What to do: Begin by making sure the red side of the switch is pushed. Plug the electrical cord into the wall. Place the metal solenoid pole, located at the top of the meter stick, into the hole at top of the exhibit. Place your open hand level with the bottom of the meter stick, ready to catch the falling stick (see photograph A). Have a friend flip the switch to the green side. Grab the stick as fast as you can. Warning! If you have sensitive eyes, put on the provided eye wear. To test reactions to different stimuli, you can try putting on ear muffs, or else you can just close your eyes and listen for the beeper. When you have completed the reaction time test, make sure the cord is unplugged and the switch is on red.

          What is happening: When the cord is plugged in and the switch is on the green side, the electrical current is running through the 6 volt transformer and up to the pole solenoid. The solenoid then creates a magnetic field which holds the metal pole up. As your friend flips the switch, the current to the solenoid shuts off, dropping the ruler, and simultaneously, the current then runs towards the light, illuminating it. As the light illuminates, the light sensitive beeper sounds.

          The Purpose: Reaction time is the lapse of time between stimulation and the beginning of response. In other words, reaction time is the time it takes the brain to recognize an event, decide how to respond, and then command the muscles to react to the event. This project tests one’s reaction time as different senses are stimulated.