UNIT 4 NATURAL: SOURCE OF ENERGY

Energy can be renewable or non-renewable.

Renewable energy is energy obtained from sources that are unlimited.

Hydroelectric energy: We get hydroelectric energy from water that is moving or falling. The water is collected in a reservoir. Then it passes through a turbine that generates electricity.

Wind energy: We get wind energy from the movement of air. The kinetic energy of the wind turns a turbine, and produces electrical energy.

Solar energy: We get solar energy from the Sun in the form of light and heat. Solar panels transform that energy into electrical energy.

Biofuels: We get biofuels from plant and animal products. Biofuels can be solid (biomass), liquid (bioliquids) or gas (biogases). Biofuels are burned in power stations to produce electrical energy or heat.

Non-renewable energy sources energy from sources that are limited.

Uranium: This radioactive metal is used in nuclear power stations to produce heat in nuclear reactions. Electricity is produced from this heat.

Natural gas Natural gas is a mixture of gases that have formed from decayed living things. It’s found underground. Natural gas is used as a fuel in many industries and to produce electricity. It’s used in homes for heating and cooking.

Coal is formed underground from decayed plants. Coal is used as fuel and to produce electricity in coal-burning power stations.

Petroleum This black liquid forms from decayed plants and animals. It’s the source of fuel that we use for heating and running vehicles and to produce electricity in oil-burning power stations.

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UNIT 4 ENERGY TRANSFORMATION

Energy never disappears. It can be transformed from one type of energy into another, but it doesn’t disappear completely.

Chemical energy: Vehicles transform the chemical energy in fuel and petrol into mechanical and thermal energy by the engine. We also transform chemical energy from the food into heat and movement.

Electrical energy: Machines transform electrical energy into kinetic and thermal energy. 

Light energy: Solar panels transform light energy from the Sun into electrical energy. 

The energy in food: The chemical energy stored in food and drink is measured in calories. The more calories in food, the more energy it contains. 

UNIT 4 ENERGY FORMS OF ENERGY

-Chemical energy is stored in some substances and can be stored in batteries.

-Thermal energy is related to the movement of atoms in an object or substance. Heat and temperature increase with an increase of these movements.

-Electrical energy is the movement of charged particles between two different places. Electricity travels to homes and factories through metal cables. 

-Nuclear energy is stored in the atomic structure of all matter. Scientists release this energy by breaking down radioactive materials, such as uranium.

-Sound energy: Sounds are made by vibrations travelling through the air, a liquid or a solid object.

-Radiant energy is energy in the form of electromagnetic waves. Light is an example of radiant energy.

-Mechanical energy produces movement. It’s the energy that enables people and things to move, go faster or change direction. There are two types of mechanical energy: kinetic energy and potential energy. Kinetic energy results from the motion of an object. Potential energy is the energy that results from the position of an object.