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This week's LabZone activity
July 25, 2007
Think Quick!
Objective
Measure the reaction time of people by catching a metric ruler.
Introduction
Has anyone ever said, "Think fast!" and then thrown something at you? How quickly or slowly you respond is called your reaction time. Your reaction time will be measured by how long it takes for your eyes to tell your brain that the ruler is falling and then for your brain to tell your fingers to catch it. The falling ruler is called a stimulus and the attempt to catch it is called a simple reaction. The simple reaction time is the time it takes to react to a simple stimuli - or small change in the environment.
In this experiment, you will measure your reaction time by catching a metric ruler with your fingers. After you catch the ruler, you will convert your measurement in centimeters into a reaction time measured in seconds. To do this, you will need to use the following reaction time table (from Brody, 1987, 147):
Drop
Distance |
Reaction
Time |
Drop
Distance |
Reaction
Time |
Drop
Distance |
Reaction
Time |
Drop
Distance |
Reaction
Time |
| (inches)
| (cm) |
(ms) |
(inches)
| (cm) |
(ms) |
(inches)
| (cm) |
(ms) |
(inches)
| (cm) |
(ms) |
| 1.0 |
2.5 |
72.0 |
7.0 |
17.8 |
190.5 |
13.0 |
33.0 |
259.6 |
19.0 |
48.3 |
313.8 |
| 2.0 |
5.1 |
101.8 |
8.0 |
20.3 |
203.6 |
14.0 |
35.6 |
269.4 |
20.0 |
50.8 |
322.0 |
| 3.0 |
7.6 |
124.7 |
9.0 |
22.9 |
216.0 |
15.0 |
38.1 |
278.8 |
21.0 |
53.3 |
329.9 |
| 4.0 |
10.2 |
144.0 |
10.0 |
25.4 |
227.7 |
16.0 |
40.6 |
288.0 |
22.0 |
55.9 |
337.7 |
| 5.0 |
12.7 |
161.0 |
11.0 |
27.9 |
238.8 |
17.0 |
43.2 |
296.9 |
23.0 |
58.4 |
345.3 |
| 6.0 |
15.2 |
176.4 |
12.0 |
30.5 |
249.4 |
18.0 |
45.7 |
305.5 |
24.0 |
61.0 |
352.7 |
To measure your reaction time, ask a friend for help. He or she will drop the ruler for you and you will catch it. To get better data, you should take three different measurements, each called a trial. You will combine the data from the trials together by taking an average. Then you can repeat those trials for a friend, measuring his or her reaction times. After recording each other's reaction times, compare them. Then you can ask other people to volunteer, too!
Experimental Procedure and Additional Information
Used with permission. Copyright © 2002-2007 Kenneth Lafferty Hess Family Charitable Foundation. All rights reserved.
Sohn, Emily. 2007. Video game violence. Science News for Kids (Jan. 24). Available at http://www.sciencenewsforkids.org/articles/20070124/Feature1.asp .
______. 2005. Monkeys in the mirror. Science News for Kids (Aug. 10). Available at http://www.sciencenewsforkids.org/articles/20050810/Note2.asp .
ScienceFairZone
Keeping Up
http://www.sciencenewsforkids.org/articles/20070207/LabZone.asp
For more science project ideas, go to http://www.sciencebuddies.org/mentoring/areas_of_science.shtml.
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