ELECTROMAGNETIC WAVES &
THE ELECTROMAGNETIC SPECTRUM
SPECTRUM
• The pattern light produces when passed through a
prism or spectrograph
• Prism – 3 dimensional object that refracts light.
• Spectrograph – device that allows us to see the
spectrum
Visible Light
Remembering the Order
ROY G. BIV
red
orange
yellow
green
blue
indigo
violet
ELECTROMAGNETIC WAVES
• Transverse
• Electric and Magnetic
• Can travel through empty space
(able
• Wavelength the length of one
wave
• Frequency how often something
happens
• With waves, it's "how many
waves per second“
• Brainpop; WAVES
• Electromagnetic waves travel
VERY FAST – around 300,000
kilometres per second (the speed
of light).
All electromagnetic
waves travel at the same
speed. (300,000,000
meters/second) in a
vacuum.
At this speed they can go
around the world 8 times
in one second.
ELECTROMAGNETIC SPECTRUM
• They all have
different
wavelengths and
different
frequencies.
• Long wavelengthlowest
frequency
• Short
wavelength
highest frequency
• The higher the
frequency the
higher the energy.
• Brainpop:
Electromagnetic
Spectrum
Longer
Wavelength
Less energy
Lower
frequency
Shorter
Wavelength
More energy
Higher
frequency
ROY G BIV
Cook
Nuclear
Power
Healthcare
Sunlight
Sanitize
Communicate
Heat
Remote
control
SPECTRAL ANALYSIS LAB
Stars – Spectral Analysis
Purpose: To determine the composition of stars using a
spectral analyzer.
Background:
1. A spectrum photograph can be sorted across a plate to
reveal spectral lines.
2. Lines represent the chemical composition of the star so
each star has its own fingerprint.
Procedure:
1. Examine each star (A, B, C, D) for chemical composition
2. If lines match, the element is present.
3. Check the box if the element is present.
ON BACK OF LAB SHEET:
TALLY # OF LINES FOR EACH COLOR
Star
A
Indigo
Blue
Green
Yellow
Red
B
C
D
Answer this question on the back:
Why do astronomers need to know
what elements are in stars?
Turn in lab sheet 
STUDENT HANDOUTS