: Think of it as how "tightly packed" the matter is. For example, a cubic centimeter of bricks is much denser (1.6 g/cm³) than a cubic centimeter of feathers (0.0025 g/cm³). Key Characteristics
“The simple answer is how heavy something is for its size. If something seems very heavy for its size, we say it is more dense.” Purdue University density
: Since density is unique to each substance at a given temperature, it is often used to identify unknown materials. : Think of it as how "tightly packed" the matter is