ELI5: Explain Like I'm 5

what is the significance of the double slit experiment

The double slit experiment is an experiment that helps us understand how light and matter behave. The experiment works by shining a light through two slits. Then, the light passes through something that 'measures' the light, like a screen or detector. When this happens, something special happens: instead of the light being spread out evenly from both of the slits, there is an interference pattern- places where the light is very bright and places where there is no light at all. This pattern is called interference. The double slit experiment shows us that light behaves like a wave, and that it can interfere with itself. It also helps us understand how matter, like tiny particles, can show wave-like behavior too.