Mass is measured in kilograms (kg), grams (g), or milligrams (mg). The mass of an object does not change unless matter is added or removed.
Volume is measured in cubic meters (m^3), cubic centimeters (cm^3), or liters (L). The volume of an object can change if the object's shape changes or if the object is heated or cooled.
The density of an object is a measure of how much mass is packed into a given volume. Density is calculated by dividing the mass of an object by its volume. The density of an object is measured in kilograms per cubic meter (kg/m^3), grams per cubic centimeter (g/cm^3), or milligrams per liter (mg/L).
The following table shows the relationship between mass, volume, and density:
| Property | Symbol | Units |
|---|---|---|
| Mass | m | kilograms (kg), grams (g), milligrams (mg) |
| Volume | V | cubic meters (m^3), cubic centimeters (cm^3), liters (L) |
| Density | ρ | kilograms per cubic meter (kg/m^3), grams per cubic centimeter (g/cm^3), milligrams per liter (mg/L) |
Changes in Mass and Volume
The mass of an object can only change if matter is added or removed. The volume of an object can change if the object's shape changes or if the object is heated or cooled.
When an object is heated, its volume usually increases. This is because the heat energy causes the atoms and molecules in the object to move faster and farther apart.
When an object is cooled, its volume usually decreases. This is because the heat energy causes the atoms and molecules in the object to move slower and closer together.
The density of an object can change if the mass or volume of the object changes. If the mass of an object increases, its density will increase. If the volume of an object increases, its density will decrease.
