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.