World Energy Needs

World Energy Needs

Acid Rain

• When fuels are burnt, sulfur combines with oxygen and forms sulpher di oxide----reacts with oxygen and water vapors --> sulphuric acid--falls down as acid rain

• Effects: -

• - removes minerals from the soil

• - causes acidity of water to increase in rivers and lakes

Energy Review

What are the kinds of energy we have learnt in previous grades?

What we use energy for

- In our homes, schools, factories and offices, we use energy for heating and cooling, for cooking, for lighting and so on.

- We need energy to travel around, so we use energy for transport.

- Industry uses energy for making things. Everyone uses things that are manufactured.

Open Ended

Can you name the fossil fuels in this pie chart?

Open Ended

What was the first fuel that humans used?

Wood

Fossil fuels

• You can see that most of the energy we use comes from fossil fuels

• . These are coal, oil and natural gas.

Chemical stores

• Fossil fuels are stores of chemical energy.

• The energy is released when the fuel is burnt.

• Fossil fuels are useful because they are very concentrated stores of energy. It takes only a minute or two for a driver to put 50 litres of petrol into the car’s tank. Then it is ready to travel 1000 km or more.

Open Ended

What name is given to the energy of a moving car?

Kinetic energy

Where energy came from

Fossil fuels are found underground. Coal formed from the remains of plants that died millions of years ago. Oil and gas formed from the remains of sea creatures.

Extracting oil and gas

In some parts of the world, oil and gas are extracted from under the seabed.

Generating electricity

• Electricity is a convenient way of sending energy from place to place. Most electricity is generated in power stations which burn fossil fuels, especially coal and gas.

Problems with fossil fuels

• Fossil fuels are non-renewable.

• Burning fossil fuels release carbon dioxide which contributes to climate change.

• Burning coal can release sulfur dioxide gas leading to acid rain.