Energy
n physics, energy is an indirectly observed quantity which comes in many forms, such as kinetic energy, potential energy, radiant energy, and many others; which are listed in this summary article. This is a major topic in science and technology and this article gives an overview of its major aspects, and provides links to the many specific articles about energy in its different forms and contexts.
The question "what is energy?" is difficult to answer in a simple, intuitive way, although energy can be rigorously defined in theoretical physics. In the words of Richard Feynman, "It is important to realize that in physics today, we have no knowledge what energy is. We do not have a picture that energy comes in little blobs of a definite amount.".[1]
However, it is clear that energy is always an indispensable prerequisite for performing work or causing changes, and the concept has great importance in natural science.
Contents [hide]
1 Forms of energy
2 History of understanding
3 Units of measure
4 Energy in various contexts
5 Energy transformation
6 Conservation of energy
7 Applications of the concept of energy
8 Energy transfer
9 Energy and the laws of motion
10 Energy and thermodynamics
11 Measurement
12 See also
13 Notes and references
14 Further reading
15 External links
Forms of energy
Main article: Forms of energy
Energy exists in many forms:
Heat, a form of energy, is partly potential energy and partly kinetic energy.
In the context of physical sciences, several forms of energy have been defined. These include:
Thermal energy, thermal energy in transit is called heat
Chemical energy
Electric energy
Radiant energy, the energy of electromagnetic radiation
Nuclear energy
Magnetic energy
Elastic energy
Sound energy
Mechanical energy
Luminous energy
Mass (E=mc²)
These forms of energy may be divided into two main groups; kinetic energy and potential energy. Other familiar types of energy are a varying mix of both potential and
The question "what is energy?" is difficult to answer in a simple, intuitive way, although energy can be rigorously defined in theoretical physics. In the words of Richard Feynman, "It is important to realize that in physics today, we have no knowledge what energy is. We do not have a picture that energy comes in little blobs of a definite amount.".[1]
However, it is clear that energy is always an indispensable prerequisite for performing work or causing changes, and the concept has great importance in natural science.
Contents [hide]
1 Forms of energy
2 History of understanding
3 Units of measure
4 Energy in various contexts
5 Energy transformation
6 Conservation of energy
7 Applications of the concept of energy
8 Energy transfer
9 Energy and the laws of motion
10 Energy and thermodynamics
11 Measurement
12 See also
13 Notes and references
14 Further reading
15 External links
Forms of energy
Main article: Forms of energy
Energy exists in many forms:
Heat, a form of energy, is partly potential energy and partly kinetic energy.
In the context of physical sciences, several forms of energy have been defined. These include:
Thermal energy, thermal energy in transit is called heat
Chemical energy
Electric energy
Radiant energy, the energy of electromagnetic radiation
Nuclear energy
Magnetic energy
Elastic energy
Sound energy
Mechanical energy
Luminous energy
Mass (E=mc²)
These forms of energy may be divided into two main groups; kinetic energy and potential energy. Other familiar types of energy are a varying mix of both potential and