LabLearner—The Science of Learning
LabLearner—The Science of Learning

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Examining Exercise

Investigation 2 – Lab

 

 

 

 

 

 

 

Back to Investigation 2

BE PREPARED

Supplies and Equipment:

Group Materials:

  • 1 timer or stopwatch
  • 1 50 ml beaker
  • 1 100 ml beaker
  • 1-liter pitcher
  • 1-liter graduated cylinder
  • 3 pieces of tape (10 cm in length)
  • water

Pair Materials:

  • 1 stethoscope
  • 2 alcohol swabs
  • 1 timer or stopwatch
  • 1 calculator

Individual Materials:

  • 1 Student Data Record

Teacher Preparation:

1. For Trials 4 and 5, cut three (3) pieces of tape for each group.

2. For Trials 1 through 3, separate the class into pairs.

3. For Trials 4 and 5, combine pairs into groups of four.

Instruction:

1. Direct each student pair to obtain the following necessary materials from the distribution point: one (1) stethoscope, one (1) timer or stopwatch, and two (2) alcohol swabs.

GET FOCUSED

Investigation Two students assess the impact of exercise on pulse and heart rate.

 

INVESTIGATE

1. Trials 1 – 3: Students will explore the immediate effects of exercise on the cardiovascular and respiratory systems during this part of the Investigation. Any student with a medical condition may act as the timekeeper for the class.

One student in each pair will act as the “athlete” and the other student will act as the “physician.” Three Trials will be conducted in which the heart rate and respiratory rate of the athlete will be recorded during a 30-second interval. During the timed 30-second interval, the physician should obtain the heart rate, and the athlete should count his/her breaths to obtain the respiratory rate.

  • In Trial 1, the athlete will sit for two minutes before the rates are obtained. During this time period, the physician should practice finding the athlete’s heartbeat by placing the flat end, or diaphragm, of the stethoscope on the chest, just over the heart.
  • In Trial 2, the athlete will stand while the rates are obtained.
  • During Trial 3, the rates will be obtained after the athlete jogs in place for a one-minute interval. If time permits, students can switch roles.

The experiment is designed so that students understand that as the oxygen and nutrient demand of the muscles increases, heart rate and respiratory rate increase in order to meet the demand. The students will answer a question that is the main focus of the experiment and predict their resting heart rates before obtaining the information.

How does exercise affect your cardiovascular and respiratory systems?

 

 

2. Trials 4 – 5: During the second part of the Investigation, the student pairs should join with another pair to form groups of four. They should obtain the following additional materials from the distribution point: one (1) 50 ml beaker, one (1) 100 ml beaker, one (1) liter pitcher, one (1) liter graduated cylinder, and three (3) 10 cm pieces of tape.

Students will conduct two Trials using models to represent the activity of a “strong” heart and a “normal” heart.

In Trial 4, they will use the “normal heart” to pump blood to muscles. Within the context of the model, this will be accomplished as they determine the time required to transfer 1000 ml of water from a liter pitcher into a liter graduated cylinder using a 50 ml beaker.

In Trial 5, students will use the “strong heart” to pump blood to muscles. The strong heart is that of someone who regularly participates in cardiovascular exercise. In this Trial, students will use a 100 ml beaker to transfer 1000 ml of water from the liter pitcher to the liter graduated cylinder, and again measure the time needed to complete the task.

These two Trials have been designed to illustrate the effect of regular cardiovascular exercise or training on the heart and the differences in how each heart delivers blood during exercise.

Cardiovascular training increases the size of the left ventricle chamber, such that it is capable of holding and pumping a greater volume of blood as compared to someone who does not participate in a regular cardiovascular exercise program. This is considered a long-term benefit as it does not happen immediately after one or two periods of cardiovascular exercise, but after regular training (several weeks). The benefit of the increased size of the left ventricle is two-fold. During periods of rest, a person with a “strong” heart will have a lower resting heart rate because the heart can pump more blood with each beat. Therefore, the “strong” heart will need to pump less frequently to deliver the same volume of blood as the heart of someone who does not exercise regularly. During exercise, the person with the “strong” heart will be able to pump more blood per minute that the person with the normal heart for the same increase in heart rate.

Students will compare and analyze the results to answer a question that is the main focus of the experiment.

What is the long-term effect of cardiovascular training on the heart?

KEYS

CLEAN UP

Let students know your expectations for clean-up. Ask them to clean up.