Gelatin Lenses

Abstract We describe a low-cost and playful apparatus for geometrical optics experiments that uses everyday materials. The experimental setup is simple and easy to manipulate, and it entails making spherical lenses with Jell-O. Using paper templates, created in the desired shape, we cut the Jell-O in the format of a spherical lens. Using these materials, we measured the refraction index of the lenses using Snell's Law and measured the focal distance of a convergent Jell-O lens. Using a Jell-O lens, we simulated how the crystalline lens in the human eye works. By stretching and compressing the Jell-O lens, it is possible to observe a change in the focal position, illustrating the mechanism of accommodation that occurs in the human eye.