Class Agenda 9.12.07

1
Class Agenda 9.12.07

• 15-20 minute class review using the Kansas City
  Unit Mapping Activity (Mrs. Leach)
• Remind students that they will be given a short
  content quiz or check tomorrow. It will be four
  questions long (worth 50 points)
• Have students spend the last 20 minutes of class
  outlining Chapter 15.2, pages 453-456.
• Tell students that a test over the entire chapter
  will be given on Friday.
• On Friday, I will pass back lab journals. You can
  keep them or put them back in the file cabinet
  assigned to your class period.

2
Chapter 15.2 Outline (pg. 1)

• A. Energy Conversions
• 1. Energy can be converted from one form to
  another.
• a. The process of changing energy from one form
  to another is energy conversion.
• 2. When a match is rubbed a rough surface, it
  catches on fire.
• a. Energy is converted from one form to another
  in a series of steps.
• b. Lighting a match involves several steps before
  the match is ever lit.
• c. For example, mechanical energy used when you
  move the match across a rough surface causes
  friction between the match and the box. Chemical
  energy is released cause the match to erupt in
  flames. This causes thermal energy to be
  released.

3
Chapter 15.2 (pg. 2)

• B. Conservation of Energy (Model of a Chapter
  Outline)
• 1. When energy changes form, the total energy
  stays the same.
• a. The law of conservation states that energy
  cant be created or destroyed.
• b. Energy can be converted, but not destroyed.
• c. For example, a moving car converts chemical
  energy to electrical energy, which is converted
  to heat energy. When the car stops, it cools down
  and the thermal energy becomes apart of the
  system that we live in.
• 2. Friction within machinery reduces efficiency.
• a. Friction causes vehicles and other types of
  machinery to consume more energy.
• b. Friction can be reduced, but it cant be
  avoided because it is all around us.
• c. For example, objects moving through air are
  subject to friction because the air presses up
  against them and slows them down.

4
The Outline Continued 15.2 (pg. 3)

• C. Energy Conversions
• 1. Kinetic Energy and Potential Energy are
  probably one of the most common types of energy
  conversions.
• a. The gravitational potential energy of an
  object is converted to the kinetic energy of
  motion as the object falls.
• b. For example when a diver is standing on the
  diving board, she has plenty of stored energy
  that isnt moving, yet. When she jumps, the
  stored energy becomes activated.
• 2. Even gulls and other living organisms use
  energy conversion to obtain food.
• a. Gulls have learned to use potential
  gravitational energy to feed off of oysters.
• b. For example, the gull increases the
  gravitational energy of the oyster by increasing
  its height off of the ground. Then, it drops the
  oyster, cracking its shell when it hits the
  rocks.
• 3. Kinetic Energy and potential energy undergo
  constant conversion as a pendulum swings.
• a. At the highest point in its swing, the
  pendulum is motionless for just a little while.
  At this point, the pendulum has zero joules of
  kinetic energy.
• b. At the bottom of the swing, the pendulum has
  maximum kinetic energy.
• c. Eventually, frictional forces slow down the
  pendulum. In a clock, springs or hanging weights
  keep the pendulum swinging.
• d. In the case of a pole vaulter, her kinetic
  energy is turned partially into elastic energy,
  as she uses the flexibility of the pole to help
  her get over the bar.

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Chapter 15.2 Outline (pg. 4)

• 3. Kinetic Energy and potential energy undergo
  constant conversion as a pendulum swings.
• e) As she moves through the air, her kinetic
  energy decreases while her potential energy
  increases. As she falls towards the ground, her
  kinetic energy increases, as her potential energy
  decreases.
• f) When friction is small enough to be
  unnoticeable, an objects mechanical energy
  remains unchanged.
• g) Mechanical Energy equal potential and kinetic
  energy.
• h) (KE PE) at the beginning (KE PE) at the
  end
• D. Energy and Mass
• 1. Albert Einstein developed the theory of
  relativity.
• 2. Einsteins equation, Emc2

6
Energy and Energy Transformations

• 9.14.07
• KCCT-Like Test
• Part 1
• 8 Multiple Choice Questions
• 1 Open Response Question