Kids, Try this at home! This activity measures your reaction time, which is the amount of time it takes for your body to react to a stimulus. When a stimulus, such as a noise, something visual, or something that you touch, is presented to your body, your sense organs (eyes, nose, skins, ears, mouth) send a message to your brain. Your brain has to process the information and send another message to your body, telling it to react. The messages travel very quickly and are measured in milliseconds (there are 1,000 milliseconds in a second). Your reaction time in this activity depends on your vision and the speed that the visual signal travels to your brain, and immediately your brain sending a message to the muscles in your hand.
Materials:
A ruler, a piece of paper, a pencil, two people
Instructions;
- Person A: Standing up, take the ruler and hold it at the top.
- Person B: Sitting on a chair in front of the other person, put your hand below the ruler with your thumb on one side and your fingers on the other, without touching the ruler. Be ready to grab it when the other person drops it.
- Person A: Tell Person B that you’re going to drop the ruler sometime in the next ten seconds. (Don’t tell Person B exactly when you are going to drop it!)
- Person B: Get ready to grab the ruler as quickly as possible. The faster you react and grab the ruler, the less time the ruler will be falling.
- Person A: Drop the ruler.
- Person B: Grab the ruler.
- Both people note which inch/centimeter Person B grabbed the ruler (where the thumb and other fingers are on the ruler); for example, forty-three centimeters (cm). Use the table below to convert the distance into reaction time.
- Repeat five times, changing the time that Person A waits before dropping the ruler.
Distance |
Time |
6” (~15 cm) |
0.17 sec (170 ms) |
8” (~20 cm) |
0.20 sec (200 ms) |
10” (~25.5 cm) |
0.23 sec (230 ms) |
12” (~30.5 cm) |
0.25 sec (250 ms) |
17” (~43 cm) |
0.30 sec (300 ms) |
24” (~61 cm) |
0.35 sec (350 ms) |
31” (~79 cm) |
0.40 sec (400 ms) |
39” (~99 cm) |
0.45 sec (450 ms) |
48” (~123 cm) |
0.50 sec (500 ms) |
Think about this:
Reaction time can change when a person practices, when a person is tired, and according to their age or gender. Try the activity again, but this time instead of grabbing the ruler, catch the ruler by clapping with both hands. Does that change your reaction time? When you try it with people of different ages, does that change the reaction time? Can you think of some activities when you need a short reaction time? For example, playing basketball, or driving a car. When happens if you don’t react in time?
The information for this article came in part from the website:
http://faculty.washington.edu/chudler/chreflex.html
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