4.1 Properties of Waves
•  A wave is a disturbance or movement that transfers
energy through matter or space.
w  Examples of waves include: water waves, sound waves, and
microwaves.
•  Energy is the capacity to apply a force over a distance.
•  A force is a push or a pull on an object.
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Features of a Wave
•  A crest is the highest point on a wave.
•  A trough is the lowest point on a wave.
•  The wavelength is the distance, in metres, for one
complete cycle of the wave.
w  Crest to crest or trough to trough.
•  The amplitude is the height of a wave crest or depth of a
trough, as measured from its rest position.
Identify each of the
lettered parts of the wave.
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Two Types of Waves
•  The matter that waves travel through
is called a medium.
w  Some waves such as light waves, can
travel through space where there is no
medium.
•  Two types of waves that travel
through a medium are:
w  Transverse wave – matter in the medium
moves perpendicular to direction of the
wave.
w  Compression wave – matter in the medium
moves parallel to direction of the wave.
Transverse wave
Compression wave
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Frequency
•  Frequency is the number of repetitive motions, or
oscillations , that occur in a given time.
•  Frequency is usually measured in hertz (Hz).
•  When the frequency of a wave increases the
wavelength decreases.
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(c) McGraw Hill Ryerson 2007
Frequency Equation
Frequency can be calculated using the following
equation:
frequency = cycles/seconds
Use the above equation to find the frequency for each of
the following:
•  a) A hummingbird flaps its wings 120 times in 3
seconds.
•  b) A DVD spins 35 times in 7 seconds.
Go to the next slide to view the answers
See page 138
(c) McGraw Hill Ryerson 2007
Frequency Equation
Frequency can be calculated using the following
equation:
frequency = cycles/seconds
Use the above equation to find the frequency for each of
the following:
•  a) A hummingbird flaps its wings 120 times in 3
seconds. (40 Hz)
•  b) A DVD spins 35 times in 7 seconds. (5 Hz)
Take the Section 4.1 Quiz
See page 138
(c) McGraw Hill Ryerson 2007