Question: How does the density of objects change?

Steph Owen answered on 13 Jul 2020: last edited 13 Jul 2020 5:18 pm

So density is how much something weighs divided by the space it takes up.

An example is if you’re in a swimming pool and breathe in, you float! this is you becoming less dense! This happens because breathing in expands your lungs and you take up a bigger space. But your weight is the same as the air didn’t add anything to your weight. So your weight divided by your space, ie your density, goes down, to make you float more in water!

ways of making objects less dense generally would be to take stuff out of the middle so it weighs less for the same total space it takes up, sponges are not very dense for example because they have little air holes in, a solid wood block is more dense but the particles in wood are further apart and the particles weigh less than those in metal for example

objects also become less dense when they’re heated, this is cause the heat energy allows the molecules to spread out a little bit so the object takes up more space but weighs the same still = less dense