We are exploring matter using measurements of mass and volume. Did you know that when two different liquids are mixed, the new volume can actually be less than the sum of the original volumes? 25 mL of water and 25 mL of rubbing alcohol only measured 48 mL when they were mixed together. The mass didn’t change because we didn’t lose any atoms or molecules. Mass is a measure of the amount of matter but volume is just the space that is taken up by matter.