This lab uses bromothymol blue solution, an indicator that turns green in acidic conditions, Elodea plant pieces, and test tubes to study photosynthesis and respiration. Carbon dioxide produced during respiration acidifies the solution and turns it green, while oxygen produced during photosynthesis in the presence of light makes the solution blue.

1. Lab – Photosynthesis & Respiration

2. Background Info Bromothymol blue is an indicator that changes when it is in the presence of certain substances. When exposed to an acid, it turns green. Carbon dioxide dissolved in water creates an acidic solution, therefore turning the solution green .

3. Elodea is an aquatic plant, native to North America and widely used as aquarium vegetation.

4. Materials: 3 test tubes 3 small pieces of parafilm 3 pieces of Elodea plant 1 straw Bromothymol solution