Definition of Volume

• Volume is how much physical space a three-dimensional object takes up. Volume is typically quantified in units and sub-units such as cubic liters for liquids and gases, and cubic meters for solids.
  
  

Definition of Density

• Density is the amount of mass per unit of volume. That is, how much mass a three-dimensional object has within the physical space it takes up.
  For objects with a uniform, identical composition, the formula for density is "mass divided by volume equals density."
  
  

Similarities

• Volume and density are both used for measuring three-dimensional objects.
  
  

DIfferences

• Volume is used to determine the amount of physical space an object takes up, and density is used to determine how much matter is inside that physical space.
  Elements and substances have different masses, so even though two objects may have the same volume, their density may differ depending on the substance they are composed of.
  
  

Example

• A trash bag is filled with water. The amount of space that the bag takes up is the volume. The amount of matter inside the bag is the density. If the bag were filled with helium and tied, the amount of density inside the bag would change, because helium contains less mass than water.