And introducing the .....family challenge....get the adults thinking as well!

 Ruler drop

Here is an experiment you can use to test your reactions.
Ask a friend to hold a ruler by the end, above your hand. Open your hand below the ruler and be ready to catch it. Your friend will drop the ruler without saying when they're going to let go. Catch the ruler as fast as you can after it's been dropped.
The pictures below show this experiment being carried out:



Record the level (in centimetres) at which you caught the ruler, and repeat the experiment several times. If you have quick reactions, the ruler will not have travelled far when you catch it.

Taking only one measurement in either of these experiments will not give you a reliable, accurate measure of speeds of reaction that could be used to rank a group of people.

Decide how many measurements you will take, and what you will do with them to provide an accurate measure of reaction speeds. Make sure you can justify your decisions.
 

Here are some questions you might like to consider:

• I think I respond more quickly with my right hand than with my left - are you the same?
• Do your reactions vary depending on the time of day or the sort of thing you are being asked to react to?
• Do your reactions improve with training/practice?
• Do boys react more quickly than girls?
• Do young people react more quickly than older people?
• What else do you think affects people's reaction times?
• Can you think of other experiments you could do to test your reactions?

Test any hypotheses you come up with.