How to make a fructose kaleidoscope
Warning! Only under adult supervision.
- 200 g fructose;
- 50 mL hot water;
- heat resistant jug;
- coffee filter;
- 2 polarizing filters.
Dissolve 200 g of fructose in 50 mL of hot water in a heat-resistant jug. If the fructose doesn't dissolve readily, heat the solution in a water bath. Pour the resulting viscous solution into a glass. Take a flashlight and trim a paper coffee filter to fit just inside its glass cover – this will serve to diffuse the light it emits. Arrange the objects in the following sequence: flashlight, polarizing filter, fructose solution, polarizing filter. Just turn the flashlight on and watch the colors in the glass swirl and change as you rotate the filter closest to you!
In addition to color and intensity, light has a property invisible to the naked eye known as polarization. Polarization determines the orientation of the vibrations of waves such as light. Sunlight or light from a light bulb is said to be “unpolarized” – its waves are polarized randomly in all orientations. A polarizing filter selects for just one direction of polarization. Two polarizing filters working in tandem will let through different amounts of light depending on how they are positioned relative to each other. The fructose solution affects the direction of polarization of the light passing through it – and it even changes the polarizations of different colors of light differently. Thus, the light is polarized by the first filter, enters the fructose solution, changes its polarization at different rates depending on color, and then hits the second filter, which only lets through colors with a suitable polarization. The scattered rays of light travel different distances, creating cool colored patterns!
Cool experiments await you in the MEL Physics subscription!