What is dense?

Dense means something is packed full of stuff, like a super tight hug from all directions.

Imagine you have two boxes, one is filled with soft feathers, and the other is filled with tiny pebbles. If you try to push your hand into the feather box, it feels easy, like pushing into a pillow. But if you push your hand into the pebble box, it feels harder, like trying to squish through a bunch of little rocks.

That’s what density means, how much stuff is packed into a space. If something has high density, it's heavy for its size, just like that pebble box.

• Big things can be dense too! A rock feels heavy because it's made of tightly packed particles.
• Small things can be less dense. Like how a balloon floats, the air inside is less dense than the air around it.

So, density is just a way to describe how "packed" something is, like how full your backpack feels when you stuff it with books instead of toys!