Use a radiometer to show that light energy can be converted to mechanical energy.
The vanes, or wings, in the Radiometer are alternately dark and light in color. When the light strikes these wings it transfers heat to each one - but not at the same degree. The lighter wing reflects the rays and the darker wing absorbs the rays. The stronger the light, the more energy there is to heat up the darker side of the wing causing the wings to spin faster as the light gets brighter.
For light related science projects this radiometer may be used to indicate light energy or light intensity.