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Unit 1 Lesson 1 Waves
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 1 Waves
B.I - Waves transfer energy
and interact in predictable
ways.
E.Q - What are waves?
Unit 1 Lesson 1 Waves
What are waves?
Riding the Wave
p6
• Waves are disturbances that transfer energy
from one place to another.
• Travel by disturbing (vibrating)
a medium.
• A medium is the material
through which a wave can
travel.
• Waves TRANSFER ENERGY
• Some waves, such as ocean
and sound waves, transfer
energy through a medium.
• Some waves, such as light
waves, can transfer energy
without a medium.
Unit 1 Lesson 1 Waves
Different Ways to Transfer Energy p7
How does a wave transfer energy?
When a wave moves through a
medium, particles that make up
the matter of the medium
vibrate, causing the nearby
particles to start vibrating, but
they DO NOT change their
position (much).
Instead the particles return to
nearly the same spot they had
been in originally.
Unit 1 Lesson 1 Waves
Riding the Wave
p8
How does a wave transfer energy?
• Not all waves transfer energy the same way.
• Waves can be classified by comparing the direction
that they cause particles in the medium to move with
the direction in which the wave moves.
Longitudinal
Transverse
Unit 1 Lesson 1 Waves
p8
How do waves transfer energy?
• Energy can be transferred from one object to another using
compressions, when the coils are close together, and rarefactions,
when the coils are far apart.
• This causes energy to travel in a longitudinal wave.
• Longitudinal waves move the medium parallel to the direction in
which the waves travel.
• Sound waves are longitudinal waves.
Unit 1 Lesson 1 Waves
p9
How do waves transfer energy?
• Energy can be transferred from one object to another
using up and down motions. This causes energy to travel
as a transverse wave.
• In a transverse wave, particles move perpendicular to
the direction the wave travels.
The points where a wave is highest are
called crests.
The points where a wave is lowest
are called troughs.
P8-9
Unit 1 Lesson 1 Waves
p10
Making Waves
What are some types of waves?
• Waves can also be classified by what they are travelling
through.
• Waves that require a medium, such as water waves, are
called mechanical waves.
• Some mechanical waves can travel through more than
one medium.
• Waves travel at different speeds in different media.
• Mechanical waves can’t travel without a medium.
Unit 1 Lesson 1 Waves
p10
What are some types of waves?
• Light and similar waves are called electromagnetic
(EM) waves. An electromagnetic wave is a
disturbance in electric and magnetic fields.
• Do not require a medium to travel.
• Sunlight is an example of EM waves. Other examples
include radio waves, microwaves, and X-rays.
• In empty space(vacuum), all EM waves travel at the
same speed, called the speed of light
• 300,000,000 m/s
Unit 1 Lesson 1 Waves Visualize
Sunlight is a(n)
Water waves are
A towel waving displays a(n)
Vocal sounds are
Music is a(n)
Firelight is a(n)
it! Pg 11
p11
Unit 1 Lesson 1 Waves Visual
Summary
p12
15) The water particles in the wave move to
the right, along with the wave
The water particles in the wave
move mostly up and down
16) The toy above and the toy
below both show longitudinal
waves The toy above shows a longitudinal wave, but
the toy below shows a transverse wave
17) This picture shows only examples of mechanical waves.
This picture shows mechanical waves
(ocean waves) and electromagnetic
waves (light – EM spectrum)
Unit 1 Lesson 1 Waves Visual
Summary
p12
18) Use the example to support the following statement:
Waves transfer energy but not matter.
A toy on the surface of the pool of water will bob up and
down as waves pass.