Volume is the measurement of the amount of space that a liquid, solid or gas takes up in a container. Common measurements of volume include gallons, ounces and teaspoons.
While volume is a measurement of space a given amount of a substance takes up, mass is the measurement of how much of a substance there actually is. For instance, 1 gallon of water and 1 gallon of sulfuric acid have the same volume but not the same mass due to differences in their molecular structure. In physics, the more complex definition of mass is the amount of resistance a substance or object has to being moved and the level of gravitational attraction it has with other objects.