like a flower with four petals
3. Dip the flower in soapy water and gently blow through the straw

#### Results and Explanation

The petals help the bubble to become big by holding the soapy water in the petals so the bubble doesn't stretch too thin and burst.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Magic Fountain

Atmospheric Pressure
Properties of Matter

## Magic Fountain

At home for 5-11 11-14

#### What you need

• Plastic cup
• Bendy straw
• Scissors
• Glue or Blu-Tack

#### Instructions

1. With the scissors make a small hole in the bottom of the cup (you might need a friend to help).
2. Push the straw through the hole so the bendy bit is inside the cup
3. Glue or use some Blu-Tack to seal the hole and hold the straw in place.
4. Slowly fill the cup with water. Once the water is past the top of the bend, water will start to flow through the straw.

#### Results and Explanation

Once the water begins to flow through the straw, the rest of the water follows as it's pulled through.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Growler

Sound Wave
Light Sound and Waves

## Growler

At home for 5-11 11-14

#### What you need

• Cardboard box
• Pencil
• String
• Wet cloth

#### Instructions

1. Make a hole in a cardboard box.
2. Tie some string round a pencil, and feed the string through the hole so the pencil is inside the box.
3. Use a wet cloth to pull on the string.

#### Results and Explanation

The box amplifies the vibrations from the string as the cloth is pulled along it, making a sound that our ears can hear.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Screech

Sound Wave
Light Sound and Waves

## Screech

At home for 5-11 11-14

• Paper
• Scissors

#### Instructions

1. Fold a small piece of paper three times so you have a concertina
2. Cut two slits into the middle ridge
3. Hold the paper up to your mouth and blow

#### Results and Explanation

The high-pitched sound you hear is created by the paper vibrating.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Thirsty Bottle

Energy Transferred by Heating
Energy and Thermal Physics

## Thirsty Bottle

At home for 5-11 11-14

#### What you need

• Glass bottle
• Plate
• Hot water
• Room temperature water

#### Instructions

1. Pour some water onto a plate
2. Fill the bottle with hot water. The water and the bottle will be hot so you might need to ask a friend to help.
3. Carefully pour the water away and quickly place the bottle upside down on the plate of water. The water will rise up the bottle.

#### Results and Explanation

The hot bottle heats the air inside it. Once the air cools it takes up less space. The air pressure inside the bottle becomes less than the air pressure outside. This forces the water up the bottle.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Water Scales

Upthrust
Properties of Matter

## Water Scales

At home for 5-11 11-14

• Ruler
• Pencil
• Two cups
• Water

#### Instructions

1. Place the middle of a ruler over a pencil.
2. Put two cups with the same amount of water on either end of the ruler.
3. Put your finger in the cup that is lifted.

#### Results and Explanation

As you put your finger in the water, the water tries to push up and float your finger. Because of this the finger pushes down on the water at the same time, causing the cup to tip.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Foil Float

Density
Properties of Matter

## Foil Float

At home for 5-11 11-14

• Bucket
• Foil
• Water

#### Instructions

1. Fill up a bucket with water.
2. Scrunch one piece of foil in the air and put it in the bucket.
3. Scrunch the other one underwater.

#### Results and Explanation

One piece of foil will sink and the other will float.

The piece of foil scrunched above water traps some of the air, which helps it to float.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Fork Balancer

Equilibrium
Forces and Motion

## Fork Balancer

At home for 5-11 11-14

#### What you need

• Tall glass
• Two identical forks
• Toothpick

#### Instructions

1. Push the prongs of the two forks together
2. Push the toothpick between the prongs to hold the forks together
3. Balance the end of the toothpick on the side of the glass

#### Results and Explanation

The forks can hang off the side because all the forces are balanced.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Up next

Constructive Interference
Light Sound and Waves

At home for 5-11 11-14

#### What you need

• Disposable cup
• Sticky tape
• Scissors

#### Instructions

1. Turn the cup upside down so that the base is facing you.
2. Carefully use scissors to make a small hole. Ask friend to help.
3. Insert about 3 cm of the slinky through the hole in the cup, stick it in place using sticky tape.
4. Hold the cup and let the slinky drop. Tap the bottom of the slinky and it’ll make laser noises!

#### Results and Explanation

Slinkies make sound because they vibrate when they stretch out. When they vibrate, they make the air around them vibrate. Both the cup and the air inside it vibrate with the vibrations of the slinky. These build up, and the sound gets louder. This is called amplification.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Blowing Bags

Atmospheric Pressure
Properties of Matter

## Blowing Bags

At home for 5-11 11-14

#### What you need

• Plastic bin bag

#### Instructions

1. Hold the bin bag about 5 cm away from your mouth. Make sure it's not any closer!
2. With your thumb and forefinger create a circle to place the entrance to the bag on.
3. Gently blow into the bag. The bag will inflate quickly!

#### Results and Explanation

When you blow directly into the bag, the only air flowing into the bag is from your lungs. When you blow from a short distance away you create an air flow that also takes in the surrounding air, which is used to inflate the bag.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Resting Egg

Conservation of Momentum
Forces and Motion

## Resting Egg

At home for 5-11 11-14

#### What you need

• A broom
• A glass
• An egg
• A paper plate
• An empty toilet paper roll

#### Instructions

1. Fill the glass half-way with water and set it near the edge of a counter or table.
2. Place the paper plate on top of the glass, with the edge of the plate slightly over the table edge. Stand the toilet paper roll in the middle of the plate, making sure that it's over the centre of the glass. Place the egg on the toilet roll.
3. Stand with the broom next to the table edge, with the handle in front of the plate. Place one foot on the bristles, bend back slightly, then let go!

#### Results and Explanation

When the broom hits the plate, the plate and toilet roll are knocked away and the egg falls into the glass, because it is not moving sideways as the plate and toilet roll move away. Objects do not start to move in a given direction unless acted on by an external force in that direction.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Paperclip Afloat

Properties of Matter

## Paperclip Afloat

At home for 5-11 11-14

#### What you need

• A paperclip
• A cereal bowl
• Water
• Washing-up liquid
• A tissue

#### Instructions

1. Put the paperclip on a flat piece of tissue in the empty bowl.
2. Fill the bowl with water, being careful not to pour water directly on top of the paperclip and tissue.
3. The tissue will sink as it absorbs water, but the paperclip will float! Now put a drop of washing-up liquid in the bowl. The paperclip will sink!

#### Results and Explanation

Though the paperclip should be heavy enough to sink, the surface tension of the water holds it up. When the washing-up liquid dissolves in the water it lowers the overall surface tension, so the paperclip sinks.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Spinning Seat

Conservation of Angular Momentum
Forces and Motion

## Spinning Seat

At home for 5-11 11-14

#### What you need

• A swivel chair
• Two heavy food cans
• Cushions

#### Instructions

1. Sit an adult in the chair and ask them to hold a can in each hand with their arms stretched out at right angles. Put some cushions on the floor round them, for safety.
2. Set the chair spinning. When it has reached a steady speed, ask them to quickly pull in their arms tight to their body, still holding the cans.
3. The chair will spin much faster!

#### Results and Explanation

The chair, person and cans together have something called angular momentum, which depends on how fast they're spinning and how far out the cans are held.
As the angular momentum has to stay the same, tucking in your arms means the speed has to go up to compensate - so the chair spins faster.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Walking Water

Properties of Matter

## Walking Water

At home for 5-11 11-14

#### What you need

• Seven clear plastic cups
• Food colouring
• Water
• Paper towels
• Scissors

#### Instructions

1. Line up the cups and fill every odd one with water. Stir various food colourings into the water-filled cups – e.g. red in the 1st and 7th, yellow in the 3rd, blue in the 5th.
2. Fold some paper towels to make upside-down V-shaped arches. Trim them so that they can link every cup with its neighbour, with the ends touching the bottom of the cups.
3. Wait for several hours. Water will end up in all of the cups and the colours will be mixed!

#### Results and Explanation

Water overcomes gravity and rises up the arches as it is attracted to the cellulose in them and to the water already absorbed. Once the arches are saturated, the water seeps out again and mixes with coloured water from the next arch to make new colours.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Magnetic Cereal

Magnetic Force
Forces and Motion

## Magnetic Cereal

At home for 5-11 11-14

#### What you need

• Cereal fortified with iron
• Magnets
• A bowl
• A pestle or spoon

#### Instructions

1. Put some of the dry cereal in the bowl and crush it as small as possible with the pestle or spoon.
2. Put a magnet into the cereal and shake the bowl a little.
3. Lift the magnet out – some cereal should stick to it. If not, try stronger magnets or other cereal brands. It should work with brands where the iron is present as fine metal particles or ferric oxide, as these are magnetic.

#### Results and Explanation

The attraction isn’t strong enough to lift large flakes, as each contains only a few magnetic particles. In crushed cereal the magnet just picks up pieces containing magnetic particles – in these each particle has less cereal to lift.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Deceptive CD

Visible Light
Light Sound and Waves

## Deceptive CD

At home for 5-11 11-14

#### What you need

• Paper
• Scissors
• Strong glue
• Coloured pens
• An old CD
• A marble

#### Instructions

1. Make a circular shape from the paper using the CD to draw round. Colour it in with the rainbow colours in equal segments.
2. Make a hole at the centre of the shape, glue it to the CD and stick the marble to the CD through the hole. (Get an adult to help if you use very strong glue.)
3. Spin the whole thing fast – the colours should turn to white!

#### Results and Explanation

Light of certain wavelengths excites different types of cell in your eyes so you see these inputs as colours. As the CD spins, light reflected from different parts hits your eyes too fast for your brain to tell these apart so you see white light.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Microwave marathon

Phase Change
Properties of Matter

## Microwave marathon

At home for 5-11 11-14

#### What you need

• Ice cubes
• Tap water
• Scales
• A microwave oven
• Identical microwave-safe cups

#### Instructions

1. Put a few ice cubes into a dry cup and weigh it.
2. Pour water into another cup until it weighs the same as the first one. (It is dangerous to heat distilled water in a microwave, so use tap water.)
3. Stand the cups on opposite sides of the oven’s turntable and microwave them. The water should boil before the ice melts.

#### Results and Explanation

Inside the microwave there's a quickly-changing electric field. Water molecules are slightly charged at both ends, and want to align themselves with this electric field. Because the field keeps changing, the molecules in liquid water are spun back and forth, raising the temperature of liquid quickly. The water molecules in ice are fixed in a crystal structure, and so cant rotate and so the temperature doesn't increase as much.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Pressure Fountain

Pressure
Properties of Matter

## Pressure Fountain

At home for 5-11 11-14

#### What you need

• A plastic bottle
• Scissors
• A straw
• Putty
• Food colouring
• A balloon

#### Instructions

1. Make a small hole about 10 cm from the bottom of the bottle, stick the straw through it till half remains outside, pointing upwards Seal the hole with putty
2. Fill the bottle halfway with water dyed with the food colouring. No water will come out of the straw
3. Blow up the balloon, keeping the air inside as you stretch the neck over the top of the bottle, then release. Water spurts from the straw as the balloon deflates!

#### Results and Explanation

Air presses down equally on the water in the bottle and in the straw at first, but attaching the inflated balloon increases the air pressure in the bottle. As it deflates, the air presses down on the water, pushing it through the straw.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Electric Slime

Charge
Electricity and Magnetism

## Electric Slime

At home for 5-11 11-14

#### What you need

• Cornflour
• A tablespoon
• A cup
• Putty
• Vegetable oil
• Polystyrene or a balloon

#### Instructions

1. Mix two to three tablespoons of cornflour with vegetable oil in the cup to make a gloopy, slime-like thick cream
2. Rub the polystyrene or balloon on your hair
3. Make a stream with the slime by pouring it from the tablespoon back into the cup. Wave the polystyrene object or balloon near the slime stream. The slime should move towards the balloon and become much thicker

#### Results and Explanation

The slime is made of tiny particles of starch surrounded by oil. Rubbing the object makes it negatively charged and it attracts the positive ends of the starch particles so that these line up and clump together.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Free Fall Ride

Drag
Forces and Motion

## Free Fall Ride

At home for 5-11 11-14

#### What you need

• A coin, preferably a £2 piece
• Paper
• Scissors

#### Instructions

1. Cut out a paper disc a bit smaller than the coin. Hold the coin horizontally in one hand and the paper disc in the other, then let them fall
2. The coin falls much faster than the paper, as you would expect
3. Now place the paper disc on top of the coin, and let them fall together. The paper falls almost as fast as the coin

#### Results and Explanation

It is air resistance that makes the paper fall slowly, and the coin pushes the air out of the way for both itself and the paper when you drop them together. In a vacuum, all objects fall at the same speed, as astronaut David Scott once showed on the Moon.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Remote Detector

The Electromagnetic Spectrum
Light Sound and Waves

## Remote Detector

At home for 5-11 11-14

#### What you need

• A remote control
• A digital or phone camera, with a screen

#### Instructions

1. Look at the end of the remote while pressing its buttons – you shouldn’t see anything happening
2. Now switch on the camera, point the remote at the camera screen and press the buttons
3. The screen should show a flashing blue or purple light at the end of the remote. (If not, try a friend’s camera or remote)

#### Results and Explanation

Your remote sends signals using waves of infrared light. The light’s invisible to you, but not to your camera, which picks it up and converts it to a colour that you can see.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Dogged Drifter

Properties of Matter

## Dogged Drifter

At home for 5-11 11-14

#### What you need

• A ping-pong ball
• A plastic cup
• Water

#### Instructions

1. Fill the cup almost full and float the ping-pong ball on it – it should be impossible to stop it drifting to the rim
2. Add more water until the cup almost overflows and the surface is raised. Now you should be able to keep the ball in the centre, though it looks unstable

#### Results and Explanation

The water’s surface tension pulls down on the ball but water is also attracted to it and climbs up its sides. Overall the pull is diagonally down.
Near the rim, the water between ball and rim flattens, so the overall pull is towards the rim. But in a bulging cup, the water’s surface is almost vertical at the rim, so the overall force pulls the ball to the centre.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Heavy Atmosphere

Atmospheric Pressure
Properties of Matter

## Heavy Atmosphere

At home for 5-11 11-14

#### What you need

• A vacuum cleaner
• A large, strong, clear plastic bag
• Bathroom scales
• A board about the scales’ size
• Sticky tape

#### Instructions

1. Place the board under the scales, put them together into the bag and wrap the plastic round them, fastening with sticky tape
2. Stand the bag flat on the floor, put the vacuum pipe into the bag and hold the plastic tight round it. Switch the machine on
3. Once the air has been sucked from the bag, the scales should read about 150kg or more; with a perfect set-up they’d record about a tonne! (You may need to try different scales or reset them for this to work)

#### Results and Explanation

Normally, the air above and below empty scales pushes equally in all directions, so the forces cancel out and they read zero. With a nearly airless bag, the weight of the atmosphere pushes down on the scales but little force pushes up.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Free Fluid

Terminal Velocity
Forces and Motion

## Free Fluid

At home for 5-11 11-14

#### What you need

• A large plastic bottle
• Scissors
• Some water
• An outdoor space

#### Instructions

1. Cut a hole about 1cm across in the side of the bottle and stand it on the ground
2. Keep your finger over the hole and fill the bottle with water
3. Take your finger away – water should spurt from the hole
4. Repeat what you did, but drop the bottle from above shoulder height as you remove your finger. This time, no water pours from the bottle while it falls

#### Results and Explanation

In the standing bottle, gravity pulls on the water so it presses on the bottom and sides and escapes through the hole. When you drop the bottle, both it and the water fall at the same rate so the water doesn’t press on anything – it’s as if it was floating inside the bottle.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Unsliced ice

Phase Change
Properties of Matter

## Unsliced ice

At home for 5-11 11-14

#### What you need

• An ice cube
• Polystyrene
• About 20cm of thin wire
• Two equal weights e.g. full drinks bottles
• A sturdy piece of wood and a brick

#### Instructions

1. In a cold room, weight the wood down on a table with the brick. Let the end jut over the edge and put a slab of polystyrene on it
2. Fix the weights to each end of the wire – use strong tape if necessary
3. Hang the wire over the middle of the ice cube. Wait for some time. The wire should cut its way through the ice but leave the ice cube in one piece

#### Results and Explanation

Because ice is less dense than water, pressure from the wire squeezes and helps to melt it. (Scientists are still trying to understand all the reasons why it melts!) As the wire moves down, the water refreezes above it.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Unbalanced balloons

Pressure
Properties of Matter

## Unbalanced balloons

At home for 5-11 11-14

#### What you need

• Two similar balloons
• Two sports drinks bottles
• Tape
• Something to cut the ends off the bottles

#### Instructions

1. Cut the lock and screw ends off both bottles, keep the ends unlocked and stretch a balloon over each one
2. Blow up one balloon a little and lock the cap. Blow up the other a lot more and lock
3. Tape the caps together and unlock – air flows from the small balloon to the larger one and inflates it even more!

#### Results and Explanation

The small balloon’s surface is very curved, so most of the tension in the rubber squeezes down on the air, increasing its pressure. The big balloon has a flatter surface, so the tension in the rubber mostly pulls on other rubber.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Polar Opposites

Polarisation
Light Sound and Waves

## Polar Opposites

At home for 5-11 11-14

#### What you need

• Transparent sticky tape
• Piece of clear plastic
• Two “polarisers” – pieces of polarising plastic (or two old sunglass lenses)
• A bright lamp

#### Instructions

1. View the lamp through two polarisers at once. Rotate one of them until you can block the light
2. Now stick strips of tape on the clear plastic, criss-crossing them. Sandwich the plastic between the two polarisers
3. Look at the lamp through the “sandwich”. Rotate the polariser closest to you – you should see a kaleidoscope of coloured patterns

#### Results and Explanation

Light travels in one direction but vibrates at right-angles to this – sideways and up and down. Polarisers let only the horizontal or vertical part through, so you can combine them to block light.

In the “sandwich” the stretched tape slows down and rotates the polarised light, shifting the different wavelengths (ie colours) of light by different angles. As these hit the second polariser, different wavelengths get through as you rotate it, making coloured patterns.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Mirror Magic

Reflection
Light Sound and Waves

## Mirror Magic

At home for 5-11 11-14

#### What you need

• A large framed mirror
• Two firm supports to hold it up
• A person to watch you

#### Instructions

1. Stand the mirror upright so that it just reaches the top of your legs. Hold it in place firmly with two supports - make sure it can't fall over
2. Point your finger at the mirror - what do you see? How far behind the mirror does your finger appear to be?
3. Straddle the mirror with one leg behind the mirror and one in front. Keep the leg behind the mirror on the ground and lift the one in front

#### Results and Explanation

To an onlooker it will seem as if you're floating or flying!
A mirror reverses the direction in which an image points in and out of it. People see the outside of your real leg lifted up and an image of the inside of it, so to them it looks like two legs lifted up.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Liquid Strength

Phase Change
Properties of Matter

## Liquid Strength

At home for 5-11 11-14

#### What you need

• About 5 kg of cornflour
• Water
• A large bowl

#### Instructions

1. Find a place where it’s OK to get messy. Mix some of the cornflour and water together into a thick paste. Keep mixing until it’s ankle-deep
2. Jump very suddenly onto the mixture. Try jumping on and off, or standing still

#### Results and Explanation

You shouldn't sink if you jump suddenly, but if you stand on it, you'll gradually sink.
The mixture is a special type of liquid that gets less runny when you stir it and turns solid if you hit it hard. The force of the impact makes the starch in the cornflour clump together so it supports your weight at first.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Freezing Time

Energy Transferred by Heating
Energy and Thermal Physics

## Freezing Time

At home for 5-11 11-14

#### What you need

• A cheap battery-driven clock
• A freezer
• A small plastic box
• Tissue paper or cotton wool

#### Instructions

1. Take the clock and put it in the box. Pack it in with tissue paper or cotton wool to keep it dry. Don't use your best clock, just in case it gets damaged!
2. Put the box in the freezer and leave it for about an hour
3. Take the clock out - is it still working?

#### Results and Explanation

Put it in your living room and wait a day or two – it should start working again eventually.

Batteries use chemical reactions to make a current flow. It flows with much more difficulty inside a battery at freezing temperatures, so that the battery doesn’t work, but it usually returns to normal when it’s warmed up.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Sinking Sugar

Density
Properties of Matter

## Sinking Sugar

At home for 5-11 11-14

#### What you need

• A large sink, bucket or tank
• Water
• 330ml cans of various drinks
• Kitchen scales

#### Instructions

1. Fill the large container with water. Lower the cans into it one by one. Make sure you use a variety of diet, sugary or other drinks
2. Which ones float? Which ones sink?

#### Results and Explanation

You should find that the diet or unsweetened drinks float and the sugary ones sink. Now weigh each can.
Whether something sinks or floats depends on its density. Each can has the same volume but the sugary ones weigh more than the others and so are denser. Sweeteners weigh much less than sugar and some popular fizzy drinks contain about seven teaspoons of sugar or more.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Impossible Tower

Mass
Forces and Motion

## Impossible Tower

At home for 5-11 11-14

#### What you need

• About 15 identical flat blocks or books
• A flat surface

#### Instructions

1. Stack the blocks to make a tall column with each placed exactly over the one beneath. Move the top block to the right as far as it will go without falling
2. Move the top two blocks together so that they overhang the third block as far as possible without falling. Keep going in the same way down the column

#### Results and Explanation

Your stack seems to defy gravity! You have to shift the blocks by tiny amounts towards the end, so it’s extremely difficult to build from the bottom up.

When you balance the first block, its centre of mass is at the edge of the block below. Each time you balance a new block plus all those above it, you’re judging the centre of mass of this new set.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Strange Attraction

Disorder
Energy and Thermal Physics

## Strange Attraction

At home for 5-11 11-14

#### What you need

• Four or more small magnets
• Sticky tape
• A horizontal rod e.g. a pencil
• A flat surface

#### Instructions

1. Fix the rod in place and hang one magnet from it to make a pendulum. (Keep magnets away from toddlers!)
2. Tape the rest down in an equal-sided pattern e.g. a triangle or square
3. With the pendulum very close to the magnets, give it a gentle push. Try changing its starting point, or swinging it harder

#### Results and Explanation

The pendulum will move weirdly, maybe reversing or hanging around one magnet before settling above another. A slight change to how you start it off will make a big difference to where it ends up.
Gravity, the magnetic attractions and pushes on the string work together in complicated ways so that it’s very difficult to predict how the pendulum will swing or where it will settle, even though it’s following the laws of physics.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Sixth-Sense Toy

Force
Forces and Motion

## Sixth-Sense Toy

At home for 5-11 11-14

#### What you need

• Walking toy or object that will slide
• About 50 cm of string
• Rubber band
• A small lightweight bag
• Paper clips and binder clips

#### Instructions

1. Fix a rubber band round the object and tie the string to it
2. Put it on a smooth table and attach a small bag to the end weighted down with paperclips and binder clips to make a small weight
3. With the object about 30 cm from the table edge, try out different weights until it will start to slide if you give it a gentle push

#### Results and Explanation

When you push the object, it will slide till it reaches the edge of the table, then stop. If you're using a walking toy, it should stop walking at the edge.
The force on the toy from the weight acts sideways and downwards, so the string is pulled diagonally, but only the sideways part of it keeps the toy moving forward. As it nears the table edge, the angle of the string changes until there is no part of the force moving the toy forward, so it stops. Some walking toys come with a weight attached, which is why they stop.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Jam Jar Sessions

Mass
Properties of Matter

## Jam Jar Sessions

At home for 5-11 11-14

#### What you need

• Three identical jam jars
• Jam
• Water
• A gentle slope

#### Instructions

1. Fill one jar with jam, another with water and leave the third empty
2. Race all three jars down the slope and see which wins. Try racing them in pairs – the water-filled jar versus the jam-filled jar etc
3. The water-filled jar should be fastest by a slight amount, the jam-filled jar next, and the empty jar slowest

#### Results and Explanation

The force due to the weight of the jars makes them rotate as well as move down the slope. The empty jar’s mass is around its edge, so a lot of the force goes into making this mass rotate.
More of the jam-filled jar’s mass is near its centre so less of the force goes into making this mass rotate. The water in the third jar doesn’t rotate, so all of the force goes into moving the water straight down the slope.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Up next

Force
Forces and Motion

At home for 5-11 11-14

#### What you need

• A long string of beads
• A circular glass container
• A table

#### Instructions

1. Coil the beads carefully into the container so you have layers of circles, one on top of the other
2. Lift the container high. Take the free end of the beads and flick it quickly over the side of the container

#### Results and Explanation

All the beads should “flow” out of the container without help. When they’re moving fast they should even jump higher than the rim of the container.
The weight of the falling beads creates a tension in the chain that acts to pull the rest of the beads in the container up and over the rim. But not all physicists agree on the exact reason!

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bubble Bounce

Properties of Matter

## Bubble Bounce

At home for 5-11 11-14

#### What you need

• Water
• Washing-up liquid
• Bubble wand or rigid loop
• Clean cotton or wool gloves

#### Instructions

1. Mix one part washing-up liquid to three parts water in a cup. Stir and leave it to stand. Use the loop to blow large bubbles.
2. Let one fall onto your bare hand. What happens? Put the gloves on and let one fall on your gloved hand.

#### Results and Explanation

When a bubble hits your bare hand it will pop. But if it falls on your glove you should be able to hold it and bounce it. Bubbles are incredibly thin films of soap, held together by surface tension. Oil or tiny particles on your hand affect the film, breaking it at once, but the soft, clean fibres of your glove do not.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Take the Money

Friction
Forces and Motion

## Take the Money

At home for 5-11 11-14

#### What you need

• A narrow-necked glass bottle
• An old bank note
• A table

#### Instructions

1. Balance the bottle upside down on the bank note.
2. Try whisking the note away without tipping the bottle over. What happens?
3. Gradually roll the note very tightly towards the bottle. Start gently nudging the bottle with the note as you reach it. Keep rolling the note.

#### Results and Explanation

You can remove the note safely. Friction between the bottle and note makes the note pull the bottle with it, but you counteract this by supplying a small force in the opposite direction through nudging it a little as you roll.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Mushrooming marshmallows

Pressure
Properties of Matter

## Mushrooming marshmallows

At home for 5-11 11-14

#### What you need

• Wine saver or coffee saver with pump
• Wine bottle or coffee container
• Marshmallows

#### Instructions

1. Put a handful of small marshmallows into the bottle or container.
2. Put a stopper in the top and pump out as much air as you can.

#### Results and Explanation

The marshmallows should grow to become much larger. When you release the stopper they should collapse to their previous size.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Facing Pressure

Atmospheric Pressure
Properties of Matter

## Facing Pressure

At home for 5-11 11-14

#### What you need

• A balloon
• A little water
• Two plastic cups
• A friend

#### Instructions

1. Blow up the balloon to grapefruit size. Get your friend to wet the rims of the cups and hold them firmly against the balloon, one on each side.

2. Inflate the balloon to normal size then ask your friend to let go of the cups.

#### Results and Explanation

The cups will stick tightly to the balloon without help, and if you draw a face on the balloon the cups it will look like ears.

At first the balloon dips deep into each cup, but it flattens out as you inflate it, taking up less space in the cups, so the air pressure inside them drops. The air pressure outside them is unchanged, so it presses them firmly against the balloon.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Up next

Force
Forces and Motion

At home for 5-11 11-14

#### What you need

• Two large plastic bottles
• A washer
• Water
• Duct tape
• Food colouring

#### Instructions

1. Fill one bottle two-thirds full with coloured water Turn the other upside down, put a washer between them and tape the joint firmly
2. Turn them upside down, let the water flow normally, then swirl the bottles around vigorously

#### Results and Explanation

When you swirl the water, it forms a vortex like a tornado and flows much faster into the lower bottle.

Air from the lower bottle rushes to the top through a hole in the middle of the vortex as the fast-flowing water drains rapidly at the edges.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Solid Visions

Formation of Images
Light Sound and Waves

## Solid Visions

At home for 5-11 11-14

#### What you need

• Stiff acetate or plastic wallet
• Scissors
• Tape
• Smartphone

#### Instructions

1. Using shiny, see-through plastic, cut out four identical pieces and tape them together to make a pyramid 6 cm on each side, with sloping edges 3.5 cm long and a 1 cm hole at the base
2. Search for "hologram videos" on your phone and switch one on – four moving objects will appear. Place the pyramid at the centre of them and turn off the lights

#### Results and Explanation

You should see a moving 3D image appear to float within the pyramid. Some light from each image is reflected off of the pyramid face nearest to it, making it look as if an object is floating inside the pyramid.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Bubbles Squared

Properties of Matter

## Bubbles Squared

At home for 5-11 11-14

#### What you need

• Six pipe cleaners or coated wires
• Six straws
• Scissors
• Soap solution
• Bubble wand

#### Instructions

1. Cut the pipe cleaners in half to make 12 pieces. Twist the ends of three pieces together to make a pyramid shape – make four of these
2. Cut the straws in half to make 12 pieces and slide these over each leg of the pyramids. Twist the ends of each leg together to form a cube
3. Submerge the cube in the soap solution for a few seconds then lift it out and move it gently till you have a horizontal square in the middle. Blow a bubble and drop it onto the square

#### Results and Explanation

The centre becomes a bulging cube!
Attractive forces in the soap mixture pull the film into a shape that minimises distances, creating the central square. These forces also pull the cube in the centre into a more spherical shape.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Matching movement

Charge
Electricity and Magnetism

## Matching movement

At home for 5-11 11-14

#### What you need

• A plastic cup
• A match
• A balloon
• Two 1p coins

#### Instructions

1. Lay one coin flat on a table and balance the other on it vertically. Balance the match on the rim of the upper coin then place the cup over the whole set-up
2. Blow up and tie the balloon then rub it against your hair or jumper. Move the balloon slowly round the cup, without touching it

#### Results and Explanation

The match moves as the balloon does!
Rubbing the balloon transfers negatively charged electrons to it, repelling electrons in the match in a way that causes it to spin.
Friction acts along the whole match when it’s lying flat and stops it moving, but it can spin when it’s resting on a point.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Fruity Floater

Density
Properties of Matter

## Fruity Floater

At home for 5-11 11-14

#### What you need

• An orange
• A deep bowl or container
• Water

#### Instructions

1. Fill the bowl with water and put the orange in it. What happens?
2. Now peel the orange and put it in the water again. What happens this time?

#### Results and Explanation

You should find that the orange floats when its skin is still on, but sinks after you peel it off!
Orange skin is full of tiny air pockets that help make the orange less dense overall than water, so it floats. Removing the skin makes the orange denser than water, so it sinks.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Potato Puncture

Force
Forces and Motion

## Potato Puncture

At home for 5-11 11-14

#### What you need

• A raw baking potato
• A new straw
• A thick glove

#### Instructions

1. Hold the potato with the thumb and forefingers of a gloved hand. Don’t put your hand behind the potato!
2. Make a fist with your other hand, grasping the straw firmly about two-thirds of the way up
3. Use a fast, thrusting movement to force the straw into the potato

#### Results and Explanation

The straw should go in, but if you try to twist it in slowly, it doesn’t work.
The rim of the straw has a very small surface area, so you have a small amount of potato to displace and your sharp movement delivers a large force on it in a brief instant, which works much better than a slow twist.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Dry Times

Atmospheric Pressure
Properties of Matter

## Dry Times

At home for 5-11 11-14

#### What you need

• Newspaper
• Water
• Bucket or deep bowl
• Plastic or glass container

#### Instructions

1. Fill the large bowl about two-thirds full with water. Scrunch up the newspaper and stuff it firmly into the container
2. Plunge the container straight down into the water, wait about 20 seconds, then lift it straight out again without tilting or turning it

#### Results and Explanation

When you take the newspaper out, it is completely dry!
Water cannot fill the container because of the air trapped inside it. The air gets squashed a little, but the air pressure is enough to push against the water so it doesn’t get into the container or touch the paper.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Pinhole Peeking

Formation of Images
Light Sound and Waves

## Pinhole Peeking

At home for 5-11 11-14

#### What you need

• 10cm x 10cm piece of card
• Aluminium foil
• Sticky tape
• Pin or needle
• Computer or phone screen

#### Instructions

1. Cut a shape about 3cm square from the card, tape foil across the gap and make a tiny pinhole in the foil.

#### Results and Explanation

When you hold the card close to you and look through the pinhole at some writing on the screen, it should be magnified and sharper, though it will be dimmer.
The closer you are to an object, the larger the image it makes on the back of your eye, but get too close and the image will be fuzzy, because your eye does not bend all the light rays coming in by enough to focus them into a sharp image.
A pinhole cuts down the spread of light rays entering your eye so your lens focuses the rays coming through a smaller area and a sharp image forms on the back of your eye.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Speeding Spinner

Circular Motion
Forces and Motion

## Speeding Spinner

At home for 5-11 11-14

#### What you need

• Two ball bearings
• Large rubber band
• Glue
• Two paper clips

#### Instructions

1. Wind a paper clip into a spiral, tie one end of the rubber band to it and glue it to a ball bearing. Do the same with the other end of the band
2. Holding one ball bearing, rotate the other until the band is wound up. Keeping the ball bearings together, drop them onto a smooth surface

#### Results and Explanation

The ball bearings spin, speeding up as the band unwinds. Then the band contracts, winding up the other way. The cycle repeats, with the bearings spinning in the opposite direction.
The twisting in the band makes both bearings turn, so they roll round. When the band has untwisted they're moving so fast that they overshoot, making the band wind up the other way, which slows them to a pause.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Strength in Sand

Force
Forces and Motion

## Strength in Sand

At home for 5-11 11-14

#### What you need

• Piece of tissue 20 cm square
• Kitchen roll tube
• Sand
• A stick, e.g. dowel rod
• Rubber band

#### Instructions

1. Cover one end of the cardboard tube with the tissue paper. Hold it in place tightly with the rubber band
2. Poke through the tissue with the rod – it will tear. Start again with a new piece of tissue and fill the tube three-quarters full with sand. (Salt also works well.) Try poking the rod through again

#### Results and Explanation

The rod just won’t tear through the paper!
As you push the rod, the grains of sand are pushed away from it in all directions. The sand forms “arches” that push against the sides of the tube so that the entire force does not push down on the tissue.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Seeing Circles

Formation of Images
Light Sound and Waves

## Seeing Circles

At home for 5-11 11-14

#### What you need

• Blu Tack
• String about 1 metre long
• Two 2p coins
• Old pair of sunglasses

#### Instructions

1. Stick the 2p pieces together with Blu Tack and tie the string to it to make a pendulum. Watch from about 2m away as it’s swung from side to side in a straight line
2. Break the sunglasses in half at the nose, and put a lens in front of one eye, but look at the moving pendulum through both eyes. Swap the lens to the other eye and watch again

#### Results and Explanation

You'll see the pendulum moving in a circle or ellipse, instead of a straight line. When you put the lens in front of your other eye, you’ll see it moving in a circle in the opposite direction.
Sunglasses block some light, delaying signals from your eye to your brain. Normally you don’t notice, but when you cover only one eye, that eye sees the pendulum delayed with respect to what the other eye sees, so your brain thinks it’s moving in a circle.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Egg-stra Tough

Force
Forces and Motion

## Egg-stra Tough

At home for 5-11 11-14

#### What you need

• A raw egg
• Plastic bag or glove

#### Instructions

1. Make sure the egg has no hairline fractures and that your hand is free of objects such as rings
2. Squeeze the egg evenly from different angles to try to break it, without using your nails. Wear a plastic bag or glove on your hand if you’re worried about mess

#### Results and Explanation

Believe it or not, you can’t break it by squeezing it!

An egg’s arched shape makes its structure as strong as possible, so applying force to the ends or sides spreads the force out, making the shell stretch before it can break. But a sudden force applied at one small point will break it.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Footprints on the Sand

Volume
Properties of Matter

## Footprints on the Sand

At home for 5-11 11-14

#### What you need

• Bottle full of dry sand
• Clear balloon
• Funnel
• Water

#### Instructions

1. Inflate the balloon and stretch it over the neck of the bottle. Invert the bottle so the sand pours into the balloon. Pinch the balloon shut then gradually let the air out of it.
2. Pour water through the funnel into the balloon until all the sand is wet and there’s a little water in the neck. You’ll need to squeeze and tap the balloon and stretch its neck to get the water in.

#### Results and Explanation

When you squeeze the balloon the level of water in the neck goes down instead of up. The volume of the wet sand expands when you squeeze it and the water flows in to fill the gaps between sand grains.

Squeezing the sand causes each layer of grains to shift and the layer below to move the opposite way. These tiny movements create gaps in the bulk of the sand which the liquid can fill.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

### Instant Snow

Phase Change
Properties of Matter

## Instant Snow

At home for 5-11 11-14

#### What you need

• Filtered water
• Plastic water bottles
• Freezer

#### Instructions

1. Fill two plastic water bottles with filtered water and leave them on their sides in the freezer.
2. After two to three hours take one bottle out to test it. Slam it on the counter once and see if anything changes.

#### Results and Explanation

You should see crystals of ice form at the top of the bottle and flurry downwards quickly.

Supercooled water is water that is liquid below its freezing point. When you slam the bottle it causes ice crystals to move and others to grow in a chain reaction.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.