* Density is a measure of how much mass is packed into a given volume. It's calculated by dividing the mass of an object by its volume: Density = Mass / Volume
* Weight is the force of gravity acting on an object's mass. It depends on both the object's mass and the gravitational field it's in.
Here's an example:
Imagine a large, fluffy pillow. It has a lot of mass (making it heavy) but it also has a large volume because of the air trapped within it. This means its density is relatively low.
Here are some other examples:
* A large ship: Ships are heavy because they are made of steel, but they are designed to have a large volume to displace water and float. This means they have a relatively low density.
* A feather: Feathers are lightweight but have a large volume, making them less dense than, for example, a piece of metal.
In summary:
* Heavy objects have a large mass.
* Dense objects have a large mass packed into a small volume.
It's possible for an object to be heavy (large mass) but not very dense (large volume).
