Light is made of photons
Photons carry energy
Energy = radiation
A wave of light and a ray
of light are the same
light waves are called electromagnetic waves
These waves carry energy
Parts of a Light Wave
λ = wavelength = length of
one wave measured from
crest to crest or trough to
trough
A = the height
of the wave =
brightness of
the light
f = frequency = speed of the wave or
the number of waves that pass per
second
All waves carry energy
Relationship to energy
Low frequency
High frequency
The Electromagnetic Spectrum –
describes all of the different types of
light that exist: radio, microwave,
infrared, visible, ultraviolet, x-ray,
and gamma
Which wave carries the highest amount of energy?
Which wave carries the least amount of energy?
For each part of the
spectrum you need to know
the following information:
 Size of the wavelength
 Objects that naturally produce this
type of light
 How the light interacts with
humans
Gamma Rays
The wavelength size:
(cm)
 Objects that produce gamma
rays:
 supernova explosions, neutron
stars, and black holes
 Interaction with humans - used to:
This is the size
of an
sterilize surgical instruments
kill harmful bacteria in food
kill cancer cells
Gamma Rays
Cool Info – what the sky would look like if you could
see gamma photons
(m)
http://imagine.gsfc.nasa.gov/docs/features/movies/gamm
a_rays.html (open the website and click on the purple
picture and make the video full screen)
X-Rays
The wavelength size:  Objects that produce X-rays:
 black holes, neutron stars, binary
(cm)
star systems, supernova remnants,
stars, the Sun, and even some
comets
 Interaction with humans - X-rays pass
This is
the size
of an
through skin and soft tissue, but not
through bone or metal.
 used to produce photographs of
bones to check for damage such as
fractures.
 also used in industry to check metal
for cracks or other damage.
X-rays – cool facts
 Discovered in Germany
1895 by Wilhelm
Conrad Roentgen
 He named them ` X `
rays because he did not
know where the rays
were coming from.
 His first image was of
his wife‘s hand (shown
to the left)
Ultraviolet light
The wavelength size:  Objects that produce ultraviolet
light:
 the Sun and other stars
(cm)
This is
the size
of a
 Interaction with humans
 sun beds
 security pens that airport officials
use to check passports
 fluorescent lights (phosphor
coatings inside the bulb absorb the
ultraviolet light and re-emit it as
visible light)
Ultraviolet – cool facts
harmful
 The energy from ultraviolet
radiation can damage the
molecules in your skin and
even your DNA.
 When you have a sunburn
proteins in the blood make
your blood vessels larger–
this is why your skin turns
COOL – bees, butterflies, and other red (Sobell 2001).
animals can see UV light: to them the
sky appears purple and flowers
appear different colors (see picture –
what we see and what bees see)
beneficial
 We need UV light to make
Vitamin D
 Vitamin D is important in
making strong bones, a
healthy immune system, and
in making cells.
Visible Light
The wavelength size:  Objects that produce Visible light:
 You (a very small amount), sun
and other stars, light bulbs
(cm)
 Interaction with humans –
 This is the only type of light we can
see with our eyes
This is
the size
of an
Visible Light
White light is
made of 6
different colors:
Red
Orange
Yellow
Green
Blue
Purple
Each color carries a
different amount of
energy – which color
would carry the most
energy? The least
amount of energy?
Infrared light: heat energy
The wavelength size:  Objects that produce Visible light:
 You and other animals, sun and
other stars, light bulbs
(cm)
 Interaction with humans – used in
 security lights
 burglar alarms
 remote controls for television sets and
This is
the size
of an
DVD player
 data links over short distances
between computers or mobile phones
Infrared: cool facts
This is the main light we and other animals produce –
this is the heat you feel coming off your cheeks
Microwave
The wavelength size:  Objects that produce microwave
light:
 stars
(cm)
This is
the size
of an
 Interaction with humans –
 Cooking food – the radiation vibrates
the molecules in the food to heat up
the food
 Use to learn about the weather
 Used to transfer information :
 Bluetooth
 Wifi
 Cell phones
 Microwave ovens
Microwave radiation is everywhere in
the universe it is left over radiation
from the BIG BANG
The view of the
microwave
radiation in the
universe
around us
http://www.dnatube.com/video/28547/Cosmic-MicrowaveBackground-Radiation (play video)
Radio
The wavelength size:
(cm)
 Objects that produce microwave
light:
 planets and comets, giant clouds
of gas and dust, and stars and
galaxies
 Interaction with humans – To
transfer information to and from
Radio and television stations
Wifi
Computers
Cell phones
Radio emissions from space
 Radio is a type of
light that we use to
make sound: radio
waves and changed
into sound waves
(see illustration
below)
Radio signals from stars, pulsars, black
holes and other objects in space
produce radio waves. We change these
signals into sound waves that we can
hear.
 http://www.spacesounds.com/home
/index.html (click on this link and
then click on 2-3 different sources)
Questions for objective 3
 Describe what all of the waves have in
common.
 Describe the 3 main differences
between the waves.
Finish Questions from
objective 2 (oage 11)
Video
 If there is time watch the video:
 http://www.youtube.com/watch?v=HPcAWNl
Vl-8
Sources
 "Gamma Rays." - Mission:Science. NASA, n.d. Web. 07 Oct. 2012.







<http://missionscience.nasa.gov/ems/12_gammarays.html>.
Nelson, Brent. Ask the Experts. Physicslink.com, n.d. Web. 7 Oct. 2012.
<http://www.physlink.com/education/askexperts/ae636.cfm>.
Plait, Phil. "Bananas | Bad Astronomy | Discover Magazine." Bananas | Bad
Astronomy | Discover Magazine. N.p., 21 Mar. 2011. Web. 07 Oct. 2012.
<http://blogs.discovermagazine.com/badastronomy/tag/bananas/>.
Sobell, Jeffrey M. "What Happens When You Get a Sunburn?: Scientific
American." What Happens When You Get a Sunburn?: Scientific American.
Scientific American, 6 Aug. 2001. Web. 07 Oct. 2012.
<http://www.scientificamerican.com/article.cfm?id=what-happens-when-youget>.
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/radiation/the_
electromagnetic_spectrumrev4.shtml
http://www.youtube.com/watch?v=HPcAWNlVl-8
http://www.youtube.com/watch?v=m4t7gTmBK3g
http://education-portal.com/academy/lesson/the-7-major-regions-of-theelectromagnetic-spectrum.html#lesson (login)
More space sounds
 http://www-pw.physics.uiowa.edu/space-audio/
 http://www.spaceweather.com/glossary/inspire.html