Reaction Time
Purpose: To measure your personal reaction time.
Discussion:
Reaction time is the time interval between receiving a signal and acting on it – for example, the time between a
tap on the knee and the resulting jerk of the leg. Reaction time often affects the making of measurements.
Example: using a stopwatch to measure the time for a 100-m dash. The watch is started after the gun sounds
and is stopped after the tape is broken. Both actions involve reaction time.
Materials:
Centimeter Ruler
Data table
Calculator
A partner
Procedure:
1. Have your partner drop a centimeter ruler between your fingers. Catch it and note the number of
centimeters that passed during your reaction time.
2. Repeat step one 5 times. Record distances in table 1.
3. Then calculate your reaction time using the formula
D = ½ gt2
where d is the distance in centimeters.
(For d in m, t in s, we use g = 9.8 m/s2)
Record times in table 2
4. Trade jobs and repeat steps.
5. Report your reaction times to Mr. Foster.
Data:
Table 1:
D1 (m)
Table 2:
t 1 (s)
D2 (m)
t 2 (s)
D3 (m)
t 3 (s)
D4 (m)
t 4 (s)
D5 (m)
t 5 (s)
Avg.
Reaction
time (s)