Here are the steps to solve the roller coaster energy problems: 1. PE at point A = mgh = (20 kg)(10 m/s^2)(250 m) = 50,000 J 2. KE at point A = 0 J (velocity is 0 m/s at the top) 3. ME at point A = PE + KE = 50,000 J + 0 J = 50,000 J 4. KE at point B = 1/2mv^2 = 1/2(20 kg)(200 m/s)^2 = 40,000 J 5. ME at point C = ME is conserved. ME at point A was 50,000 J. 6. PE at

1. 1. Describe the energy transfers
that occur in a light bulb.
2. Describe the energy transfers
that occur when the body is
powered by food.

2. Wt=50N
1. What is the KE at point A? Why?
2. What is the PE at point A?
3. What is the ME at point A?
4. What is the PE at point C?
5. What is the KE at point C?

3. Energy Types
Copy this chart in your notes with enough room to add details. Use
your book to fill in the information.
Type Descriptions/Explanations Examples
Mechanical
Thermal
Chemical
Electrical
Sound
Light
Nuclear

4. 1. Describe the energy transfers
in a hairdryer.
2. What is the difference
between renewable and
nonrenewable energy
resources?

5. Forms Explanation Example
Total energy of
Mechanical
motion and position
Total kinetic energy
Thermal
of particles
Energy stored in
Chemical
rearranging atoms

6. Energy of moving
Electrical
electrons
Energy of vibrating
Sound
particles
Vibrations of electrically
Light
charged particles
Energy in the nucleus of
Nuclear
an atom

7. 1. Mechanical Energy
total energy of motion and position
ME=KE + PE

8. An object on the top of a hill has
high ____ energy and low ____
energy.
As the object rolls down, what
happens?
Why does there seem to be less
energy at the bottom of the hill
than at the top?

9. 2. Electrical Energy
the energy of moving electrons
Like charges repel and
+ +
Opposite charges attract
+ -

10. Two Types of Electricity
Static Electricity
Current Electricity

11. The Power of Electricity
 Can be turned into other kinds of energy
 Can do work
 Hairdryer converts electric to thermal
 Alarm clock converts electric to sound and
light

12. 3. Nuclear Energy
the energy of the nucleus of an atom
 Fission
 Fusion

13. Pros and Cons of Nuclear Energy
Fission Fusion
+ make electrical + fuel is plentiful
energy + only small amounts
+ no carbon dioxide or of radioactive waste
other gases products
- limited fuel supply - not currently
- radioactive waste practical
products - large amount of
- possible release of energy needed to
radioactive material heat and contain the
hydrogen plasma

14. The Sun
Giant nuclear fusion
reactor
Ultimate source of
energy for our planet

15. 4. Chemical Energy
the energy of rearranging atoms
 Is photosynthesis endothermic or
exothermic?
 Is respiration endothermic or
exothermic?

16. 5. Sound Energy
the energy of vibrating particles
-caused by
vibrations &
carried through
a substance.

17. Making Sound vs. Hearing Sound
Have you heard this riddle?
If a tree falls in the forest and no one is around to
hear it, does the tree make a sound?
0
What do you think?

18. When a tree falls and hits the ground, the tree and
the ground vibrate. These vibrations are
transferred to the surrounding air.
0
So there would be a sound!!!

19. Change Frequency = Change Pitch
TRY IT! – Vocal cords
WATCH IT! – Jars vs. Bottles

20. TRY IT!
 Hold the cut rubber band stretched tight.
 Have a partner pluck the rubber band with
their finger.
 Notice the pitch.
 Shorten the length of rubber band by
holding it in the middle.
 What was different??

21. Echolocation

22. 6. Light Energy
the vibrations of electrically charged particles
Called PHOTONS 

23. The EM Spectrum
 Visible light is one portion of
the Electromagnetic Spectrum.
 All of these waves are energy-
filled waves.
 Insects, like bees, see shorter
wavelengths than humans.
What type of EM waves do
they see?
WATCH IT! - prism

24. Possibilities of Light
Light rays move away from their source in straight lines.
When they hit something, they are either
Absorbed Reflected Refracted
(stopped) (bounced off) (bent)
WATCH IT! - Mirror

25. TRY IT!
 Fill beaker half full of water.
 Put a pencil in the glass.
 Look at the pencil through the side of the
glass.
 How does the pencil look different than it did
before you put it in the water?
 This is an example of ______________.

26. TRY IT!
 Prop up the card with the arrow on it.
 Place a glass of water a little to one side of the
card and a few inches in front of it.
 Now stoop down until your eyes are level with
arrow.
 Slide the glass between the card and your
eyes. Try sliding it back and forth a few times.
 What happened? What causes this?

27. Light Source or Not?
You can see a light source even in the dark
because its light passes directly into your
eyes. Most things around you are not light
sources. Why can you still see them?
You can still see them because light from
light sources reflects off the objects and
then travels to your eyes.

28. The Speed of Light
Watch this clip to learn more about the speed of
light.

29. Check your Light Understanding
What is a photon?
On the EM spectrum, what type of EM radiation
has the highest energy – radio waves, gamma
rays, or x-rays?
What are 3 possible things that can happen to
light rays after they leave the source?

30. Sound & Light: Alike, but Different
Sound Light
*vibration *does NOT
*needs a medium need a medium
*longitudinal *transverse

31. 7. Thermal Energy
the total kinetic energy of the particles
 more thermal energy
= faster moving
particles
 less thermal energy
= slower moving
particles

32. Thermal Energy vs. Heat
Heat is the transfer of energy between
objects that are at different
temperatures.

33. Three Kinds of Heat
Conduction Convection Radiation
(touch) (current) (rays)
Hot Cold
Common

34. Check your Thermal Understanding
Is thermal energy kinetic or potential?
If you touch something in which the particles are
moving faster than the particles in your skin, how
would it feel?
When objects have more thermal energy than their
surroundings, what do you predict will happen in
terms of heat?

35. 1. What is heat?
2. How does thermal energy play
a role in the Law of
Conservation of Energy?

36. Bill Nye; Heat
 BEFORE: List the forms of energy that you know
and understand
 DURING: Write notes about heat, conduction,
convection, radiation
 AFTER: Write a paragraph that describes thermal
energy, heat, and the processes of conduction,
convection, and radiation.

37. Roller Coaster Energy Problems
HT=250 m
WT=200N
HT=20 m
WT=200N
M=20kg
V=200m/s
1. Find the PE at point A.
2. Find the KE at point A. Answer the
3. Find the ME at point A. problems on
4. Find the KE at point B. the left on your
sheet under the
5. What is the ME at point C? roller coaster
6. Find the PE at point C. picture.
7. Find the KE at point C.