ENERGY
Scientists define
EXAMPLE
ability to do work
People use energy to walk and bicycle
There are many different forms of energy, including
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Heat
Light
Motion
Electrical
Chemical
Gravitational
Forms of energy
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Many forms of energy exist, but they all fall into two basic categories:
Kinetic energy
Potential energy
Gravitational energy is energy stored in an object's height.
Chemical energy is energy stored in the bonds of atoms and molecules
Nuclear energy is energy stored in the nucleus of an atom
Mechanical energy is energy stored in objects by tension. Compressed springs and stretched rubber bands are examples of stored mechanical energy.
Motion energy is energy stored in the movement of objects.
Sound is the movement of energy through substances in longitudinal (compression/rarefaction) waves
Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance
Electrical energy is delivered by tiny charged particles called electrons, typically moving through a wire.
Radiant energy is electromagnetic energy that travels in transverse waves.
Energy can be converted
To scientists, conservation of energy does not mean saving energy.
Converting one form of energy into another
In reality, converting one form of energy into another form of energy always involves a conversion into useable (or useful energy) and unusable (or unuseful) forms of energy.
Most of our energy is nonrenewable
These energy sources are called nonrenewable because their supplies are limited to the amounts that we can mine or extract from the earth.
Most of the petroleum products consumed in the United States are made from crude oil, but petroleum liquids can also be made from natural gas and coal.
Electricity
Electricity is the flow of electrical power or charge. Electricity is both a basic part of nature and one of the most widely used forms of energy.