Obtaining and using energy

1. Forms of energy Energy is a property of matter which gives it the ability to produce change in its own physical and chemical properties and in those of other bodies... The main forms. [...]

Energy drives the Universe and is part of all the changes which take place on Earth. The Sun is our main source of energy. Without it, there would be no life and most other sources of energy would not exist. [...]

1.1. Energy Energy is a property of matter which gives it the ability to produce change in its own physical and chemical properties and in those of other bodies. 1.2. [...]

2.1. Forces do work A force does work on a body when it displaces it (figure 1). This is because it changes its energy. For example, if we apply a force to a moving object, the velocity of this object will change, as will its kinetic energy. [...]

Simple machines The most rudimentary machines are called simple machines. They are basic, but they are of great help in performing tasks and transferring energy. The Wheel A wheel is a circular object which turns on an axle. [...]

3.1. The need for energy through history In prehistoric times, human beings, who were nomadic hunter-gatherers, needed no other energy than fire to keep them warm and cook their food. [...]

4.1. Coal Coal is a solid, black rock. It is the fossilised remains of huge masses of vegetation buried under the ground millions of years ago (figure 1). [...]

5.1. Pollution of the environment The production, transport and use of nonrenewable sources of energy generates environmental pollution. [...]

The environmental costs of energy production Pollution of the environment due to the way we obtain and use energy produces adverse effects like the following. [...]

6.1. Water power Hydroelectric power stations obtain electrical energy from water power (figure 1). Water is a resource which does not run out: the water cycle constantly renews the water on our planet. 6.2. [...]

7.1. Sustainable energy consumption Three quarters of all the energy produced is consumed by only 15 % of the Earth's population. [...]

Ways to save energy Measures for saving energy are the responsibility of both individuals and society in general. This page shows you some of the ways to save energy. [...]

Energy drives the Universe and is part of all the changes which take place on Earth. The Sun is our main source of energy. Without it, there would be no life and most other sources of energy would not exist. [...]

Energy drives the Universe and is part of all the changes which take place on Earth. The Sun is our main source of energy. Without it, there would be no life and most other sources of energy would not exist. [...]

Energy drives the Universe and is part of all the changes which take place on Earth. The Sun is our main source of energy. Without it, there would be no life and most other sources of energy would not exist. [...]

Energy drives the Universe and is part of all the changes which take place on Earth. The Sun is our main source of energy. Without it, there would be no life and most other sources of energy would not exist. [...]