A slit is a narrow opening or cut in a surface or material. Slits can be found in various contexts, such as in machinery, where they allow for the passage of light or air, or in textiles, where they can create design features. The width and length of a slit can vary depending on its purpose. In science, slits are often used in experiments, such as the famous double-slit experiment in quantum mechanics. This experiment demonstrates the wave-particle duality of light and particles, showing how they can behave like both waves and particles when passing through two closely spaced slits.