Angle of repose

Hey kiddo, have you ever played with sand, and tried to make a pile out of it? You might have noticed that the sand piles up to a certain angle, and if you tried to put more sand on top, it would just slide down. That's called the angle of repose.

The angle of repose is the steepest angle that a pile of material, like sand or dirt, can be piled up before it starts to slide down on its own. It's kind of like a limit that the material can handle before it becomes unstable and starts to slip away.

This angle depends on a few things, like the type of material, the size and shape of the particles, and how tightly packed they are. For example, sand has a lower angle of repose than rocks because sand particles are smaller and rounder, making them more likely to slide around.

So, next time you play in the sand, try making different piles at different angles and see if you can find the angle of repose. Remember, it's the steepest angle the pile can handle without sliding down!