Download Em Waves

197 Waves and the EM Spectrum
2/22-25/2013
3/01/2017
EQ: How can patterns be used
to describe the universe?
Waves and the EM Spectrum 198
2/22-25/2013
3/01/2017
Practice/Application:
Notes
Starter/Practice:
When looking at the night
sky, Shrek tells Donkey,
“The stars don’t tell us our
future, but our past.” Do
you agree or disagree?
Why? Please explain your
thoughts on this. Use what
you learned in your notes!!!
Connection:
WS
Exit:
Describe what you have learned
about the EM spectrum. Please
write 3-4 sentences!!
March 01, 2017
AGENDA
Objective 8.8C
Explore how different
wavelengths of the
electromagnetic spectrum
such as light and radio
waves are used to gain
information about
distances and properties
of components in the
universe by completing
notes.
1. Starter
2. Activity
3. Notes
4. Exit
Table of Contents
Date
2/28
3/1
Lecture/ Activity/ Lab
Big Bang Lab
Waves and the EM Spectrum
Page
195-196
197-198
TEKS 8.8C explore how different
wavelengths of the
electromagnetic spectrum such
as light and radio waves are
used to gain information about
distances and properties of
components of the universe
How Do
Astronomers
Gather Information
About Space?
Most of the information
we have about the
universe comes from
radiation.
Objects in the
universe,
such as stars
and galaxies,
emit
radiation.
This radiation travels
as waves. Different
kinds of radiation
have differing
wavelengths and
energies.
We cannot see most of
the radiation, but
telescopes are used to
collect the radiation
for astronomers to
study.
The entire collection of
different kinds of
radiation is called the
Electromagnetic
Spectrum.
The electromagnetic
spectrum is a continuum of
waves divided into regions
based on wavelengths.
At one end of the
spectrum are radio
waves, which allow
you to listen to your
favorite radio station.
In the central portion is
the only part of the
spectrum you can see
with your eye, the
visible region.
Most of the
visible
region
comes from
the Sun.
When light is passed
through a prism, it bends
and separates into its
different wavelengths.
Spectroscopy is
the study of
the spectrum.
A spectroscope is used to separate
light into its component
wavelengths so that they can be
studied.
The pattern of
wavelengths and colors
is called a spectrum.
By obtaining and analyzing the
spectrum from a distant object,
astronomers can determine the
object’s temperature, density,
direction of motion and
composition.
Each element
composing a star has a
unique spectrum. Just
like a fingerprint…..
Astronomers use the
spectral patterns from
stars and other
objects to determine
what elements
compose the object.
Electromagnetic Waves
EM Waves travel through
empty space and do not need
a medium in which to travel
 Examples of EM waves are:
microwaves, radio waves, xrays, and visible light.
The most important properties
are frequencies and
wavelength.
Radio Waves & Microwaves
Radio waves
 Long wavelengths; low energy.
 Radio and television stations
broadcast using radio waves.
Microwaves
 Shorter wavelengths and more energy
than radio waves.
 The waves cause water to vibrate; this
energy gives off thermal energy.
Infrared waves
Infrared Radiation (IR)
slightly lower energy than
visible light
can increase the thermal
energy of objects
Used by sensors in satellites
and planes to gather
information. Emitted by the
sun, stars, and planets
Visible Light
Visible Light
 small part of the
EM spectrum we
can see
 ROY G. BIV colors in order of
increasing energy
 Used to help
determine star’s
temperature
red
R O Y
G.
orange
green
yellow
B
blue
I
indigo
V
violet
Ultraviolet
Rays
Ultraviolet Radiation (UV)
slightly higher energy than
visible light
Types:
• UVA - tanning, wrinkles
• UVB - sunburn, cancer
• UVC - most harmful,
sterilization
X- rays
X rays
higher energy than UV;
short wavelengths
can penetrate soft
tissue, but not bones
Hot gases in the
Universe also emit Xrays .
Gamma Rays
Gamma rays
highest energy
EM radiation; shortest
wavelengths
emitted by radioactive
atoms
used to kill cancerous
cells
Radiation treatment using
radioactive cobalt-60.
197 Waves and the EM Spectrum
2/22-25/2013
3/01/2017
EQ: How can patterns be used
to describe the universe?
Waves and the EM Spectrum 198
2/22-25/2013
3/01/2017
Practice/Application:
Notes
Starter/Practice:
When looking at the night
sky, Shrek tells Donkey,
“The stars don’t tell us our
future, but our past.” Do
you agree or disagree?
Why? Please explain your
thoughts on this. Use what
you learned in your notes!!!
Connection:
WS
Exit:
Describe what you have learned
about the EM spectrum. Please
write 3-4 sentences!!