Imagine you are driving a bike at a very high speed. There is another car in front of you. The car in front of you suddenly brakes. You also brake so that you don't crash into the car.
How much time has passed between the car braking and you applying brakes on your bike? This is called reaction time. Your eyes see the car braking and inform your brain that the car has braked. Your brain then decides that you must also brake, and informs your fingers to apply the brakes.
Different people have different reaction times. Do you want to calculate yours? Let's see how to do it in this module!