What is energy? Energy is the ability to do work Potential energy The energy stored in objects because of their position Gravitational Potential Energy.

• What is energy?• Energy is the ability to do work• Potential energy• The energy stored in objects because of

their position• Gravitational Potential Energy• Using force to do work against gravity• The energy is stored until gravity can

do work on it and pull it down to the ground

• Kinetic energy• The energy in objects that are in motion

How is it different from kinetic energy?

Potential energy is stored energy while kinetic energy is the energy of motion. When potential energy is used it is converted into kinetic energy. You can think of potential energy as kinetic energy waiting to happen.

The green ball has potential energy due to its height. The purple ball has kinetic energy due to its velocity.

Forms of Energy

Mechanical Energy• The energy of something that is in motion or can be

in motion

• Since potential and kinetic energy can easily switch between them we measure the combined energy and classify it as mechanical energy.

• When the work is done upon the object, that object gains energy.

• The energy acquired by the objects upon which work is done is known as mechanical energy.

• Thermal• The kinetic energy due to the random motion of the

particles that make up an object• Thermal energy is related to the temperature of an

object.• Since heat is known as a process, objects cannot

contain heat. Objects contain thermal energy.• When thermal energy is transferred from or to an

object, it is called heat.• Unlike other forms of energy, thermal energy is

difficult to convert to other forms of energy.

• Thermal• Which would have more thermal energy; an ice

cube, a lake, or a boiling pot of water?• The lake because it has so many more particles

than the other two therefore more thermal energy.

• Chemical• The energy of a compound that changes as its

atoms are rearranged• Chemical energy is a form of potential energy• Chemical energy is stored inside a substance or

object until it is involved in a chemical reaction.• The total energy depends on the arrangement of

the atoms in a compound

Chemical• Which has more chemical energy; water or sugar?• Sugar has more chemical energy because of its

large molecules (C6H12O6)

• Chemical

• Electrical Energy• The potential energy of moving electrons• This energy is generated by the movement of

positive and negative particles or electricity.• Static electricity occurs when the electrons from

one object jump to another object.• Lightning is an example of electrical energy

found in nature.

Direct Current

• Alternating Current• Electrical energy is produced when magnets are

moved through coils of wire

• Sound Energy• The transmition of vibrating energy through the air• A vibrating object causes the particles around it

to vibrate. This kinetic energy is transmitted to our ears and we hear sound

• Sound Energy• Sound produces a relatively low level of energy

when compared to other forms of energy.• There is no sound in space because there is no

object for sound to travel through.• Sounds travels through a solid much faster than

through air.

• Light Energy• The kinetic energy produced by the vibrations of

electrically charged particles• Light is a type of electromagnetic energy.• Light energy is always moving and can therefore not

be stored.

• Light Energy• Light is made of tiny photons

e−

• Forms of Energy

• Light Energy• The energy produced by the vibrations of

electrically charged particles

e−

• Light Energy• The energy produced by the vibrations of

electrically charged particles

e−Photon of light

• Nuclear Energy• The potential energy that comes from changes in

the nucleus of an atom• Atoms store a tremendous amount of potential

energy because of the position of the particles in the nucleus

• When the nucleus of an atom is “split” we have nuclear fission• This is the same energy given off by an

atomic bomb

• Nuclear Energy• There are roughly 430 nuclear power plants

worldwide.• Nuclear energy itself is not dangerous but the way

in which it is generated gives off harmful waste products.