How fast are you?

Think you're fast? Try this clever little trick to work out how fast your reaction time is – and there is no need for high precision clocks!

You will need:

A ruler, or metre stick if you have one
Some volunteers who are prepared to be tested…

What to do:

Hold the ruler at one end, so that the zero is at the bottom, hanging down between your volunteer's thumb and forefinger.
Tell your volunteer that you will drop the ruler some time within the next 5 seconds and their job is to close their thumb and forefinger to catch it as fast as they can after it starts dropping.
Drop it…and record where they managed to catch it. Keep testing them and anyone else wants to try!

What's going on:

Here's a very rough guide to the reaction times taken to grab the ruler at different distances down the ruler…

5 cm = 0.10 seconds
10 cm = 0.14 seconds
15 cm = 0.17 seconds
20 cm = 0.20 seconds
25 cm = 0.23 seconds
30 cm = 0.25 seconds
43 cm = 0.30 seconds
60 cm = 0.35 seconds
80 cm = 0.40 seconds

This experiment measures how long it takes for visual information to reach the brain, and for the brain to process the information, and send a command to your hand to say 'grab NOW!!!'

Whatever time you recorded, you must admit it's pretty speedy considering everything that has to happen inside the brain - plus the time it takes the 'grab now' message to travel from Brain Central out to the Fingers Operational Depot!

You can even take the experiment further; try comparing boys and girls, people of different ages, and you can even turn the lights down…