Response Time: An Introduction to the Nervous System
Student Content Outcomes
; Summarize the organization of the nervous system
; Trace the sensory and motor pathways in a reaction to a stimulus
; Explain the effects of distractions on somatic motor response
; Evaluate individual reaction time
Model 1: Exploration of Stimulus-Response Time
1. Collect a meter stick and find a desk.
2. Support your arm on the edge of a desk so that you cannot move it down.
3. Make sure your hand extends over the edge of the desk.
4. Hold your thumb and index finger approximately 2.5 cm apart.
5. Have your partner hold the meter stick so that the 0 end of the meter stick is even with the
top of your index finger and thumb.
6. Have your partner drop the stick (Do not countdown or say anything).
7. Catch the stick without moving your arm and hold so that you can measure the distance.
8. Measure and record the distance to the top of your index finger in data table #1.
9. To approximate the reaction time in seconds, divide the distance in cm by 22.1 and record
calculated reaction times in table #1.
10. Repeat this procedure two more times for each student in the group, then determine an
average for both distance and reaction time.
11. Repeat the process with each of your partners, and record their data in their Table #1.
12. Complete Table #2 by sharing data with your partners in your group.
Table #1 Table #2
Trial # Distance (cm) Reaction time (sec) Name Average distance Average reaction
(cm) time (sec)
Use the data in Table 2 to answer the following questions:
Answers to all questions should not be taken literally. Teachers may delve deeper into answers per course requisites. For example, teachers may wish to cover auditory, visual or other CNS centers and pathways, spinal cord pathways, introduction of left/right cross over points along with damage (stroke, physical trauma, etc.). Further extension could include autonomic, action potentials, neuromuscular junction, etc.
1. Within your group, who had the fastest average reaction time? Slowest reaction time?
Answers based on student data
2. Calculate the difference between the fastest and slowest reaction times in your group.
Answers based on student data
3. Why do you think there was a difference between the individual with the fastest average reaction time and the individual with the slowest average reaction time in your group?
Subject anticipation, athletic ability, distraction, lack of sleep, etc. A good website for further research on reaction times is: http://biology.clemson.edu/bpc/bp/Lab/110/reaction.htm
4. A hundred dollar bill measures 15.6 cm long. Would anyone in your group be able to grab a dollar bill before it slips through their fingers? Cite evidence from your data above in your answer?
Answer based on student data, most likely no.
5. List 3-5 basic processes of the nervous system that occur in your body when you complete step 7 of the procedure.
Answer should focus on the pathway from visual stimulus to central processing to skeletal muscle response.
Model #2: Basic organization of the nervous system: