Barrons AP Environmental Science

8: Energy

ENERGY CONCEPTS

Energy is the ability to do work. In the SI system, the unit of energy is the joule.
Power is work divided by time. The unit of power is the joule/s, which is also
called a watt. The following table describes the different forms of energy.

Forms   of  Energy

Form Description

Mechanical There    are two types   of  mechanical  energy:

potential   energy  (a  book    sitting on  a   table)  and

kinetic energy  (a  baseball    flying  through the air).

Thermal Heat    is  the internal    energy  in  substances—the

vibration   and movement    of  the atoms   and

molecules   within  substances.

Chemical Chemical   energy  is  stored  in  bonds   between

atoms   in  a   molecule.

Electrical Electrical   energy  results from    the motion  of

electrons.

Nuclear Nuclear energy  is  stored  in  the nuclei  of  atoms,

and it  is  released    by  either  splitting   or  joining

atoms.

Electromagnetic Electromagnetic energy  travels by  waves.

Power and Units

Power is the amount of work done per time. The most common unit of power is
the kilowatt-hour (kWh).

Units   of  Energy/Power