Activity 1

REACTION TIME

 

Reaction time is the amount of time required for an individual to respond voluntarily to a sensory stimulus. The ability to react quickly when confronted with danger has saved many of us from injury on many occasions.

 

The ultimate limitation to the speed of physical reactions is the speed at which a nerve impulse travels along the appropriate neural pathways. In humans, the nerve conduction velocity varies form 0.5 m/sec to 120 m/sec, depending upon the diameter of the nerve fiber involved. Reaction times, however, require longer time periods; for example the average reaction time for a visual stimulus is 200 - 2550 ms; for hearing, 150 &endash; 200 ms; for the sense of touch, 130 &endash; 170 ms.

 

PROCEDURE

 

Now you are going to use your knowledge of science, math and language arts to investigate reaction time. You may use a dictionary and/or textbook to look up words you do not understand. You may use a calculator to do your computations.

Remember that if you do not understand a question or problem the first time you read it, it is helpful to read it again. Always do your best thinking and your best writing.

 

1. One partner (Subject) sits upright in a chair.

2. The other partner (Releaser) stands facing the partner and holds the "release" end of the ruler higher than eye level of the partner (Subject) between the thumb and index finger.

3. The partner (Subject) positions his thumb and index finger over the "thumb line" of the ruler. The space between the subject's thumb and index finger should be approximately 3 cm.

4. When, ready, the partner (Subject) must tell the releaser to start. The partner (Releaser) may then drop the ruler at any time within the following 10 seconds. It must not be thrown downward. At not time during the test may the partner (Releaser) look at the subject.

5. The partner (Subject) tries to catch the ruler between his thumb and index finger as soon as it begins to fall.

6. When the ruler has been caught, the point corresponding to the center of the partner's (Subject) thumbnail should be noted. This point represents the number of milliseconds that passed before it was caught.

7. Record ten measurements on the Baseline Trials sheet. Then, find the average (mean) of the measurements. The average is the partner's reaction time.

 

Baseline Trials (Activity 1)

 

Name

Trial

Measurement

1

2

3

4

5

6

7

8

9

10

Sum =

Average =


Activity 2

Based on the data of this investigation, how did you find the mean? Explain what steps you used.

 

 

 

 

 


 Activity 3 Exercise Study

 

1. The subject should exercise for 10 minutes and record the time of starting.

1. Measure reaction times in the same manner at 1, 5, 10, 15 minutes after exercising.

2. Each student should answer the questions at the bottom of the data sheet in complete sentences.

 

 

Exercise and Reaction Time (Activity 3)

Name

Trial

1 minutes

5 minutes

10 minutes

15 minutes

1

2

3

4

5

6

7

8

9

10

Sum =

Average =

 

1. Compare the average baseline reaction time with the average exercise reaction time.

 

 

 

2. Does the effect of exercise wear off?

 

 

 

3. Describe how exercise effects reaction time?

 

 

 


 Activity 4 Caffeine Study

 

1. The subject should drink a cup of cola and record the time of starting.

2. Measure reaction times in the same manner at 5, 15, 25, 35 minutes after drinking the cola.

3. Each student should answer the questions at the bottom of the data sheet in complete sentences.


Caffeine and Reaction Time (Activity 4) chart

Name

Trial

5 minutes

15 minutes

25 minutes

35 minutes

1

2

3

4

5

6

7

8

9

10

Sum =

Average =

 

 

1. Compare the average baseline reaction time with the average caffeine reaction time.

 

 

 

2. Does the effect of caffeine wear off?

 

 

 

3. Describe how caffeine effects your reaction time?

 

 

 

 


Activity 5

 

You have worked like a scientist to collect, record and analyze data. What variables were important in these investigations? Why is the control of variables important to the scientific procedure?

 

 

 

 

 

 

 

 


Activity 6

 

Based on the data of this investigation, what conclusions can you make?

 

 

 

 

 

 

 

 

Activity 7

 

Do you think it is advantageous for humans to have quick reaction times to stimuli? Explain your answer.

 

 

 

 

 

 

 

 

Activity 8

 

Did you know that signals between neurons move at speeds up to 300 feet per second? That is quite fast! This function would not be possible without the nervous system. The nervous system keeps you alive and includes your brain, nerves, and spinal cord. Think about, how could you survive without these important organs? You will learn how important the nervous system is in this task.

There are three divisions of the nervous system. They are the central nervous system, the peripheral nervous system, and the autonomic nervous system. First, lets start with the central nervous system.

The central nervous system is made up of two organs: the brain and the spinal cord. The nervous system is responsible for issuing nerve impulses and analyzing/identifying sensory data. It functions as a switch that controls the activities of the entire nervous system.

The peripheral nervous system carries all the messages sent between the central nervous system and the body. The peripheral nervous system consists of 12 pairs of nerves that begin in the brain and 31 pairs of nerves in the spinal cord. These cranial and spinal nerves carry messages to and from points in the body.

The autonomic system is part of the peripheral nervous system. It regulates functions such as breathing, and does not use the brain. It helps maintain stability inside the body.

The central nervous system also helps other systems work. It is related to them by its ability to regulate and coordinate functions of all the systems in the body. It especially helps the muscular, circulatory, endocrine, and skeletal systems.

 

 

Draw and Label Figure 8-2 below and Design a Sequence chain using Figure 8-2 information on pages 242 and 243 in Science Interactions Course 2.

 

 

 

 

 

Activity 9

 

Give an example of a stimulus you encounter everyday and your response. What role does your nervous system play in this situation?

 

 

 

 

 

 

Activity 10

 

After a severe accident, a person can talk and write, but has to learn to walk all over again. What parts of the nervous system were probably affected by the accident? What parts of the nervous system were not affected?

 

 

 

 

 

 

Activity 11

 

Think about what you have learned throughout these tasks about the central nervous system. Go back to the Motivational Activity, the K-W-L Chart. On your own complete the "L" column of the chart

 

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