How fast are you? Have you ever measured your reaction time? There’s a really cool way to test reaction times using a simple ruler.

Reaction time is a measurement of how quickly an organism (in your case a human) can respond to a particular stimulus. For example if you touch something very hot, there is a slight delay between the moment you touch it and moving your hand away, because it takes time for the information to travel from your hand, to your brain where it is processed and then it tells you to respond.

The reaction time test

What you need
30cm ruler
Pen and Paper
Friends

How to do it.

• Hold the top of the ruler with your arm stretched right out in front of you.
• Ask your friend to put their thumb and index finger slightly open at the bottom of the ruler, with the ruler between their fingers but not touching it!

• Drop the ruler and get your friend to catch it between their fingers and record the measurement on the ruler where they catch it.
• Repeat for all your friends and let each person have three attempts.
• The one with the fastest reaction time is whoever catches the ruler at the lowest measurement. The sooner the ruler is caught the the quicker you are!

 How does it work?
You see that the ruler has been dropped and your eyes send a signal to your brain, which sends a signal to the muscles in the arm and hand to tell them to catch the ruler. Your body is very clever and these signals travel extremely quickly. Your reaction time depends on the time taken for your bodies super fast signals to travel between your eye, brain and hand.