Energy measures the ability to do work. Electromagnetic waves and mechanical waves are two ways that energy is transported. Mechanical waves are waves in water and sound waves that are caused by a vibration of solid, liquid, gas, or plasma. Medium is the term used to refer to waves that are traveling through matter. However, water waves are able to transfer energy without transferring matter. How this is done is by the wave's energy traveling through the water and leaving the water molecules in place.