As you can see, energy can take various forms; energy has many ways of expressing itself. Heating your home using an electric heater requires many steps that involve the conversion of energy from one of these forms to another. Now you will learn how scientists describe the many faces of energy.

What Do We Know?

First of all, energy that enters the Earth from the Sun is referred to as radiant energy, the energy possessed by any type of electromagnetic radiation. Through photosynthesis, plants convert radiant energy to potential energy stored in the bonds of chemical compounds. The plants die and, over the course of millions of years, are converted into fossil fuels, which also possess potential energy in the chemical bonds of the fossil fuel molecules. Potential energy refers to the energy of an object due its position relative to other objects; the potential energy of molecules is a result of the positions of atoms relative to each other. In chemistry, we are especially concerned with the difference between the potential energy stored by the reactant and product molecules in a chemical reaction. For instance, molecules of coal and oxygen contain a great deal more potential energy than carbon dioxide and water vapor molecules, so that the combustion of coal to yield carbon dioxide and water releases a greater amount of energy. This is why coal is often combusted in power plants to boil water.

When coal is combusted in order to heat up water, the potential energy difference between the reactant and product molecules is converted into the thermal energy of the water in the boiler. The thermal energy of the water molecules, in turn, refers to the total kinetic energy of all the water molecules contained inside the boiler. Kinetic energy is energy due to an object’s motion. The motion of the object can be translational, rotational or vibrational. Since atoms, ions and molecules are constantly moving, these tiny, unseen particles possess kinetic energy.