# Energy

Energy
Energy is a word with more than one meaning.
Energy in Science.
Energy is something that can do work.
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 law of energy".
Example of Conservation Law of Energy.
The measurements of energy at the start and end will always be the same.
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.Adding salt to water will make hydro-power move faster.
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.
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 sâˆ'2.
The energy unit of measurement for electricity is the kilowatt-hour (kWÂ·h). One kWÂ·h is equivalent to 3,600,000 J (3600 kJ or 3.6 MJ)