Reaction times


- To measure the reaction time for individual students for both left and right hands and feet.

- Working in pairs student "A" holds a ruler against the wall as shown on the right. Student "B" hold his finger 1 cm from the ruler as shown. Without warning, student "A" releases the ruler. Student "B" reacts by pressing on the ruler to stop its fall. Click to see a 120kb video
- Record the fall distance for five trials with both hands and feet.
- Use the graph below to determine the reaction time. Click to see how


Trial results (cm)
Average reaction time (s)

Class average time

Favoured hand
Non-favoured hand
Favoured foot
Non-favoured foot


1) Comment on any differences between your favoured and non-favoured hand and foot.

2) Comment on any differences between your hands and your feet.

3) How do your reaction times compare with the class average?

4) Are left footed people at a disadvantage when applying the brakes in a car? Give reasons.

Change the experimental technique to investigate the effect on reaction time of:

- fatigue;
- caffeine;
- mild exercise.