Science: Section 1


A fuel is a substance that burns to release energy.

When a fuel burns the chemical reaction is known as combustion. When combustion takes place the fuel is reacting with oxygen in the air to release energy in the form of heat and light.

There are various substances that can be used as fuels such as coal, oil, natural gas, ethanol, biomass and biogas. They are incredibly important substances in our modern world as they provide energy for transport, electricity, and heating for homes, but they do have a down side. When some fuels are burned they release pollutant gases and fine particles that can affect the quality of the air that we breathe. This is a big problem in areas such as town and cities where there are lots of vehicles that are burning these fuels.

Combustion Experiments

The following three videos demonstrate the combustion of some fuels

Click here to show the Whoosh Bottle Experiment Video

Click here to show the Methane Tin Experiment Video

Click here to show the Dynamite Soap Experiment Video

Fossil Fuels

Coal, oil and natural gas are known as the fossil fuels.  They are called the fossil fuels because they were formed by dead plants and animals kept under pressure for millions of years.



arrow Formed by dead plant material
Used by power plants to produce electricity for our homes


arrow Formed from dead sea creatures and plant material
Has many, many uses such as petrol, plastics, diesel, tar and lubricating oil.


arrow Formed alongside both coal and oil
Known as natural gas it is used to heat homes

All 3 fossil fuels are said to be finite, this means that they are running out and cannot be replaced. The table below shows approximately how long they may last.

Fossil Fuel Years Left
Coal 100
Oil 40
Gas 50

Governments across the world are planning to stop using fossil fuels altogether by the end of the century, switching to renewable sources.

Renewable Fuels

Biofuels are produced from plant material, and unlike fossil fuels, they are renewable meaning that they will not run out. Shown below are some examples of biofuels.

  • Ethanol – Ethanol (alcohol) is produced by fermenting sugar. It can be mixed with petrol to fuel cars. This is already done in Brazil!
  • Biogas – This is mainly methane. It's produced from rotting vegetable waste and animal manure (POO POWER!). It can be used to fuel cars and produce electricity in power stations.
  • Biomass – This is plant-based material which can be burned to release energy. Biomass can also be converted to other usable forms of fuel. These include methane gas, ethanol and biodiesel.

Hydrogen is another renewable fuel and is said to be the fuel of the future. It can be produced from water. Some cars can already run on hydrogen. It is an excellent fuel because all it produces when it burns is WATER!

There is also a Homework Sheet you can download that supports and develops further the ideas from this section.