WAVES
Intro 2 min vid
Morgan Freeman weird stuff with waves
Longer half hour on electromagnetic
waves
Objective 1: Relate the
Conservation of Energy to
energy transformations
Describe how energy--mechanical, electrical,
chemical, light, sound, and heat--can be
transformed from one form to another
Show understanding that energy
transformations result in no net gain or loss
of energy, but that in energy conversions less
energy is available due to heat loss.
Objective 2: Relate waves
to the transfer of energy
Relate wavelength to energy
Relate frequency to energy
Relate wavelength to frequency
Describe how waves travel through
different kinds of media
Mechanical waves
Water, Sound, Slinky, etc.
Electromagnetic waves
Describe how waves can be
destructive &/or beneficial
Describe how waves--earthquake waves,
water waves, and electromagnetic waves-can be destructive (harmful) or beneficial
(good) due to the transfer of energy
Destruction (cons)
Benefits (pros)
ALL WAVES
Transfer energy from one
place to another
Energy transferred does NOT have mass.
Actual particles of the wave (such as water
waves) are NOT transferred, but stay in the
same place
Have wavelength, frequency, amplitude
SHORTER WAVELENGTH means HIGHER
FREQUENCY AND ENERGY!
Longitudinal vs. Transverse
Compression waves
where one part of a
medium smashes into
another
Wave particles travel
parallel to the energy
SOUND WAVES are
longitudinal. They
cannot travel in space
because there is no
medium
Up and down waves,
like wiggling a rope
back and forth
Wave particles travel
perpendicular (at right
angles) to the energy
being transferred
Electromagnetic waves
are transverse!
LINK TO SIMULATION
Mechanical vs. Electromagnetic
MECHANICAL WAVES:
Require a medium, or
something to travel
through (cannot travel
through space)
Water waves, waves in
a rope or slinky, and
sound waves are
examples
ELECTROMAGNETIC WAVES:
Require NO
medium, can travel
through outer
space!
ALL EM waves
travel at the
“speed of light”
3 x 108 m/s or
186,000 miles/sec
Electromagnetic waves,
from low to high frequency:
RADIO WAVES
LONG wavelength, LOW
frequency AND energy
MICROWAVES
INFRARED (HEAT)
v = f 
VISIBLE LIGHT
ULTRAVIOLET
SHORT wavelength, HIGH
X-RAYS,
frequency AND energy
GAMMA RAYS
link to applet
So for ALL electromagnetic waves…
As the FREQUENCEY gets higher, what
happens to the WAVELENGTH since the
SPEED is THE SAME for all EM radiation?
Wavelength gets SHORTER as frequency gets
higher, of course!
VISIBLE LIGHT
Only a SMALL band of the EM spectrum
Regular “white” light can be separated into all
the different colors with a prism
This was discovered by Isaac Newton!
RED (longest wavelength, lowest energy) to
VIOLET (shortest wavelength, highest energy)
ROY G BIV stands for Red, Orange, Yellow,
Green, Blue, Indigo, Violet
Electromagnetic vs Sound
ALL travel at the
“speed of light”,
186,000 miles/second
or 300,000,000 m/s
Transverse
Don’t need a medium
Can travel through
outer space, all
across the universe
Travels MANY MANY
times slower, only about
370 m/s (almost a million
times slower!)
Longitudinal
Require a medium
(mechanical)
Cannot travel through
outer space
Energy gets
dispersed(spreads out)
quickly
Doppler Effect & Red Shift
http://paws.kettering.edu/~drussell/Dem
os/doppler/doppler.html
Remember that light (and all
EM) waves are pure
ENERGY…and energy is…
The ability to “do work” or make a
CHANGE in something
Energy has many forms, and all can be
transformed from one to another
There is a CONSTANT amount of energy
in any given closed system, even in the
universe as a whole!
Induction of T-T Dimers by UV radiation
Thymidine Dimers are produced when adjacent
thymidine residues are covalently linked by
exposure to ultraviolet radiation. Covalent
linkage may result in the dimer being replicated
as a single base, which results in a frameshift
mutation.. http://www.mun.ca/biology/scarr/ThymineThymine_Dimers.html
SOLAR ANIMATION
http://www.artescapesonline.com/movies
/stirling_solar_dish_animation.htm
Breaking the sound barrier
http://hyperphysics.phyastr.gsu.edu/hbase/sound/soubar.html
http://physics.info/shock/
Energy
transferred
How is energy
transferred from the
SUN, to you walking
down the sidewalk?