Energy

From Wikipedia, a free encyclopedia written in simple English for easy reading.

Energy is a word with more than one meaning.

• Energy broadly means the capacity of something, a person, an animal or a physical system to do work and produce change.
  • It can refer to the ability for someone to act or speak in a lively and vigorous way.
  • It is used in science to describe how much potential a physical system has to change.
  • It may also be used in economics to describe the part of the market where energy itself is harnessed and sold to consumers.

Contents 1 Energy in Science 2 Conservation of Energy 2.1 Example of Conservation of Energy 2.2 New Conservation of Energy Rule 3 Types of Energy 4 Measuring Energy 4.1 Some units of Measurement for Energy 5 See also

[edit] Energy in Science

Energy is something that can do work.

There are three basic forms of energy:

• Kinetic energy
• Potential energy
• Rest energy

[edit] Conservation of Energy

When energy changes from one form to another, the amount of energy stays the same. Energy cannot be made or destroyed. This rule is called the "conservation of energy law".

[edit] Example of Conservation of Energy

Here is an example:

1. the energy of a thing is measured to start with
2. the energy changes from potential energy to kinetic energy and back again
3. at the end the energy of the thing is measured again

The measurements of energy at the start and end will be the same.

[edit] New Conservation of Energy Rule

Scientists now know that matter can be made into energy through processes like nuclear fission and nuclear fusion. The law of conservation of energy has therefore been extended to become the Law of conservation of matter and energy.

[edit] Types of Energy

There are many types of energy. For example:

• Light energy
• Heat energy
• Internal energy
• Sound energy
• Chemical energy
• Nuclear energy
• Elastic energy
• Gravitational energy

[edit] Measuring Energy

Energy can be measured. That is, the amount of energy a thing has can be given a number.

As in other kinds of measurements, there are measurement units. The units of measurement for measuring energy are used to make the numbers meaningful.

[edit] Some units of Measurement for Energy

The SI unit for both energy and work is the joule (J). It is named after James Prescott Joule. 1 joule is equal to 1 newton-metre. In terms of SI base units, 1 J is equal to 1 kg m² s⁻².

The energy unit of measurement for electricity is the kilowatt-hour (kW·h). One kW·h is equivalent to 3,600,000 J (3600 kJ or 3.6 MJ).

[edit] See also

• Heat