What speed?

What the Activity is for

Calculating speed.

The purpose of this activity is for pupils to take measurements and to practise using the relationship:

speed = distanceduration

Although the distance travelled by each object and the time taken is different, pupils should appreciate that the calculated average speed allows the motions of different objects to be compared.

What to Prepare

A circus of activities for measuring the average speed of different objects. Each circus station will need a metre rule and a stop clock and various objects which might include:

• moving clockwork, battery and friction-drive toys
• trolleys on an incline; bubbles rising in a water column; beads falling through a liquid column; paper helicopters

Aim for interesting moving objects, with a wide range of speeds.

What Happens During this Activity

In groups of two or three, pupils measure the time taken by different objects to travel different distances and use the relationship to calculate the average speed of each object.

At each station you might give instructions on what to do, what to measure and what to record. However it might be better to leave some space for group discussions on how best to carry out the measurements. By displaying the relationship beside each station you will reinforce the task in hand.

Pupils can then use calculated speeds to rank the objects in order of fastest to slowest, even though they did not travel for the same distance or length of time. A suitable end point might be to display results of measurements from each group. Is there a high level of agreement between the groups? If not, why not? Any ideas?