All other colors of incident radiant energy are absorbed by the object. As an object absorbs energy, its temperature increases as a function of time. Students design their own experiments to investigate the rate that the water temperature inside the container changes with time for containers of various colors exposed to direct sunlight. Regular soda pop cans of various colors. Based on the results of their first experiment, the students predict the relative heating rates of the water in the soda pop cans of various different colors, then test their predictions by doing an experiment.
Temperature is a measure of the kinetic energy of the water molecules.
The increase in the kinetic energies of the water molecules causes an increase in the temperature of the water. The students monitor this temperature increase as a function of time using the CBL temperature probes. The order of the colors in a rainbow also makes for another interesting comparison. Recall that blue light carries the most energy, yellow less, and red light carries the least amount of radiant energy. If an object were a perfect absorber , it would absorb all the incoming radiant energy and reflect none, so the object would look completely black to our eyes.