1. Observation: When I exercise, I sweat, I breathe heavily, I get warmer,
my face turns red, my heart beats faster…hmmm?
Hypothesis: “What are the effects of exercise on metabolism?”
Prediction:
Gather Data:
Safety: 0.1 M NaOH is caustic. Avoid contact with skin. Use of
of goggles mandatory. Flush contacted skin with soap and
water. Bases feel “slippery”.
Avoid drinking bromothymol blue
Procedure: Pour 100 mL of bromothymol blue solution into a
clean Erlenmeyer flask. Make a data table and
record original color

2. Exhale breath through 3 drinking straws into bromo thymol blue solution for 1 minute. Record color. Titrate color of solution back to original color by adding drops of 0.1 M NaOH solution. Record the number of drops.
Dump out solution and rinse flask, then refill the flask with 100 mL of fresh bromothymol blue solution.
Exercise for 1 minute (either sit-ups or running). Without resting, immediately exhale breath through same drinking straws for 1 minute. Record color of solution. Titrate color of solution back to original color with drops of 0.1 M NaOH solution. Record number of drops.