The Law of Conservation of Energy


Energy can change form, but it can’t be created or destroyed. This is the Law of Conservation of Energy. 


Let’s look at a kettle boiling. It takes one form of energy (electricity) and turns it into other forms of energy (thermal and sound) in the process of boiling water.


Or think about a car. The engine transforms the chemical energy in fuel into mechanical energy to make the car move.


Energy can appear in a number of different forms, including kinetic (movement), heat, sound, light, and potential (stored) energy.

A straightforward explanation of common units used to measure electricity.

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Primary vs. secondary sources

Primary sources of energy are found in nature. They include coal, natural gas, water, wind and biomass. The Sun is the original energy source for all of these things. 

There is one primary source of energy that doesn’t rely on the sun. It’s heat energy from the centre of the Earth, which rises up through hydrothermal vents in the sea bed/floor. Down there, giant tube worms and clams rely on this energy to survive.


Secondary sources of energy are produced from primary sources. An example of this is coal; which is a primary source. But when coal is used to make electricity, the electricity is a secondary source of energy.

Electricity can come from both renewable and non-renewable primary sources. In Australia, the main way we generate electricity is in power plants that burn coal, a non-renewable fossil fuel. 


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In just five years the number of Australian solar PV systems went from 8,000 to 1,000,000

Wrap up


The Law of Conservation of Energy states that energy cannot be created or destroyed.


When we use energy, we’re transforming it from one form to another. For example, a light bulb changes electrical energy into heat and light energy.


Primary sources of energy are found in nature, and most primary sources first got their energy from the sun. They can be renewable or non-renewable.


Secondary sources of energy are those that we have converted from primary sources, so we can use them in daily life. Electricity is a great example.