Warm Up

1
Warm Up

• YOU WILL TURN THIS IN SO WRITE ON A SEPARATE
  SHEET OF PAPER.
• You may not use your notes. Treat this as a quiz
• Match the following forms of energy with their
  descriptions

• ___1. Sound Energy
• ___2. Chemical Energy
• ___3. Electrical Energy
• ___4. Thermal Energy
• ___5. Nuclear Energy
• ___6. Light Energy

• the energy associated with the nucleus of an atom
  
• the energy caused by an objects vibrations
• the total energy of the particles that make up an
  object
• the energy produced by the vibrations of
  electrically charged particles
• the energy of a compound that changes as its
  atoms are arranged to form new compounds
• the energy of moving electrons

2
Energy Conversions

• How is energy converted from one form to the
  next? Can you identify all of the forms of
  energy during an energy conversion?

3
Kinetic to Potential and Back

• Situation Shark jumping
  out of the water!
• A. Shark jumping out of water ? B. Shark at the
  apex of its jump ? C. Shark falling back to
  water
• A. Kinetic Energy ?
  B.Potential Energy ? C.
  Kinetic Energy

4
Pendulum

• A Pendulum is a mass hung from a fixed point so
  it can swing freely.
• When the pendulum is lifted and is at rest the
  energy is stored as potential energy.
• When the pendulum is
• let go the potential
• energy is converted into
• kinetic energy.

PE
KE
Energy Conversion Diagram Potential Energy ?
Kinetic Energy
5
ENERGY CONVERSIONS/TRANSFORMATIONS

• Transfer of energy
• Change from one form to another
• Can be converted to more than one form
• Total amount of energy always stays the same!
  (Law of Conservation of Energy)

6
More Energy Conversions in a Pendulum!
D.
A.
B.
C.
7
Conversions Involving Chemical Energy

• Food ? A person eating the food digesting it
  for use in the body
• Energy Conversion Diagram
• Chemical Energy ? Kinetic Energy Thermal Energy

8
Where does the chemical energy in food come from?
Energy Conversion Diagram Heat Light Energy
from Sun? Chemical Energy in Food
9
Where does the heat and light energy from the sun
come from?
Energy Conversion Diagram Nuclear Energy from sun
? Heat Light Energy
10
Conversions involving Electrical Energy

• Electric energy comes to us in a couple of ways.
• Batteries store potential chemical energy that
  generates and electric current.
• Batteries Chemical ? electric
• Powerplants Chemical energy (fossil fuels)?
  kinetic energy (wind water)? electric energy
• Powerplants nuclear energy ? thermal energy
  (steam) ? electrical energy

11
Conversions involving Electrical Energy

• Regardless of how it is generated the flow of
  electric charge is converted into other forms to
  make our lives easier and more enjoyable.
• Examples just look around your home! Electrical
  energy is being used everywhere.
• TV Electrical Energy ? sound light, thermal
• Your Cell Phone
• chemical ? electrical light, sound,thermal

12
Conversions Involving Electrical Energy(Match
the Conversion to the Example)
B
D
A. Chemical to Electrical, kinetic, sound
B Chemical to Electrical light sound thermal
C
A
C. Electrical to Light and Thermal
D. Chemical to electrical
13
Energy and Machines

• A machine can make work easier by changing the
  size and/or direction of the force required to do
  the work

14
Energy and Machines

• When riding a bike you transfer your kinetic
  energy to the pedals
• From the pedals, energy is transferred to the
  chain
• From the chain, energy is transferred to the
  wheels
• Wheels do work on the surface youre traveling on

Energy Conversion Diagram Your Kinetic Energy ?
Pedal ? Chain ? Wheels ? do work on the surface!
15
Machines Convert Energy

• Devices that convert energy from one form to
  another are machines. Machines make our lives
  easier by allowing us to direct energy into
  useful work.
• HOWEVER! No machine can ever make the total
  amount of work that has to be done decrease.
• Chemical energy can be converted into to other
  types of energy such as
• Thermal, electrical, nuclear, kinetic, etc

16
Why is Converting Energy Important?

• And no machine can ever be 100 efficient. Some
  energy in every conversion is wasted to overcome
  friction.
• The efficiency of a machine can be calculated
  with the formula
• (Work output/Work input)x100

17
Why is converting energy important

• Using machines to convert energy allows us to
  turn energy into a form that we need or can use
• Efficiency- comparison of how much energy you
  have before a conversion to the amount of useful
  energy you have after a conversion
• Some energy is ALWAYS converted to thermal
  energy!