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What Is Energy?

Energy Ant

Energy Basics

Learn about the definition of energy, the forms that it comes in, and the difference between renewable and nonrenewable sources.

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Energy Units Basics

How do we compare different types of fuels? One practical way is to convert the physical units of fuels, such as weight or volume, into British thermal units or "Btu." A Btu is a precise measure of the heat content of fuels.

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Periodic Table

Coal, natural gas, and oil are hydrocarbons made up of hydrogen and carbon atoms. Learn more about hydrogen, carbon, and the other chemical elements in this standard periodic table.

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Forms of Energy

Energy forms are either potential or kinetic. Potential energy comes in forms that are stored and includes chemical, gravitational, mechanical, and nuclear. Kinetic energy is energy in movement and includes electrical energy, heat, light, and sound.

Energy Calculators

From gallons to British thermal units (Btu), kilowatthours to megajoules, short tons to metric tons, this handy calculator converts from one energy unit to another.

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