Source and Form of Energy

  • Energy is the ability to do work. There are renewable and non-renewable energy sources. These sources of energy are important for humans to carry out daily life. Energy cannot be created or destroyed; however can be transferred or altered from one form to another.
7.1  Source and Form of Energy
  • Energy is the ability to do work
  • Energy can be obtained from various sources such as:
  1. Sun
  2. Water
  3. Air
  4. Nuclear
  5. Waves
  6. Fossil fuels
  7. Biomass
  8. Geothermal
Energy sources Description


  • The sun is the main energy source.
  • Solar energy can be used to generate electricity through solar panels.


  • Flowing water rotates the turbine in the dam to generate electricity.


  • The blowing wind rotates the windmill to generate electricity.


  • Nuclear substances such as uranium are used to generate electricity at nuclear power stations.


  • Waves rotates turbines in the sea to generate electricity

Fossil fuels

  • Fossil fuels such as petroleum, natural gas and coal are burned to generate electricity.


  • Biomass is a substance from plants (firewood and plant waste) or animal faeces used to produce fuel and generate electricity.


  • Geothermal is a source of energy derived from the heat of hot rocks beneath the earth's surface to generate electricity.
Form of energy Description
Solar energy
  • Energy from the Sun.
  • Produces heat & light
  • Can generate electricity
Heat energy
  • Stored on objects that have heat
Light energy
  • Produced by objects that emit light
Sound energy
  • Produced by a vibrating object
Electrical energy
  • Flows in a complete electrical circuit
  • Enables electrical appliances to work
Chemical energy
  • Stored in substances such as food, fossil fuels, biomass or batteries
Kinetic energy
  • Present in moving object
Potential energy
  • Stored inobject that is at a certain height, that are stretched or compressed
Nuclear energy
  • Contained in nuclear substances such as uranium
Transformation of energy
  • Energy can be transformed from one form to another
  • Symbol -> means change to
  • Symbol + means and
  • While cycling, the chemical energy from the food eaten transform into kinetic energy (movements of the legs & bicycle).
  • Chemical energy -> Kinetic energy
  • When turning on the television, the electrical energy (in the electrical circuit of the television) transform into light energy (image) & sound energy.
  • Electrical energy -> Light energy + Sound energy
  • As the flame burns, the chemical energy stored in the fuel transform into heat energy and light energy.
  • Chemical energy -> Heat energy + Light energy
  • While diver jump from the diving board, the potential energy (high position of the jumper) transforms into kinetic energy (movement of the jumper) and then changes to sound energy (water splash sound)
  • Potential energy -> Kinetic energy -> Sound energy
  • When turning on a flashlight, the chemical energy stored in the battery transforms into electrical energy (in the electrical circuit of the flashlight). Then, electrical energy transforms into heat energy (bulb becomes hot) & light energy (bulb lights up).
  • Chemical energy -> Electrical energy -> Heat energy + Light energy
  • When using a solar calculator, the solar energy obtained from the Sun transforms into electrical energy (in the calculator circuit). Then, the electrical energy transforms into light energy (the screen emits light).
  • Solar energy -> Electrical eneergy -> Light energy
  • As the vehicle moves, the car engine transforms the chemical energy stored in fossil fuels into kinetic energy (car movement)
  • Chemical energy -> Kinetic energy
  • Plants make their own food. During photosynthesis, plants transforms light energy from the Sun into chemical energy stored as starch.
  • Solar energy -> Chemical energy
  • While playing a skateboard, players start from a high place then glide down. Upon reaching the end, the player will stop at the highest position for a moment and then resume his movement again.
  • Potential energy -> Kinetic energy -> Potential energy
Energy cannot be created or destroyed
  • All the changes that take place in this universe involve energy.
  • Energy cannot be created or destroyed, but can change form.