This is a hands-on demonstration. Try this with your friends, and be prepared to explain the physics of the demonstration to them.
Work Step by Step
No light gets through the linear polarizers that are crossed at right angles. However, when the syrup is placed between the polarizers, light that goes through the first polarizer, and then the syrup, can pass through the second polarizer. Corn syrup is an "optically active" material, which means it can rotate the plane of polarization of light. The amount of rotation is color-dependent, so you will see a riot of colors.