Unit Name: Science in Sports
Lesson Name: The Nervous System (Reaction: Voluntary and Involuntary)
Lesson Objectives: To introduce the idea that nerves carry messages throughout
the body and there is some delay associated with this process (reaction time)
Target Age Group: 2-4 graders
Materials Needed: At least one foot rulers; hammers for hitting the knees
Introduction/Lecture:
We talked before about muscles and using your muscles in sports to say hit a ball (in
baseball). How do we know when to hit the ball?
We see the ball, etc.
How does what the eye see get through to the muscle? Where does this message travel
through the body?
Eye sees the ball. The message is carried by special cells in the body (Does
anyone know what these cells are called? … nerve cells.
Message goes to the central nervous system… brain and spine
Brain or spine process what to do
Nerve cell carries message to the muscles
Muscles contract and you swing at the ball.
This process is made possible by the nervous system; which we’re going to talk about the
nervous system and how it relates to sports.
90mph fast ball in baseball takes about 0.5 seconds to reach home plate
usually the batter has to react at least within 0.25 seconds to hit the ball successfully
http://www.exploratorium.edu/baseball/reactiontime.html
Parts of the nervous system
Nerves
Spinal Cord
Brain
(Central nervous system is brain and spine)
Neuron:
Cell body: contain the organelles that keep the cell alive
Dendrites: receive information from another cell
Axon: conduct messages away from cell body
Three types of neurons:
Sensory neuron: connect sensory organs to central nervous system
(what are sensory organs? Give examples… like eyes, ears, tongue?)
Motor neuron: connect central nervous system to muscles
What muscles?
Interneurons: connect neurons with neurons
Voluntary versus involuntary reaction
In voluntary reaction, you require a conscious processing of information. (signal
goes all the way to brain and we actually think about what to do and then control the
muscles with thinking)
What are some examples of voluntary reaction??
In involuntary reaction, you react without thinking.
What affects reaction time? Age.. how awake you are, how much you practice? What
are other examples of impairments? (fatigue, dizziness, etc)
Reaction time versus age: shortens from infancy into late 20s and then gets longer to the
50s and 60s
Does this explain why most athletes are pretty young? 20s-30s
Mean age of gymnasts is 14-15
Why? Due to slower nervous speed; also old people tend to be careful
Does practicing make you faster at reacting? (Yes.. theoretically up to a certain point)
Now do worksheet…
At the end, come back and look at results…. Who got better? Tutor versus kid reaction
time?
Distance to time conversion is t = sqrt(2*d/a) d is distance in cm
Nervous System and Reaction Time Worksheet
Voluntary Reaction
A batter has less than 0.25 seconds to react to a fast ball. How fat can you react?
Instructions: One student hold a ruler in the air with 0 inch marking closer to the ground.
A second student holds thumb and forefinger around the ruler at the 0 inch mark. The
first student drops the ruler without warning and the second student tries to catch it as fast
as possible. Repeat 10 times and record the measurement where the ruler is caught.
Draw the path through your body that the signals travel that allow you to catch the ruler.
Convert the distance dropped to a reaction time using the table:
distance dropped
Reaction time
2 inches
0.10 seconds
4 inches
0.14 seconds
6 inches
0.18 seconds
8 inches
0.20 seconds
10 inches
0.23 seconds
12 inches
0.25 seconds
14 inches
0.27 seconds
16 inches
0.29 seconds
18 inches
0.31 seconds
My Reaction Time Data:
Trial Number
Distance caught (Inches)
Reaction Time (seconds)
1
2
3
4
5
6
7
8
9
10
My Tutor’s Reaction Time Data:
Trial Number
Distance caught (Inches)
Reaction Time (seconds)
1
2
3
4
5
6
7
8
9
10
Would you be able to see the baseball and swing the bat in time? With more practice
could you do it?