In this video by monkeysee, Emerald Robinson explains Liquids. Liquids are the rarest form of matter existing in the universe; this is because liquids can exist only within a narrow range of temperature and pressure. They have definite volume but no definite shape. Liquids have definite volume so they can not expand. They are called the condensed state of matter because they can not be compressed. Liquids can easily flow from one point to another under the action of gravity; thus they are called fluids. Generally, liquids have melting points at or below room temperature and boiling points above room temperature.