This is a, largely print in place Double slit experiment.

The double slit experiment, first performed by Thomas Young in 1801, demonstrates the wave-particle duality of light and matter. In this experiment, light (or particles like electrons) is directed towards a barrier with two closely spaced slits. Instead of forming two distinct bands on a screen behind the barrier (as particles would if they traveled through one slit or the other), an interference pattern of alternating bright and dark bands emerges, indicating that the particles behave like waves, passing through both slits and interfering with themselves.

However, when detectors are placed at the slits to observe which slit the particles pass through, the interference pattern disappears, and the particles behave like classical objects. This suggests that the act of measurement influences the system, highlighting the strange and counterintuitive nature of quantum mechanics.

I made this so any one, and any school with access to a 3d printer can make this to teach their students in a fun and engaging way.

All you need to complete this is a laser light and a piece of paper you cut 2 slits in with either a razor blade or scalpel.