# Lab: Reaction Time

## Science Lab: Reaction Time

#### A. Question:How quickly can someone react to a visual stimulus?

B. Materials:
1. two people
2. desk or table
3. 30-centimetre ruler
4. pen
5. paper

C. Procedure:
1. One person sits by a desk, resting the heel of a hand on the edge of the desk with the thumb and forefinger stretched apart.
2. The other person holds a 30-centimetre ruler so that the zero end is even with the thumb and forefinger of the seated person.
3. The first person watches the bottom end of the ruler.
4. The second person drops the ruler.
5. The first person brings thumb and forefinger together to catch the ruler.
6. Note where the ruler is caught and measure the distance from the bottom of the ruler to the top of the thumb.
7. Repeat this experiment four times, recording the results each time.
8. Calculate the average time for the five trials.

#### D. Observations and Results: 1. Make a chart showing the time for each trial. 2. Write a mathematical equation showing how you determined the average amount of time for all five trials.

Distance  and Reaction Times
1 cm =  0.05 sec.                11 cm =  0.15 sec.
2 cm =  0.06 sec.                12 cm =  0.16 sec.
3 cm =  0.08 sec.                13 cm =  0.16 sec.
4 cm =  0.09 sec.                14 cm =  0.17 sec.
5 cm =  0.10 sec.                15 cm =  0.18 sec.
6 cm =  0.11 sec.                16 cm =  0.18 sec.
7 cm =  0.12 sec.                17 cm =  0.19 sec.
8 cm =  0.13 sec.                18 cm =  0.19 sec.
9 cm =  0.14 sec.                19 cm =  0.20 sec.
10 cm =  0.14 sec.            20 cm =  0.20 sec.
25 cm = 0.23 sec.                30 cm =  0.25 sec.

E. Conclusion:
1. Make some hypotheses about why the times varied between trials.
2. Repeat the trials using your other hand to catch the ruler.
3. Discuss the results with others in your class to see if there are any differences due to gender, hand dominance, musical ability, athletic abilility, age or any other factors.
4. Try the experiment again at a different time of such as first thing in the morning or last thing at night. Observe any differences in your reaction time.