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Energy
Chapter 14
Prior Knowledge
What is energy?
 What are waves and where are they
found?
 What are the parts of a wave?
 What is light?

14-1
What Are Some Forms of Energy?
1. Energy= the ability to cause change in
matter.
 2. Potential energy= energy that is due to
the position or condition of an object.

 Example:
Skier at top of hill.
Yo Yo before it falls
Newton ball before it is let go.
Water at top of waterfall
Stretched rubber band
Drawing a bow and arrow

3. Kinetic energy = Energy of motion.
Examples: Skier moving down a hill
yo yo moving up and down.
Newton balls moving back and forth
Water flowing down a waterfall
Rubberband flying through the air
Arrow moving towards a target
Examples of Energy
Transformations

1. Fireworks:
-starts as stored chemical energy as a rocket
-moves to kinetic energy at the rocket moves into sky.
-Flash of light is chemical energy
- Sound (bang) is sound energy.

2. Battery:
-starts as chemical potential energy.
- When battery is being used it is electrical energy.
- Heat is produced so it is thermal energy.
-Light shown is light energy.
14-2 What are Waves?
1. Waves are a disturbance that carries
energy through matter or space.
2. Wavelength = distance from middle of
crest to middle of next crest on a wave.
3. Amplitude = distance from resting position
to either the top of crest or bottom of
trough
Sound waves
1.
2.
3.
A single sound wave is made up of one
compression area and one spread area.
Frequency = number of times the string
vibrates in a given amount of time.
(hertz)
Pitch: refers to how high or low sound is.
The higher the frequency or a wave the
higher the pitch.
4. Loudness is measured in decibels (dB).
-The larger the amplitude the louder
the sound.
- Loud sounds can cause pain and
hearing damage.
*wear ear protection to block
sounds above 80 dB.
(airplanes, rock concerts, factories.)
Light and
Electromagnetic Waves
1.
2.
Light is a form of energy that travels in
waves but doesn’t need matter.
Electromagnetic spectrum = all energy
waves that travel at the speed of light in
a vacuum.
-
-
radio, microwaves, infrared, visible, ultraviolet, xray, and gamma rays
Visible light is part of the spectrum that you can
see.
Light Energy from the Sun
-
-
Heat
Makes air flow
Water to evaporate (water cycle)
Produces food for plants, animals, humans
Photosynthesis

Carbon Dioxide
+
Light
Water >>>>>
Glucose +
Chlorophyll
Oxygen
14-3 How Does Light Behave?
1.
Reflection = The bouncing of light off a
surface.
- mirror or still water
- rough surfaces don’t reflect light they
absorb light.
2. Visible light is white.
- when white light passes through a prism, its
path changes, and white light is separated.
**Red Orange Yellow Green Blue Indigo Violet
 Carrot
is orange because all other colors are
absorbed and orange is reflected.
 Black objects absorb all wavelengths of light and
reflect very little light. This is why black top parking
lots are hot.
Refraction and Diffraction
3. Refraction = The bending of light as it
passes from one material to another.
Examples: pencil, straw, or flower in
glass of water.
(light leaves water
and enters air it
speeds up
and bends.)
4. Diffraction = The bending of light around
the edge of an object.
-Particles in the air cause diffraction in
the atmosphere.
-Longer wavelengths
(red) tend to diffract
more often.
5. Transparent = allowing almost all light to pass
through.
Example: colored glass, light covers
6. Translucent = allowing some light to pass
through.
Example: tissue paper, wax paper, some
plastic.
7. Opaque = don’t allow any light to pass through.
Example: metals, clay pots, soil, tree, house