Energy:
Forms and
Transformations
What is Energy?
• the ability to make things
move or change?
• Energy can exist as either
Kinetic Energy or Potential Energy
(energy of Motion)
(stored energy)
Solar energy is the radiant energy produced by
the Sun. It is the result of movement of photons
and electrons in electromagnetic radiation.
Electrical energy is the movement of elections
generally through a wire. Lightning and static
electricity are examples of electrical energy that
occur naturally.
Thermal energy is energy that comes from heat
due to the random motion of molecules, atoms
and particles in a substance.
Elastic energy is stored energy in
expanded (stretched) or compressed
(squashed) objects.
Chemical Energy is energy stored in the bonds of chemical
compounds (atoms and molecules). Chemical energy is
released in a chemical reaction, often in the form of heat.
Such reactions are called exothermic. Batteries, biomass
(food), petroleum, natural gas, and coal are examples of
stored chemical energy
Sound is the movement of energy through substances in
longitudinal waves. Alarms, music speech all use sound
energy.
Nuclear energy is the energy stored in the nucleus of an
atom. Nuclear energy is unusual in that it can give off
energy in the form of light or heat, but it is the change in
the atom's makeup that produces the energy.
Submarines, power plants, and smoke detectors all use
nuclear energy. Nuclear power plants use uranium, a
radioactive element, to create electricity.
Gravitational energy is stored energy in
raised objects. It is the result of an
objects position relative to the earth or
another object.
Magnetic energy is the attraction of objects
made of iron. Compass, refrigerator magnets
use magnetic energy. Any type of energy source
that uses a generator in the process to make
electricity uses magnetic energy.
Mechanical energy is due to an objects motion
or position. Therefore it is the total amount
of kinetic and potential energy in a system.
Wind-up toys and grandfather clocks are
examples of mechanical energy.
All forms of energy falls under
two categories:
POTENTIAL
Stored energy and the energy of
position (gravitational).
KINETIC
The motion of waves, electrons,
atoms, molecules, and substances.
CHEMICAL ENERGY
stored in the bonds of atoms and
molecules.
NUCLEAR ENERGY
stored in the nucleus of an atom
RADIANT/SOLAR ENERGY
Movement of electromagnetic radiation
THERMAL ENERGY or heat
The vibration or movement of atoms
and molecules in substances.
ELASTIC ENERGY
stored in the compression and
stretched of an object
GRAVITATIONAL ENERGY
energy of place or position.
MECHANICAL ENERGY
movement of parts or a substance from
one place to another.
SOUND
movement of energy through longitudinal
waves.
ELECTRICAL ENERGY is the
movement of electrons.
Describe the process of energy
transfer.
• Energy transfer happens when energy moves
from one object to another.
• Example: When the golfer swings a golf club,
the moving club has mechanical energy.
When the club hits a golf ball, some of the
energy of the club is transferred to the ball,
causing the ball to move.
Energy Transfer Tree.
PE
Gravitational
energy
PE
KE
Mechanical
energy
KE
PE
Elastic
energy
Sound
energy
Sound
energy
Heat
energy
PE
PE
PE
As the ball
goes up gravity
slows it down
causing the
transformation
of KE to PE.
K
PE
As the ball falls
it speeds up
causing the
transformation
of PE to KE.
KE
KE
KE
What is energy transformation?
• This occurs when energy changes from one form to
another
• This allows us to use energy in different ways
• Examples:
– Green plants transform electromagnetic energy into
forms of sunlight into food. The food is stored chemical
energy
– A flashlight changes chemical energy stored in a battery
into electrical energy and then into light and heat.
What is the Law of Conservation
of Energy
• Energy is not created or destroyed. It changes
from one form to another.
• The amount of energy before the transfer is
always equal to the amount of energy after the
transfer.
• Transfer of energy from one object to another
is never 100%
• Energy that is not useful in the transfer is
released into the environment as heat, light,
sound, etc…
Law of Conservation of Energy
Chemical energy in the
battery is transformed
into electrical energy
which is carried
through wires to the
light bulb where it is
transformed into light
energy. Heat energy is
also produce but is
released into the
environment
What is the relationship between
solar energy and photovoltaic cells?