California Science Test (CAST) 8th Grade Practice Exam

Density is how much matter is packed into a given space, calculated as mass divided by volume. When something becomes more compact, its volume gets smaller but the amount of matter stays the same, so density increases. That’s exactly why making a substance more compact makes it denser.

Temperature can influence density because many materials expand when heated, increasing volume and lowering density, but density isn’t determined by temperature alone. Different materials have different densities, and color doesn’t affect density at all since density depends on mass per volume, not appearance.

So the idea that the more compact something is, the more dense it becomes is the correct way to describe the relationship.