Density

Density explained in an easy to understand way:

Imagine trying to pack a suitcase for a week-long vacation, but it just won't close because it's too full. This is similar to the concept of density, where you're essentially trying to fit a certain 'mass' of clothes within the limited 'volume' of your suitcase. Just like how the suitcase's capacity is determined by how much you can pack inside it without exceeding its physical limits, an object's density is determined by how much mass it contains within a given space.