Name: _________________
Date:___________ Block: _______
Lab Partner: ______________________
How does exercise affect disposal of wastes from
cellular respiration?
Materials:
2 small test tubes
Glass-marking pencil
10-ml graduated cylinder
BTB solution
2 straws
timer
Pre-Lab:
1. What color change occurs to BTB solution after it mixes with Carbon Dioxide?
2.
3.
Predict how exercise will affect your body’s production of carbon dioxide.
Write a hypothesis for how each form of exercise that will affect your body’s rate
of CO2 production?
Procedure:
1. Decide on two different exercise and record them above your data table.
2. Label 2 test tubes A and B. Put 10 ml of water and a few drops (approx 3-4) of
BTB solution in each test tube. Carbon dioxide causes BTB to turn yellow or
green.
3. Your partner will time you during this step. When your partner says “go”, slowly
blow air through a straw into the bottom of a test tube A.
CAUTION: Do not inhale. When the solution changes color, your partner
should say ‘stop’ and then record how long the color took to change in the table
provided.
4. Replenish the BTB solutions according to step 2. Have partner #1 complete
exercise #1 for 1 minute, and then repeat step 3.
CAUTION: Do not exercise if you have a medical condition that interferes with exercise. If you feel
faint or dizzy, stop immediately, sit down, and notify instructor.
5. Continue alternating partners until both partners have completed both exercises
and all of the data has been recorded (trial 2). Then, try each exercise again
(trial 3). Your test tubes should be replenished after each trial.
6. Find the average time it took to change the BTB solution color. Record this
number in your data table.
Data:
Exercise #1: ______________________________________________________
Exercise #2: ______________________________________________________
Name of
Participant
Exercise
#
Time: Trial 1
(Rest)
Time: Trial 2
(After Exercise)
Time: Trial 3
(After Exercise)
Average Time
(After Exercise)
1
1
2
2
Analyze and Conclude
1.
2.
How did exercise affect the time for the solution to change color?
What process in your body produces CO2?
3. How/why does exercise affect the process described in number 2?
4. Was your prediction correct? Why or Why not?