When the screen changes to green, click it. Then you will be able to see your reaction time. After a few seconds, get ready to click the screen again, as it will change to red this time. The average reaction time to a visual stimulus is 250 milliseconds … see if you can beat that :) *A study about the effect of color on reaction time*
All credit goes to @punisaa556! Also thanks to myself, for thinking of this awesome project idea ;)!