Download Energy Notes

Energy Notes
Energy
• Energy is the ability to do work or make things
change.
• Energy occurs in two main types:
– Potential
• Gravitational, Chemical, Electrical, Nuclear, Elastic
– Kinetic
• Electrical, Thermal, Light, Sound, Wind
Kinetic Energy
• Kinetic energy is energy of motion.
– Only moving objects have kinetic energy
Kinetic Energy
• A person running has kinetic energy.
Potential Energy
• Potential energy is energy based on position,
shape, or condition
– Sometimes referred to as “stored” energy
Potential Energy
An object on a high
shelf has greater
potential energy than
one placed on a
lower shelf.
Large molecules, such
as sugar, have greater
potential energy than
smaller molecules,
such as carbon dioxide
and water.
SUGAR
(C6H1206)
A stretched elastic
band has greater
potential energy
than one that isn’t
stretched.
H20
CO2
Energy Conversion
• To convert something is to change it into
another form.
• Energy can be converted into different forms,
but the amount of energy stays the same.
– Law of Conservation of Energy: Energy cannot be
created or destroyed, only the form can change.
Potential to Kinetic Conversion
• Potential energy can be
converted to kinetic energy.
– Potential energy stored in a
battery can be converted to
kinetic energy in an electric
motor.
• The change happens the
moment the object begins to
move.
Kinetic to Potential Conversion
• Kinetic energy can be converted to potential energy.
– A windmill’s kinetic energy can be converted to potential
energy as it charges stored batteries.
Kinetic to Potential Conversion
• The transformation begins when the object
enters a position with potential energy
– A MOVING OBJECT MAY STILL HAVE POTENTIAL
ENERGY!!
Mechanical Systems
• A mechanical system is an arrangement of
parts that work together.
• Simple mechanical systems use potential and
kinetic energy
– Roller coaster
– Pendulum
Energy Conservation
• Energy is not lost or gained when it is
transferred from potential to kinetic.
– Energy is CONSERVED.
Mechanical Systems and Energy
Conversion
Mechanical Systems and Energy
Conversion
Energy Conservation
• As an object falls, potential energy decreases
and kinetic energy increases.
Energy Conservation
• As an object is raised, potential energy
increases and kinetic energy decreases.
Thermal Energy
• Energy can be transferred from place to place
• Heat is given off when an object’s thermal
energy is transferred.
– Conduction
– Convection
– Radiation
Conduction
• Conduction is the transfer of heat energy
(thermal energy) by direct contact between
particles.
Convection
• Convection is the transfer of heat energy
(thermal energy) through liquids and gases by
moving particles.
Radiation
• Radiation is the transfer of heat energy
(thermal energy) by waves.
Thermal Energy