Name______LAB #

Class______Date_____

RESPONSE TIME LAB

Purpose: You determine your response time to different stimuli.

Materials: Metric ruler

Procedure:

1. Have your partner hold the top end of the ruler (near the 30cm mark).

2. Place your thumb and first finger close to but not touching the bottom end of the ruler (near the 0cm mark).

3.When your partner gives the signal (stimulus) and drops the ruler, try to catch it as fast as you can. Mark the distance the ruler fell on the correct data table. Repeat three trials for each signal (stimulus).

Stimuli / Sense Organ Used
Part 1 / Movement of the ruler and “Now” / Eyes and Ears
Part 2 / Movement of the ruler / Eyes
Part 3 / “Now” / Ears

4. Using the conversion table, record the time in seconds the ruler fell for each trial. Record your response time on your own lab.

Distance ruler fell (cm) / Time in seconds / Distance ruler fell (cm) / Time in seconds
2 / .06 / 16 / .18
4 / .09 / 18 / .19
6 / .11 / 20 / .20
8 / .13 / 22 / .21
10 / .14 / 24 / .22
12 / .16 / 26 / .23
14 / .17 / 28 / .24

**If the ruler falls to the ground try it one more time, if it still fell to the ground that second try record the result as “Fall” and the time is .26 seconds

Part 1: Eyes and Ears

Trial / Distance Ruler fell (cm) / Time in seconds
1 /
2
3 /
Total
Average

Part 2: Eyes Only

Trial / Distance Ruler fell (cm) / Time in seconds
1
2
3
Total
Average

Part 3: Ears Only

Trial / Distance Ruler fell (cm) / Time in seconds
1
2
3
Total
Average

*Round ALL averages to the nearest thousandths place! .

(That’s three decimal places)

Questions and Conclusions:

1. Describe how an organism’s survival depends on its ability to respond.

2. A change in the environment that causes an organism to respond is called a ______.

3. Under which stimuli were you able to respond the fastest?

4. List all six characteristics of living things.

5. Make a bar graph to show your results. You only have to graph the averages for each part. Include the following: Key, Title, Axis labeled with the units, and color.

6. What is the independent (manipulative) variable? (Give the example from this experiment)

7. What is the dependent (experimental) variable? (Give the example from this experiment)

8. List 4 things that should be held constant.

9. Which part acts as your control? WHY?

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