For us to do work, we need energy. Energy is measured in joules, (J) or kilojoules (kJ) Energy exists in many different forums such as Kinetic and potential energy – Kinetic energy is the movement of energy and potential is stored energy, energy ready to go. A lawn mower filled with gasoline, a car on top of a hill, and students waiting to go home from school are all examples of potential energy. Gravitational potential energy is the energy crazed by a body because of its elevation relative to a lower elevation, that is, the energy that could be obtained by letting it fall to a lower elevation. For example, water at the top of a waterfall or stored behind a dam at a hydroelectric plant has gravitational potential energy. Kinetic energy is energy at work. A lawn mower cutting grass, a car racing down a hill, and students running home from school are examples of kinetic energy. So is the light energy produced by lamps. Even electrical energy is kinetic energy.
Whenever we use energy to do work, it is in the kinetic state. Chemical energy is energy stored within the bonds between molecules. The most common examples of chemical energy are fuels such as gasoline, coal, and natural gas. Thermal energy is what comes from heat. For example, a cup of hot tea has thermal energy in the form of kinetic energy from it’s’ particles. When you pour some milk into your tea, some of this energy is transferred to the particles in cold milk. The cup of tea is cooler because it lost thermal energy to the milk. Electrical energy is whenever a current flows. A battery transfers stored chemical energy as charged particles called electrons, typically moving through a wire. For example, electrical energy is transferred to the surroundings by the lamp as light energy and thermal energy.
These forms of energy can be transferred and transformed between one another and exists in different forms. Example energy is stored as chemical energy in food, batteries and fuels which can be converted into sound, light and heat. Fossil fuels hold chemical energy; they give off light and heat energy when they burn. The heat energy is used to heat water, the water turns into steam which has kinetic energy. The turbine is moved by the steam which is kinetic mechanical energy. The generator is powered by the movement of the turbine which produces electrical energy.
A nuclear power station uses nuclear energy in the form of uranium as its main energy source. This undergoes nuclear fission that generates the thermal energy needed to heat water in a manner similar to a usual power station. We need energy to keep our bodies warm and to do work. This energy comes from the food we eat which is transferred in our bodies through a metabolism process; chemical reactions break down complex molecules to release energy and to use energy to build up other complex molecules.