What Makes a Shadow Have a Fuzzy Edge?

Imagine you're shining a flashlight on a wall, and there's a small object blocking the light. The shadow it makes is usually sharp, like when you put your hand between the light and the wall. But sometimes, especially if the light is far away or not very bright, the edges of the shadow get soft and blurry, almost like they’re melting into the background. That happens because light behaves like waves, and those waves can bend around the object a little bit, kind of like how water spreads out when it goes over a rock in a stream.