Energy is the ability to do work. In physics, energy is a conserved quantity, and a closed system of interacting particles is known to always have the same value for its energy; this is known as the law of conservation of energy. The SI unit of energy is joule. Energy can be converted into various forms like Potential energy, Kinetic energy and Thermal energy (see below for more).
More generally, energy is a source of usable heat or power.
There are a number of formulas in physics that relate to energy, such as "E=(1/2)mv²", "E=Fd", "E=QV" (charge times voltage), "E=CV²", "E=LI²", and the very famous but not often used in ordinary physics "E=mc²".
Forms of Energy
Energy can occur in various forms:
- Chemical energy
- Internal energy
- Thermal energy
- Kinetic energy
- Nuclear power
- Potential energy
- Electric potential energy
- Span energy
- Radiant energy
There is unanimous agreement from all points of the spectrum that the cheapest, easiest and quickest way to save on energy costs and reduce imported oil is to reduce waste and be more efficient on the consumer side—especially in insulating residences and using more efficient appliances and automobiles. Many local electricity and gas companies have rebate programs; the federal government offers $1500 tax rebates to ordinary Americans, and many states have somilar programs in 2010.
- Wile, Dr. Jay L. Exploring Creation With Chemistry. Apologia Educational Ministries, Inc. 1998
- Halliday, Resnick, Walker: Fundamentals of Physics, 6th Edition
- See "Federal Tax Credits for Consumer Energy Efficiency" 2010; for state rebates see The Database of State Incentives for Renewable Energy (DSIRE)