What does photosynthesis have to do with the use of Bromothymol Blue?

Answer 1

Bromothymol blue is an indicator which changes colour in the presence of an acid. When carbon dioxide mixes with water it produces carbonic acid (soda water). A pretty common experiment involves putting a respiring organism in water mixed with bromothymol blue, the water should turn yellow as the organism takes in oxygen and produces carbon dioxide. The indicator can be changed back to its original blue colour by removing the carbon dioxide from the water, i.e. putting in a plant to run photosynthesis - drawing out the carbon dioxide to produce oxygen.

Answer 2

Bromothymol Blue is commonly used as an indicator to detect the presence of carbon dioxide in a solution. In the context of photosynthesis, Bromothymol Blue can be used to observe the rate of photosynthesis. When photosynthesis occurs, carbon dioxide is consumed and oxygen is released. By adding Bromothymol Blue to a solution containing a photosynthetic organism, the color change of the indicator can indicate the rate of photosynthesis.