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Unit: Types of Energy
Sections: Potential Energy
Kinetic Energy
Heat and Temperature
Key Words:
Mechanical
energy
Hydroelectric
power
Degree
Mechanical
advantage
Chemical
reaction
Calorie
(heat
energy)
Kinetic
energy
Stored
energy
Radiant
energy
fahrenheit
Celsius
Boiling
point
Physical
property
Thermometer
(weather)
Friction
Potential
energy
Entropy
Diffusion
Energy
(physical)
Melting
point
Thermal
energy
Essential Questions (by Section):
Potential Energy
- What is potential energy and what are some examples of it?
- What are types of potential energy?
- What is the difference between potential energy and kinetic energy?
- How does potential energy turn into kinetic energy?
Kinetic Energy
- What is kinetic energy?
- What are some examples of kinetic energy?
- How does kinetic energy turn into potential energy?
Heat and Temperature
- What is the difference between heat and temperature?
- What happens to the molecules of a substance when heat is added to it?
- Which types of measurements are used to describe quantities of heat and temperature?
- How can heat be transferred from one object to another?
- How is energy transferred between objects or systems?**
Potential Energy
Energy – the ability to do work or cause change
o Potential energy
 energy an object has due to its position or chemical composition
 energy that is “stored” until it can be converted to kinetic energy
System
- all the parts of an energy system
o uses energy
 ability to do work
o uses “forces”
 a push or pull
- has both PE and KE
- PE depends upon position and condition
Energy
transfer
Conduct
Convection
(heat)
energy stored between
bonds of atoms
CPE - chemical PE
changes to heat when an
object burns
changes based on location
of elevation
Potential Energy
GPE - gravitational PE
ex. skier on top of a
mountain
stored energy by electron
movement
ElPE - electric PE
ex. batteries - to + poles
stored energy in the
nucleus of atoms
NPE - nuclear PE
fission - splitting of atoms
fusion - combining of
atoms
energy stored as an object
is stretched (tension force)
EPE - elastic PE
ex. rubber bands
Kinetic Energy
Kinetic energy


energy an object has due to its motion
includes:
 heat (vibrational, rotational, translational motion of atoms)
 electrical (motion of electrons)
 Sound (wave motion of oscillating particles of matter)
 Any motion of objects
 Even when “standing still” molecular movement is still vibrating
 Absolute zero – where all molecular motion stops

Temperature – a measure of kinetic energy
o DIRECTLY PROPORTIONAL
Higher
temps
Higher
KE
KE – object has due to motion
- KE = ½ mv2
o KE = one half * mass of the object * the object’s velocity squared
o Ball is 100g (mass), moving at 25 m/s – what is the KE?
 ½ (100g)(25)2
 ½ (100g)(625)
 ½ (62500)
 KE = 31,250 J (J = Joules = Kg*m/s –> units of energy)
- Law of conservation of energy
o KE is transferred from one object to another
o Ex. bat hits a ball -- > the KE of swinging the bat transfers to the ball
 Ball goes flying through the air
o Ex. skier going up a lift to the top of a mountain
 the lift provides the KE
 building GPE due to height of the mountain
 GPE increases as any object increases altitude
- other forms of KE
o electricity
 generators move water or steam by spinning turbines
 converts mechanical energy to electrical energy
Law of conservation of energy
o How it applies
 Energy is continually changing from kinetic to potential and potential to kinetic
 During conversions, energy is always “lost”
 Never 100% efficient
 Lost as “heat” (another form of energy)
 Ex. Picking up a ball from the ground
o Some energy from your body is converted to GPE (gravitational
potential energy) in the ball
o
o
o
o
Drop the ball, as it hits the ground, KE is converted to sound and heat
Shape of ball has PE called “elastic PE” when ball deforms from impact
Ball springs back into shape converts EPE to KE
Ball does not go as high on next bounce because of energy lost as sound
and heat
Heat and Temperature
Heat – form of energy transferred between objects of different temps
- Transferred or “flows” between objects by:
Conduction
Transfer of heat between 2
objects in physical contact with
each other
Convection
A vertical circulation pattern is
established
Radiation
Heat energy travels through
any medium (atmosphere or
space)
Warmer regions expand and
become less dense (rise)
Faster moving molecules of the
hotter object collide with the
slower moving molecules of
the cooler object – causing
them to move faster and the
hotter to move slower
-
Cooler, more dense material
will move under warmer
(sinking)
amount of work
needed to raise
temp of 1 lb of
water 1 degree
Fahrenheit
Calorie
small - amount
of energy
required to
raise 1 g or
water by 1
degree Celsius
Joules
BTU
Calorie
Can be quantified (given a value)
British Thermal Units
-
Ex. Infrared radiation
Joules
equal to the
energy
transferred or
work done to
move 1 Newton
a distance of 1
meter
Often confused with temp
o Temp – measure of the average kinetic energy of the particles in matter
Transfer of thermal energy
o Thermal energy – kinetic energy or motion energy of particles of matter
-
o Particles can take the form of:
 Translation
 Rotation
 Vibration
Melting and Boiling Points
o Refers to states of matter
 Solid
 Liquid
 Gas
o Unique points for each element, molecule, or compound
Melting
Point
solid
to liquid
Boiling
Point
liquid
to gas