Forms of Energy
•  How do potential energy and kinetic
energy differ?
•  How are mechanical energy and
thermal energy similar?
•  What two forms of energy are carried
by waves?
Energy
•  Energy influences everything in your
life, including the climate, the economy,
and your body.
•  Scientists define energy as the ability
to cause change.
Potential Energy
•  Potential energy is stored energy due
to the interaction between objects or
particles.
•  Objects have potential energy if they
have the potential to cause change.
Objects have gravitational potential energy
if they have mass and height above
Earth s surface.
Potential Energy (cont.)
•  Chemical energy is the energy stored in
and released from the bonds between
atoms.
•  Your body breaks chemical bonds in
foods and converts the released energy
into other forms of energy that your body
can use.
Potential Energy (cont.)
•  The energy stored in and released from
the nucleus of an atom is called
nuclear energy.
•  The Sun s energy is released through the
process of nuclear fusion, during which
the nuclei of atoms join together and
release large amounts of energy.
Kinetic Energy
•  Kinetic energy is energy due to motion.
•  An object s kinetic energy is related to
the mass and the speed of the object.
•  The energy in an electric current is
electric energy.
Combined Kinetic Energy and
Potential Energy
The sum of the potential energy and the
kinetic energy in a system is
mechanical energy.
mechanical
from Greek mēchanē, means
machine
Combined Kinetic Energy and
Potential Energy (cont.)
•  An object s thermal energy is the sum
of the kinetic energy and the potential
energy of the particles that make up the
object.
•  Thermal energy of an object increases
when the potential energy, the kinetic
energy, or both increase.
Energy Carried by Waves
•  A wave is a disturbance that transfers
energy from one place to another without
transferring matter.
•  Sound energy is carried by sound
waves.
•  The energy carried by electromagnetic
waves is radiant energy.
Electromagnetic waves often are
described by their wavelengths—the
distance from one point on a wave to the
nearest point just like it.
Visible light is one form of radiant energy.
•  Objects can have potential energy
(stored energy) and kinetic energy
(energy due to movement).
•  Mechanical energy is due to largescale motions and interactions in a
system. Thermal energy is due to
atomic-scale motions and interactions
in particles.
•  Two kinds of energy carried by waves
are sound energy and radiant energy.