• The word energy comes from the Greek word energeia.
  
  
  
• Most types of energy are either a form of kinetic energy or potential energy.
  
  
  
• Common examples include heat energy, elastic potential energy, chemical energy, sound energy, nuclear energy, geothermal energy and gravitational potential energy.
  
  
  
• Kinetic energy refers to the energy an object has because of its movement. A car in motion has kinetic energy, as does a basketball when you pass or shoot it.
  
  
  
• Energy can be transformed from one form to another. In lightning, electric potential energy transforms into light, heat and sound energy.
  
  
  
• The law of conservation of energy states that energy can only be transformed, it can’t be created or destroyed.
  
  
  
• You might have heard of Albert Einstein’s famous formula E = mc² (energy equals mass multiplied by the speed of light squared).
  
  
  
• Food contains chemical energy which is used by living organisms such as animals to grow and reproduce. Food energy is usually measured in calories or joules.
  
  
  
• Wind farms contain large numbers of wind turbines which are used to transform wind energy into a useful energy such as electricity. The use of wind power to generate electricity doubled between the years 2005 and 2008. More wind energy facts.
  
  
  
• The USA's Mojave Desert is home to the world's largest solar power plant. More solar power facts.
  
  
  
• The Three Gorges Dam in China is the world's largest hydroelectric power station. More hydropower facts.
  
  
  
• Nuclear power produces around 13% of the world's electricity. More nuclear power facts.
  
  
  
• Plants use energy from sunlight during an important process called photosynthesis.
  
  
  
• A person standing on a diving board above a swimming pool has gravitational potential energy.
  
  
  
• During chemical reactions, chemical energy is often transformed into light or heat.
  
  
  
• Stretched rubber bands and compressed springs are examples of elastic potential energy.