Kayde Ford
Sean Esposito
Waves:
 Waves- a vibratory disturbance that travels through a
material or space [ex: sound, water waves, light, heat
waves
 A wave may be longitudinal, transverse, or a
combination of both, depending on the direction in
which the medium vibrates in relation to the
movement of the wave’s energy.
Waves & Energy
 Waves transfer energy without the transfer of mass
 Waves can be produced in two ways:
 A. Vibration of Particles


Requires a medium for transfer
Mechanical waves
Sounds
Water Drops
EX: Sound, Water waves, Spring Waves
Waves & Energy Cont..
 B. Small changes in the strength of an electromagnetic
field




Requires no medium for transfer
EX: light, microwaves, x-rays
Electromagnetic Wave 1
Electromagnetic Wave 2
Wave Characteristics
In which direction will segment X move as the wave
passes through it?
(1)down, only
(2)up, only
(3) down, then up, then down
(4) up, then down, then up
ANSWER:
(4) Up, than down, than up
Pulses & Periodic Waves
 1. Pulse – single vibratory disturbance that
moves from point to point
 Medium only moves up and down
Pulses & Periodic Waves Cont..
2. Periodic Wave – series of evenly timed
disturbances in a medium
Periodic Waves
PULSE
PERIODIC WAVE
 D. Vibrations and Waves
 Transverse Waves- vibrational disturbance which is
perpendicular to the direction in which the wave travels
 Unlike longitudinal waves,
transverse waves can be oriented in many different planes.
 Ex) water waves, seismic waves, electromagnetic waves (light,
microwaves, radio waves)

Transverse waves
 C. Longitudinal Waves- medium moves parallel to the
direction in which the wave travels
 ex) sound - Guitar String
Characteristics of Periodic Waves:
 Speed Wavelength Frequency-
 Period-(T) –
 Amplitude Crest-
 Frequency (f) = # of Vibrations
seconds
=
# of Cycles
seconds
= Hertz (Hz)
 Cycle= (Single vibration)
 Ex) How many cycles between the dots?
ANSWER:
 3 Cycles
Ex) 10 cycles pass a fixed point
in a wave train in 5 seconds.
What is the frequency of the
wave?
 F= # of cycles
seconds
 f = 10 cycles = 2 cycles
5 seconds
 F= 2 Hertz
1 second
 Sound, frequency is pitch.
 Light, frequency is color.
T
=
1
f
Period : time for an entire wave cycle
to pass a given point in a medium
-determined by source of vibration not
medium
 distance between two consecutive points in phase
 determined by medium
 symbol λ = lambda
 Is the maximum change in position of a particle from
its rest position during a single vibration
 Amplitude of a wave shows the amount of energy in
the wave
 Amplitude is a measure of loudness for sound and
brightness for color
 Amplitude
Phase
"In Phase" (0°) – points on a single periodic wave
that have the same displacement (from
equilibrium position) and moving in the same
direction
Whole number of wavelengths apart
A & E, A & I,
A&M
B & F,
B & J, B & N
Phase
"Out of Phase"– (1800) - same displacement
from equilibrium position but going in a different
direction
½, 1½, 2½ etc wavelengths apart
A & C,
B & D,
F&H
Which 2 points are in phase?
C and F
Name 2 points that are 180° out of phase?
B and D
E and G
QUIZquizQUIZ
 quizquizquiz
quiz
1.
2.
3.
4.
5.
6.
__________________ a vibratory disturbance that
travels through a material or space
__________________single vibratory disturbance
that moves from point to point
_________________series of evenly timed
disturbances in a medium
_____________= #vibrations/sec
_____________– distance between two consecutive
points in phase
___= 1/f
what is a wave?
• the repeating and periodic
disturbance which moves
through a medium from one
location to another is
referred to as a wave. waves
transfer energy, not matter.
Waves are everywhere!
Whether we recognize it or
not, we encounter waves on a
daily basis. Sound waves,
visible light waves, radio
waves, microwaves, water
waves, sine waves, cosine
waves, stadium waves,
earthquake waves, waves on a
string, and slinky waves and
are just a few of the
examples of our daily
encounters with waves. In
addition to waves, there are a
variety of phenomenon in our
physical world which
resemble waves so closely
that we can describe such
phenomenon as being
wavelike.
Transverse and
Longitudinal
Categories of Waves:
Transverse:
Longitudinal:
Characteristics of
Periodic Waves
Amplitud
e:
• The maximum
absolute value of
a periodically
varying quantity.
• Amplitude has
the unit of the
quantity that is
changing (ex.
displacement,
pressure,
field strength,
etc.)
Period:
the time
between
successive
cycles of a
repeating
sequence
of events.
The SI
unit of
period is
seconds.
Formula:
T= t/n (time per
number of cycles)
 the number of cycles of a
repeating sequence of events in
a unit interval of time.
 ƒ = n/t (number of cycles per
time).
 Frequency and period are
reciprocals (or inverses) of one
another.
 The SI unit of frequency is the
hertz.
Two points on a wave
with the same phase
have the same…
 quantity of
disturbance (ex.
displacement) and
 rate of change of
disturbance (ex.
velocity).
Phase is an
angular quantity:
 Adjacent points in
phase are separated by
one complete cycle.
 Adjacent points out of
phase are separated by
half a cycle.
Wavelength
s
Speed!
•the rate of change of
distance with time
•the product of wavelength
and frequency for periodic
waves.
•frequency and wavelength
are inversely proportional.
-Lower frequency waves
have longer wavelengths.
-Higher frequency waves
have shorter wavelengths.
•the speed of a wave is
sometimes known as its wave
speed
•the SI unit of speed is the
meter per second [m/s].
1.What are the two categories of waves?
2.Do lower frequency waves have
shorter or longer wavelengths?
3.What is the SI unit of frequency?
4.What is the formula for period?
5.What is displacement, pressure, and
field strength and example of?
http://paws.kettering.edu/~drussell/Demos/waves/wavemotion.html
http://www.indiana.edu/~emusic/acoustics/amplitude.htm
http://www.qrg.northwestern.edu/projects/vss/docs/Communications/
2-how-are-frequency-and-wavelength-related.html