Reaction Times

Reaction times vary from person to person

Everyone’s reaction time is different, but a typical reaction time is between 0.2 and 0.9 s. This can be affected by tiredness, drugs or alcohol. Distractions can also affect your ability to react

You can measure reaction times with the ruler drop test

You can do simple experiments to investigate your reaction time, but as reaction time are so short, you haven’t got a chance of measuring one with a stopwatch

One way of measuring reaction times is to use a computer-based test. Another is the ruler drop test:

• Sit with your arm resting on the edge of a table. Get someone else to hold a ruler so it hangs between your thumb and forefinger, lined up with zero. You may need a third person to be at eye level with the ruler to check it’s lined up
• Without giving any warning, the person holding the ruler should drop it. Close your thumb and finger to try to catch the ruler as quickly as possible
• The measurement on the ruler at the point where it is caught is how far the ruler dropped in the time it takes you to react
• The longer the distance, the longer the reaction time
• You can calculate how long the ruler falls for because acceleration due to gravity is constant, roughly 9.8m/s
• It’s pretty hard to de this experiment accurately
• Make sure it’s a fair test-use the same ruler and same person
• You could try to investigate some factors affecting reaction time
• Do lots of repeats and calculate mean reaction time with distractions, which you can compare to the mean reaction time without distractions

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