Can you catch a falling meter stick before it slips past your fingers? Reaction time (how fast you respond to something) varies from person to person. You build a frame that holds and drops a meter stick at a random moment. Each person sits with their thumb and finger open. When the stick falls, they grab it as fast as they can. You measure how far the stick fell in centimeters. You test equal groups of boys and girls to compare their average reaction times. The results may not match what you expect.