Used as a pH indicator in analytical chemistry, bromothymol blue is particularly effective for detecting weak acids and bases. It is commonly employed in laboratory settings to monitor pH changes in solutions, especially in the range of 6.0 to 7.6, where it transitions from yellow to blue. This makes it ideal for applications such as testing water quality, including aquarium and pond water, to assess acidity or alkalinity. It is also used in biology laboratories to demonstrate respiration and photosynthesis, as the color change visually indicates carbon dioxide levels in solution. In educational experiments, it helps students observe metabolic processes in living organisms like yeast or small aquatic animals. Additionally, it serves in some medical and environmental testing procedures where a clear, visible pH shift is needed.