Aerobic respiration is much more efficient than fermentation, but needs Oxygen, as CO₂ (and H₂O) is released in the citric acid cycle.

A. THE EFFECTS OF TEMPERATURE ON THE RATE OF FERMENTATION

1. Alcohol fermentation: C₆H1₂O₆ -> 2CH₃CH₂OH + 2CO₂ + energy; CO₂ is released as pyruvate is converted to acetaldehyde.
2. Yeast fermentation of sucrose at 4 different temperatures for 60 minutes.
3. Measure amount of CO₂ released in fermentation tube.

C. EFFECTS OF ACTIVITY ON HUMAN RESPIRATION RATES IN HUMANS

Cellular respiration releases CO₂ as one of its products, together with heat.

Carbon dioxide forms carbonic acid in water: CO₂ + H₂O -> H₂CO₃: this will be measured.

Use Phenolphthalein as pH indicator: colorless in acid, pink in neutral or basic (alkaline) solutions.

Use 0.5% NaOH to make 100 ml. standard solution with a light - medium pink color. Divide this 100 ml. into 2 flasks - one will be your standard, and the other will be the experimental flask.