CeipToursScience6: UNIT 7 NATURAL SCIENCE: ENERGY

WHAT IS ENERGY?

Energy is the ability to do work or cause changes. It is present everywhere and in everything.

Energy causes the changes we see around us. For example, energy makes a ball at rest move when it is kicked.

Energy can exist in many forms. Chemical energy, light energy, nuclear energy, mechanical energy, thermal energy and electrical energy are different forms of energy. The energy we use on a daily basis is obtained from different energy sources.

FORMS OF ENERGY

TYPES OF ENERGY --> INTERACTIVE ACTIVITY

PROPERTIES OF ENERGY

Energy can be transformed from one form to another. For example, chemical energy from fuel is transformed into mechanical energy in cars.
Energy can be transferred from one body to another. For example, when we hit a ball with a racket, most of the mechanical energy in the racket is transferred to the ball.
Energy can be stored. For example, batteries store chemical energy.
Energy can be transported from one place to another. For example, electrical energy is transported through electric cables.

ENERGY SOURCES

Energy sources are the natural resources from which energy is obtained. There are two types:

Renewable energy sources: are energy sources that are continuously replenished and will never run out. We can find different types:

The Sun emits energy as light and heat. Solar panels in solar power plants trap this energy and transform it into electrical energy.
Wind has mechanical energy and can move objects. When in motion, wind turbines in wind power plants transform mechanical energy into electrical energy.
Flowing water has mechanical energy, known as hydraulic energy. Hydroelectric power plants transform mechanical energy into electrical energy.
The Earth’s internal heat is thermal energy, known as geothermal energy. It can be transformed into electrical energy in geothermal power plants.
Biomass is biological material from plants and animals, such as wood, hay or cattle manure. Biomass has chemical energy which can be transformed into electrical or thermal energy. It can also be made into fuel for vehicles, known as biofuel.

Non-renewable energy sources are consumed faster than they can be replenished. They will run out one day. There are two main types of non-renewable energy sources:

Fossil fuels include coal, petroleum and natural gas. These fuels have chemical energy, which is transformed into electrical energy in thermal power plants. Fossil fuels can also be transformed into thermal energy to heat water and buildings. Petroleum products can be used as fuel for vehicles
Nuclear fuels include uranium and plutonium. These are elements that are found in some minerals. They release nuclear energy when their atoms are split apart or joined together. Nuclear power plants transform nuclear energy into electrical energy.

ENERGY AND ENVIRONMENTAL PROBLEMS

Energy provides us with modern comfort. However, energy use has some negative consequences:

Fossil fuels are limited resources.
Nuclear power plants produce radioactive waste, which is toxic to living things.
Burning fossil fuels releases toxic substances, causing air pollution. These substances can produce acid rain, which is harmful to plants and aquatic animals.
Burning fossil fuels also causes global warming.
The Sun emits light and heat. Some of this solar energy is reflected back into space; some reaches the Earth and warms its surface. The Earth’s surface emits heat back into space, but some of the heat is absorbed by gases in the atmosphere. These gases are called greenhouse gases, and include carbon dioxide and methane. This natural phenomenon is called the greenhouse effect. It is essential to make Earth warm enough for life. However, human activity is increasing the amount of greenhouse gases in the atmosphere. More heat is trapped in the atmosphere, so the Earth gets warmer.