N-slit interferometer

An n-slit interferometer is a tool that scientists use to measure the size and shape of tiny things that you can't see with your eyes. It works like this: A bright light shines through a set of n (for example 3) slits or narrow openings. Then, the light that passes through the slits spread out in a pattern of light and dark areas so that it looks a bit like an upside-down smiley face. Scientists can look at this pattern to measure the size and shape of very small things.