A Simple Colorimeter for Measuring the Concentration of Multicomponent Food Coloring

Built-in instruments are commonly employed in physics experiments. In this case, students usually unaware of the instrument’s fundamental physics. Here we constructed a simple and compact colorimeter. A light-emitting diode (LED) was used as light source. The detector circuit consists photoresistor, resistor, 9-V battery. During experiment, illuminated solution food coloring. transmitted measured via voltage resistor to obtain absorbance. value then determine concentration solution. This instrument has been measure mixture coloring’s e.g. 1 ml/l Carmoisine Ponceau. For sample, measurement gave 0.97 0.81 is appropriate for teaching.