Our universe is made up of energy and matter. Energy is the ability to do work - to make matter move or change. Forms of energy include chemical or thermal potential (stored) energy, mechanical (elastic) potential energy, and gravitational potential energy.  The kinetic energy (motion energy) of an object is related to its mass and speed. Graphics, diagrams and video explain how energy is measured (joules, calories, and kilowatt hours), the Law of Conservation of Energy, collision, the movement of electrons, conductors, insulators, radiant energy, thermal energy, and energy transfer (heat, light, motion). Multiple-choice reviews at the end of each segment reinforce important concepts.