BTB- bromthymol blue solution (indicator) solution (indicator)  Used to detect the presence of carbon dioxide  Used to detect the presence of carbon dioxide Turns YELLOW if CO 2 is present

A: Measure CO2 exhaled at rest B: Measure CO2 exhaled after exercise Measure time for BTB to change from blue to yellow Measure no. of drops needed to change BTB back Practice breathing out to maintain constant exhalation Control accuracy of size of drops exercise Rate of change in BTB 1.Same person exhaling 2.Constant breathing 3.Time of exhalation

EXPERIMENT Will exercise affect the rate of change in BTB solution? Control Student at Rest Experimental/Test Group) Student Exercising Independent variable (tested/changed) Dependent variable (measured/result) FAIR TEST (AVOID errors) same person tested constant breathing same breathing time COLLECT DATA

If exercise is done then, the rate of change of BTB will be (faster/slower) because (more/less) carbon dioxide is produced during exercise. When a person exercises, (explain your understanding of breathing and respiration).

Blow air for 1 min (CO 2 ) BTB solution Changes to YELLOW if CO 2 Changes to YELLOW if CO 2 is detected Record the time the solution changes color. PART A. At Rest (three trials) Add drops of Ammonia (base) until solution is neutralized (changes back to blue) CO 2 + Water forms an acid

Blow air for 1 min (CO 2 ) BTB solution Changes to YELLOW if CO 2 Changes to YELLOW if CO 2 is detected Record the time the solution changes color. PART B. After exercise (three trials) Add drops of Ammonia (base) until solution is neutralized (changes back to blue) Exercise for 1 min

Ammonia Acid Base Neutral X no of drops of ammonia needed to neutralize Acid in BTB solution