Thermal energy is energy that comes from the motion of tiny particles of matter. The faster the particles move the warmer the matter can get. For example a cup of hot tea has thermal energy. If you mix a cup of hot tea with a cup of ice water some of the thermal energy from the hot tea is transferred into the particles of the ice water. The hot tea is cooler because it lost thermal energy to the ice water.

Most objects contain some thermal energy. Rub your the palms of your hands together and your hands will become warm. Adding thermal energy to an object makes the object's molecules move faster. When you add thermal energy to water, the water molecules move faster. The molecules can move so fast that some molecules begin to leave the container as the water boils and evaporates. Thermal energy can turn a solid into a liquid and a liquid into a gas. All objects have some thermal energy, except objects that are at absolute zero. This temperature is thought to be about −273.15∘C. At this temperature, scientists believe that all motion of particles stop and therefore, there is zero thermal energy.

Radiant energy is energy in the form of light and other electromagnetic waves. The energy from the sun is transmitted to Earth by electromagnetic waves. Visible light is one type of radiant energy that is part of the electromagnetic spectrum. Visible light is made up of a mixture of colors of light. The electromagnetic spectrum is the range of different kinds of energy that is transmitted by electromagnetic waves. The electromagnetic spectrum includes: radio waves, microwaves, infrared waves, visible light, ultraviolet waves, X rays, and gamma rays.

If you have ever had a sunburn, you have experienced the effect of too much radiant energy on your skin. You cannot see radiant energy, but you can certainly feel the results of the energy.