Waves
A disturbance that transfers energy
from place to place through matter or
space
Medium

The matter through
which mechanical waves transfer
energy



Solid, liquid, or gas
The medium doesn’t
move, it vibrates
Electromagnetic waves
do not need a medium – they can
travel
through space
Types of Waves

Transverse – the motion of the
wave disturbance is perpendicular
to the direction the wave is moving
Types of waves

Longitudinal – the motion of the wave
disturbance is in the same direction as
the wave is travelling (parallel)

Sound
Quiz #1 True or False
_____ 1. A wave in the ocean
transfers both the energy and the
water molecules with it.
_____ 2. Liquids are the only type of
matter that can transfer wave
energy.
_____ 3. All mechanical waves
require a medium through which to
travel.
Waves in Motion



Moving waves
Wave Simulator (Volvo)
Wave simulator (Waves on a String)
Wave Properties

Wavelength – the distance between

Frequency – the number of
one crest to the next or one trough to
the next
wavelengths that pass a certain point in
a given amount of time
 Measured
in Hertz (Hz) – waves per
second
 # of pulses or vibrations
 Favorite radio station?
Wave Properties

Amplitude – the maximum distance
the medium moves from the state of
rest
 Shows the amount of energy being
transferred
 Drawing
Seismic Waves

Waves produced by
earthquakes


P waves – Primary
waves that move as
longitudinal waves
S waves –
Secondary waves
that move as
transverse waves
Wave Interactions


Reflection –
occurs when a wave
bounces off a surface
Examples:
Law of Reflection:
the angle of incidence =
the angle of reflection

Wave Interactions

Refraction – the
bending of waves
that travel from one
medium to another
at an angle

Waves travel at
different speeds
through different
media
Wave Interactions

Diffraction – waves will bend
around the edge of a barrier

Interactive Website
Wave Interactions

Interference



Constructive – when two wave crests
are at the same place at the same time
(add)
Destructive – when the crest of one
wave matches with the trough of
another (cancel out)
Interference Simulation
Sound Waves


Travel as longitudinal waves
Can only travel through a medium


Increase amplitude = energy ?




Solid, liquid, gas
Decibel (dB)
Increase frequency = ?
Speed of sound
Doppler Effect
Electromagnetic Waves




Travel as vibrating electric and
magnetic fields
Light travels as both a wave and a
particle (photons)
Do not need a medium to transfer
energy – Why?
Speed of light

All electromagnetic waves travel at the
same speed

Transparent

Translucent

Opaque

Luminous

Illuminated
Visible Light

Luminous – an object that produces
its own light


Examples:
Illuminated – an object that reflects
light

Examples:
Interaction of Light and Objects



Transparent – objects that transmit
most light
Translucent – objects that scatter
light
Opaque – objects that absorb most
of the light that strikes them (color)

What will happen to a plant if only
green light is shined on it?
Mirrors and Lenses

Mirror – flat or curved piece of glass
with a coating of silver metal on the
back

Reflects most light

Lenses – Transparent material that
refracts (bends) light rays

Concave

Convex

Interactive lens