10/06 (p. 30) EM Spectrum/Light
Notes
• IQ: Complete anticipation guide for EM
waves.
Glue/tape
• Unit title page on 29-30 (skip p. 28)
• Yellow anticipation guide half sheet on
p.30
• Blue EM spectrum half sheet on p. 31
K-12 Science, CCSD, 2006
Electromagnetic Spectrum:
• The full range of frequencies, from radio
waves to gamma waves, that
characterizes light.
• All EM waves travel at the same speed
through space, only their frequency/energy
is different.
• EM waves are emitted by charged
particles in atoms when heat or electrical
energy is added.
K-12 Science, CCSD, 2006
The light we see is part of a spectrum- EM
spectrum.
All are transverse, and can travel through space.
Increasing freq. and energy
Decreasing wavelength
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K-12 Science, CCSD, 2006
• EM waves have an electric and a
magnetic component vibrating at a 90
degree angle with each other.
• Radiation- energy that can travel through
space and matter without using the matter.
K-12 Science, CCSD, 2006
• OQ: What are two main differences, and
one similarity between light and sound
waves?
K-12 Science, CCSD, 2006
10/7 p. 32 Electromagnetic
Spectrum Foldable
• Which property distinguishes between the
different types of EM Waves?
K-12 Science, CCSD, 2006
EM Spectrum-Relative
Wavelengths Video
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The sun gives off all 7 types of
EM Waves.
• http://video.pbs.org/video/2219781967/
K-12 Science, CCSD, 2006
1. Radio waves
 Longest
wavelength, lowest energy
EM waves
 Uses:





TV broadcasting
AM and FM broadcast radio
Avalanche beacons
Heart rate monitors
Cell phone communication
2. Microwaves
 Wavelengths
from 1 mm- 1 m
 Uses:





Microwave ovens
Bluetooth headsets
Broadband Wireless Internet
Radar
GPS
3. Infrared Radiation
 Wavelengths
in between microwaves
and visible light
 Heat waves
 Means below red.
 Uses:




Night vision goggles
Remote controls
Heat lamps
Heat-seeking missiles
4. Visible/white light
 Only
type of EM wave able to be
detected by the human eye.
 Contains all 7 colors.
 Violet is the highest frequency light
 Red light is the lowest frequency
light.
 Uses:Lighting, photosynthesis
5. Ultraviolet (Video)
 Shorter
wavelengths than visible light
 Means above violet.
 Uses:




Black lights
Sterilizing medical equipment
Water disinfection
Security images on money
6. X-rays
Tiny wavelength, high energy waves, can
penetrate skin and soft tissue but not bones.
X ray images are shadows not the actual
x rays.

 Uses:



Medical imaging
Airport security
Inspecting industrial welds
7. Gamma Rays
 Smallest
wavelengths, highest
energy EM waves
 Uses



Food irradiation
Cancer treatment
Treating wood flooring
OQ: True or False:
Gamma rays travel much faster than radio
waves.
K-12 Science, CCSD, 2006
Go back to Anticipation guide on p. 44 and
mark T or F for each statement on the right.
K-12 Science, CCSD, 2006
• NASA EM Spectrum videos
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10/09 (p. 48) Tour of the EM
spectrum
IQ: Pick all that apply for EM waves:
a. Do not need a medium.
b. We can see only about half of them.
c. All travel at different speeds.
d. All have different amounts of energy.
e. All have the same wavelength.
K-12 Science, CCSD, 2006
OQ: Which of the following will be the
hottest? Explain.
a. A red star
b. A yellow star
c. A blue star
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10/13 Visible Light Notes
IQ: An object appears to be green because
it ___________ (reflects, absorbs, refracts)
the green part of the visible spectrum.
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Visible light
• Visible or white light (the only part we can
see) is a narrow band in the middle of the
EM spectrum, and contains the seven
colors that we see in a rainbow.
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•
Light
Waves
Light is produced when
vibrating electrons release
energy as particles called
photons.
• Light travels in transverse
waves.
• Light waves do not need a
medium. They can travel
through nothing-- space or
vacuum!
• Study jams
•K-12Fluorescence
Science, CCSD, 2006
Parts of a Wave
D = one full wave
= one wavelength
= one period
D
A
C
A = Crest
B
B = Trough
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C = Amplitude
Light Properties
1. In visible light
waves, the amplitude
of the waves
determines the
brightness.
2. The
frequency/wavelength
determines the color.
All 7 colors of light
show
up
as
white
light.
K-12 Science, CCSD, 2006
• What color would you see if you mixed the
seven colors in case of paint?
K-12 Science, CCSD, 2006
Watch and discuss
• http://phys.org/news200044818.html
• Turn to your partner and discuss in
about 10s, what is going on in the
animation and why.
• The Doppler effect of light. Star’s color
changes as it goes away and comes
closer.
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Light Wavelengths
• Light has different wavelengths.
Red light has a large wavelength.
Blue light has a shorter wavelength.
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Light Wavelengths
• Which wave has higher energy?
Red light has a large wavelength.
Blue light has a shorter wavelength.
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Frequency
Red light has a large wavelength.
Blue light has a shorter wavelength.
• More of the shorter blue waves can pass
through a point at a time so they have a
higher frequency and energy.
K-12 Science, CCSD, 2006
Frequency – Visible Light
Red light
Orange light
Yellow light
Green light
Blue light
Violet light
K-12 Science, CCSD, 2006
Frequency – Visible Light
Red light
Orange light
Yellow light
Green light
Blue light
Violet light
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Frequency – Visible Light
The light we use to see has all of these
wavelengths in it. Blue light has the
shortest wavelength, highest frequency,
red has longest wavelength, longest
frequency.
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So . . . How Do We See Colors?
Let’s start with our eyes.
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So . . . How Do We See Colors?
If there is light . . .
K-12 Science, CCSD, 2006
So . . . How Do We See Colors?
If there is no light . . .
K-12 Science, CCSD, 2006
So . . . How Do We See Colors?
If there is no light . . .
you cannot see
because there are no
light waves reflecting to
your eye.
Our eyes only see light
K-12 Science, CCSD, 2006 reflected off things!
So . . . How Do We See Colors?
The green part absorbs all of the colors
except green. It reflects green light.
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The red part absorbs
all of the colors
except red. It
reflects red light.
• Brainpop Color
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3. The speed of light is
affected by the density of
the medium. It travels
fastest through vacuum,
slower through air/gases,
even slower through liquids,
and slowest through solids.
All colors of light travel at
the same speed through a
medium. In space, 3 x 108
m/s.
K-12 Science, CCSD, 2006
Visible light
• Visible or _______ light (the only part we can
see) is a ________ band in the ________ of the
EM spectrum, and contains the seven colors
that we see in a rainbow.
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Light Waves
• Light is produced when
vibrating electrons release
_________ as particles called
______________.
• Light travels in ___________
waves.
• Light waves _____ ____ need
a medium. They can travel
through nothing-- ________ or
vacuum!
K-12 Science, CCSD, 2006
Light Properties
1. In visible light waves,
the _______of the waves
determines the brightness.
2. The
_________/wavelength
determines the color.
Red= lowest f, Violet =
highest f
All 7 colors of light show up
as white light.
K-12 Science, CCSD, 2006
Light Wavelengths
• Light has different ____________.
_______ light has a large wavelength.
________ light has a shorter wavelength.
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Light Wavelengths
• Which wave has higher energy?
Red light has a large wavelength.
Blue light has a shorter wavelength.
K-12 Science, CCSD, 2006
Frequency – Visible Light
Red light
Orange light
Yellow light
Green light
Blue light
Violet light
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Frequency – Visible Light
The light we use to see has all of these
wavelengths in it. Blue light has the
shortest wavelength, highest frequency,
red has longest wavelength, longest
frequency.
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So . . . How Do We See Colors?
If there is _________. .
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So . . . How Do We See Colors?
If there is no light . . .
K-12 Science, CCSD, 2006
So . . . How Do We See Colors?
If there is no light . . .
you cannot see because
there are no light waves
reflecting to your eye.
Our eyes only see light
__________ off things!
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The green part absorbs all of the colors
except green. It reflects _________ light.
K-12 Science, CCSD, 2006
The _____ part
absorbs all of the
colors except red. It
__________ red light.
3. The ________ of light is
affected by the ________ of
the medium. It travels
fastest through __________
slower through air/gases,
even slower through liquids,
and ________ through
solids.
All ______ of light travel at
the _______ speed through
a medium. In space, ___x
108 m/s.
K-12 Science, CCSD, 2006
OQ: What three things are required for us to
be able to see an object?
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Light particles are called photons
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10/18 Rainbow lab
OQ: Based on what you learned about how we
see color, explain why we see the color purple
in test tube F.
K-12 Science, CCSD, 2006
10/14
Light phenomena notes
IQ: Picture someone playing a guitar.
Describe how the process of being able to
see the guitar is different from the process of
hearing it. You may draw diagrams to
explain.
K-12 Science, CCSD, 2006
On p. 53
Using your notes sheet, list
The three light phenomena with diagrams
1.__________________
2. __________________
3. __________________
4.
5.
The three types of materials with examples, depending
on how light behaves when it reaches them:
___________________
___________________
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Science, CCSD, 2006
___________________
When light waves hit a new medium they
can be
1. Reflected or bounced
back. Ex. A mirror.
• The smoother the surface,
the better the reflection.
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• We see things because they reflect light
into our eyes. The color we see is the
color of light that is reflected, rest is
absorbed.
Homework
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2. Absorbed by a material
and converted into heat.
We don’t see the color that
is absorbed by an object.
Ex. Blue object absorbs all
other colors except blue.
Reflection Absorption
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Transmission of light
3. Transmitted, passed through a
transparent substance.
• The color that is transmitted is
the color that reaches your eye.
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Reflection and absorption of light: 3
types of materials
A. Transparent transmit all light. Ex. clear
glass, plastic, air, pure water.
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Absorption of light
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B. Translucent objects transmit some light
and absorb or scatter the rest. We can
somewhat see through them but not
completely. Ex. milk, wax paper.
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C. Opaque objects reflect and absorb light.
Cannot see through them, form a shadow.
Ex. Dark curtains.
• White objects reflect all light colors.
• Black objects absorb all light colors.
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Opaque objects reflect and
absorb light
• This apple reflects red and
absorbs all other colors.
Turn to your partner and
discuss:
• What would you see if only
green light is shone on a
red apple?
• How about if the green light
is shone on a green apple?
K-12 Science, CCSD, 2006
Transparent objects transmit
color
• Red glass absorbs all colors of light
except red, which it transmits.
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• Optical illusions
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OQ: Most materials around us are
__________ which means they _______
and/or __________ the light shining on
them.
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10/16
Rainbow lab
IQ: Explain based on phenomena of light
why the blue liquid appears to be blue.
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OQ: How much liquid did you start with?
How do you get this info?
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OQ: Which of the following shows the
materials by increasing temp. if white light
is shining on them?
a. Clear colorless cup, clear gray cup,
opaque red cup.
b. Clear gray cup, clear colorless cup,
opaque red cup.
c. Opaque red cup, clear gray cup, clear
colorless cup.
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10/15 p. 54 Light Phenomena
Cont’d
IQ: Complete both sides of pink half sheet.
K-12 Science, CCSD, 2006
When light hits a new
medium it can be
4. Refracted or bent
because its speed changes
as it goes from one medium
(density) to another medium
. Ex. a rainbow where the
raindrops act like prisms.
Phet anim.
Discovery (2nd vid.)
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Diffraction
5. Light can be diffracted or
bent around a corner or
through a slit in a barrier.
Ex. light coming in through
blinds.
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When light waves hit a new medium they
can be
1. ___________ or bounced
back. Ex. A mirror.
• The _________ the surface,
the better the reflection.
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• We _____ things because they reflect
light into our ________. The color we
see is the _______ of light that is
_______, rest is absorbed.
Homework
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2. __________ by a
material and converted into
______. We _____
______ the color that is
absorbed by an object. Ex.
Blue object absorbs all
other colors ______ blue.
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Transmission of light
3. ___________, passed through a
____________ substance.
• The _______ that is transmitted is
the color that reaches your _____.
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Reflection and absorption of light: 3
types of materials
A. __________ transmit all light. Ex. clear
_____, plastic, air, pure _______.
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Absorption of light: Which colors
are being absorbed?
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B. _____________ objects transmit ______
light and ________ or ______ the rest. We
can _________ _____ through them but not
completely. Ex. milk, _____ ________.
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C. __________ objects ______ and ______
light, transmit none. ________ ____ through
them, form a shadow.
Ex. Dark curtains.
• _______ objects ______ all light colors.
• Black objects ________ all light colors.
K-12 Science, CCSD, 2006
Opaque objects reflect and
absorb light
• This apple reflects red and
absorbs all other colors.
Turn to your partner and
discuss:
• What would you see if only
green light is shone on a
red apple?
• How about if the green light
is shone on a green apple?
K-12 Science, CCSD, 2006
Refraction
When light hits a new
medium it can be
4. Refracted or _______
because its ______
changes as it goes from one
medium (density) to another
medium . Ex. a ______
where the raindrops act like
prisms.
K-12 Science, CCSD, 2006
Diffraction
5. Light can be diffracted or
bent _______ a ________ or
through a ___ in a barrier.
Ex. light coming in through
blinds.
K-12 Science, CCSD, 2006
10/20 p. 58 Light Phenomena
Rvw.
• Refraction or diffraction?
- Light bends as it goes around a barrier
- Light bends as it enters air from glass.
- A spoon looks crooked under water.
- The sun’s light spreads over the
mountain as it comes up.
K-12 Science, CCSD, 2006
Which light phenomena are taking place in
each picture?
a.
c.
b.
d.
K-12 Science, CCSD, 2006
e.
Which light phenomena are taking place in
each picture?
a.
c.
b.
d.
K-12 Science, CCSD, 2006
e.
IQ: Identify all types of materials present in
the pic. (opaque, transparent, or
translucent). Explain what happens to the
light through each.
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Bye-bye!
K-12 Science, CCSD, 2006