Mass and density are two commonly used physical properties of objects in physics that are very similar and share a close mathematical relationship. Mass and density should not be confused with weight.
Mass is a measure of how much matter there is within an object, typically given in grams. Mass is not affected by gravity, so a given object would have the same mass on Earth as in outer space.
Density is the amount of mass in an object per a certain amount of volume. Water has a density of 1 gram per cubic centimeter.
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The mathematical relationship between mass and density is often given by the formula: Density=Mass/Volume. This can be rewritten Mass=Density x Volume.
Weight is the force of the gravity that acts upon an object's mass. In the absence of gravity, objects have no weight.
Matter can come in liquid, solid or gaseous forms. Matter state often has a large impact on density, as gases tend to be far less dense than liquids or solids.