What they look like

The Colorimeter is used for Beer′s law experiments, determining the concentration of unknown solutions, or studying changes in concentration vs. time.

How the sensor works

Light from an LED passes through a cuvette containing a solution sample. Some of the incoming light is absorbed by the solution. As a result, light of a lower intensity strikes a photodiode. The amount of light that passes through the solution is known as transmittance. Transmittance can be expressed as the ratio of the intensity of the transmitted light, It, and the initial intensity of the light beam, Io, as expressed by the formula:

The Colorimeter produces an output voltage which varies in a linear way with transmittance.

Where it can be used

• Study absorbance vs. concentration e.g. chloroplasts
• Determine the concentration of an unknown solution (Beer′s Law experiments)
• Estimation of chlorine in water
• Digestion of starch by amylase
• Growth of yeast in a sugar solution