Define
mechanical
waves and relate
the waves to
energy.
Mechanical waves are disturbances in matter which need a medium to travel through.
These waves also carry energy from place to place. For example, if you are laying on a
boogie board in the ocean and a wave (which has the energy) comes along, both you and
the boogie board will go up. When you are at the top of the wave you have potential
energy, but when you start to move the potential energy gets transferred into kinetic
energy.
Describe transverse,
longitudinal, and
surface waves. Discuss
how they are produced.
Types of Waves
How the Waves are Produced
transverse waves
These waves are produced when a medium (what the wave travels
through) is caused to vibrate at right angles to the direction that the
waves are traveling.
longitudinal waves
These waves are produced when a medium (what the wave is traveling
through) vibrates in a parallel motion to the direction the waves are
traveling.
surface waves
These waves are produced along a surface separating two or differing
media.
Identify
examples of
transverse and
longitudinal
waves.
Types of Waves
Examples of Waves
transverse waves
• shaking a blanket or a sheet up and down making sure that if you start
from the crest or trough you end in the crest or trough
• light waves
longitudinal waves
• sound waves
• hitting a bell
• a crystal wine glass
• a spring door stop
Analyze the motion of
a medium as each
kind of mechanical
wave passes through
it.
Types of Mechanical Waves
The Motion of the Medium as Each Wave Passes
Through it
transverse waves
As a transverse wave passes through, the medium will vibrate at a right
angle to the direction that the wave is traveling.
longitudinal waves
surface waves
As a longitudinal wave passes through, the medium will vibrate parallel
to the direction that the wave is traveling. The motion of this wave also
travels in compressions (where particles are close together) and
rarefactions (where the particles are spread out).
As a surface wave passes through, this wave travels along a surface
separating two or differing media.
Define frequency, period,
wavelength, and wave
speed. Describe these
properties for different kinds
of waves.
Unit 5-2
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Frequency – The number of cycles completed in a given amount of time (usually one second).
period – The time needed for one complete cycle that returns to its starting point.
wavelength – The distance between two points, a point on one wave and the same point on the
cycle of the next wave.
wave speed – distance/time
Describing These Properties For Waves
To find the wave speed, you have
to find the distance of the wave
and divide it by the time it takes
for the wave to reach that
distance.
The top bars on this wave
represent the crest and the
bottom bars represent the trough.
So from one crest or trough bar to
the other is the period because it
is a complete cycle that returns to
its starting point.
From one point on
a wave to the to
that same point on
the next cycle of
the wave is the
wavelength.
Example A would have a higher
frequency than example B. This is
because A has more cycles per one
second than B does, which means that
the waves are moving faster in example
A.
Unit 5-2
Describe how to
measure amplitude and
relate amplitude to the
energy of the wave
To measure amplitude you have to find the height of a wave from its resting position. The greater
amount of energy that the wave has, the greater that the wave’s amplitude will be.
Describe how
reflection,
refraction,
diffraction, and
interference
affect waves.
Unit 5-3
Terms That Deal With Waves
How They Affect Waves
reflection
It may cause the wave to be flipped upside down.
refraction
As a wave enters a new medium at an angle, refraction causes the wave
to bend.
diffraction
As a wave moves around or passes through a narrow object or obstacle,
diffraction causes the wave to bend.
interference
Interference is when two or maybe more waves overlap and then
combine together.
Unit 5-3
State a rule that
explains refraction
of a wave as it
passes from one
medium to another.
A rule that explains refraction of a wave as it passes from one medium to another is that when a
wave is going into a new medium at an angle, refraction takes place because one side of the
wave moves more slowly than the other side.
Unit 5-3
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All
the type of medium that the wave is traveling through
the type of wave
the angle that the wave moves from one medium to another
Refraction Only
how much the wave bends
the speed of the waves
Diffraction Only
the size of the opening or obstacle
the size of the wavelength
Interference Only
how much the waves overlap and combine together
Identify factors that
affect the amount of
refraction,
diffraction, or
interference.
Unit 5-3
Distinguish between
constructive and
destructive interference
and explain how
standing waves form.
The difference between constructive and destructive interference is that constructive interference
is when two waves combine to produce a wave with a greater amplitude and destructive
interference is when two waves combine and produce a wave with smaller displacement.
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constructive interference – When two waves combine, the crests of those waves will combine to
produce a higher crest and the two troughs will combine to produce a lower trough.
destructive interference – When two waves combine , the crest of one wave will meet the trough
of the other wave and result to have a crest lower than the crest of both of the waves (one or two).
At certain frequencies, as a result of interference, two waves traveling in opposite directions can
produce a standing wave.
Describe the properties
of sound waves and
explain how sound is
produced and
reproduced.
Unit 5-4
Sound Wave Properties
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speed
frequency
pitch
intensity
loudness
Sound is produced when a medium is disturbed and the molecules in the medium are set into motion. To reproduce sound, you convert the
electronic signals into sound waves.
Unit 5-4
Describe how sound
waves behave in
ultrasound and music
In music, by changing the frequency of standing waves, the pitch that comes out will vary. So in a
wind instrument the notes can either be opened or closed and depending on the length of the
column of air, standing waves (sound waves) are produced. In string instruments, you can either
make the strings longer or shorter using your fingers to get standing waves (sound waves).
An ultrasound is sound at frequencies higher than almost every one hears. In sonar (which
ultrasound is used in), waves are sent out and the distance to that object is calculated by using
the speed of sound in water. When the sound waves reach an object, they bounce off and send
back an echo that says where something is located.
Unit 5-4
Explain how relative
motion determines
the frequency of
sound an observer
hears.
Relative motion determines the frequency of sound an observer hears because for instance in the
Doppler Effect, as any source of sound approaches, the observer would hear a higher frequency.
When the source of sound moves away, the observer would hear a lower frequency.
Unit 5-4
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Analyze the
functions of the
main regions of the
human ear.
outer ear – gathers while focusing sounds to the middle ear
middle ear – receives and amplifies vibrations
inner ear – senses vibrations while using nerve endings and sends signals to the brain