Energy chains

Below are some examples of how energy can change from one form to another. These are called energy chains.

When a kettle is boiled, electrical energy is converted to heat energy.

When a mass is dropped from a height gravitational potential energy is converted to kinetic energy as the mass falls and then to sound and heat as it hits the ground.

Energy changes occur in chemical processes, such as the burning of coal, as well as biological and physical ones. The energy changes involved in the burning of coal are:

Energy changes also play a vital role in biological processes. When sunlight falls on green plants, it provides energy which causes a chemical reaction. Carbon dioxide and water combine to form biomass/carbohydrate and oxygen. This process is called photosynthesis. The energy (originally provided by the Sun) can later be released in living cells during the process called respiration. Alternatively it can be released when the biomass is burnt. In each of these cases the biomass and oxygen recombine to produce carbon dioxide and water again and release energy.


The Law of Conservation of Energy, Fuels, Fossil fuels
Generation of Electricity
Examples of renewable resources
Energy and force
Energy reference material, Self assessment questions