Official Documentation of Investigation
Completed By _____________________________
(Student Name)
Pre-Read
Electromagnetic versus Mechanical Waves. Another way to categorize waves is on
the basis of their ability or inability to transmit energy through a vacuum (i.e., empty
space). Categorizing waves on this basis leads to two notable categories:
electromagnetic waves and mechanical waves.
An electromagnetic wave is a wave that is capable of transmitting its energy through
a vacuum (i.e., empty space). Electromagnetic waves are produced by the vibration of
charged particles. Electromagnetic waves that are produced on the sun subsequently
travel to Earth through the vacuum of outer space. Were it not for the ability of
electromagnetic waves to travel to through a vacuum, there would undoubtedly be no
life on Earth. All light waves are examples of electromagnetic waves.
Firework Glasses: What to Do: Your job is to investigate the visible light spectrum in
order to answer the question “What color is the sun?” You will investigate the visible
light spectrum through several activities and document your findings and level of
understanding below. You can work by yourself or in groups of up to 4. Each student is
responsible for completing their own investigation document.
Engage
What color is the sun?
Imagine you are at the beach on a clear sunny day. Describe the sun? What color does
it appear? How does it feel?
Now imagine you dive underwater and are swimming with the underwater sea
creatures. You look up and can see the sun shining through? How would you describe
the color and intensity of the sun now?
Explore Wave Behaviors/Plan
Previously you learned waves (specifically sound waves)
need a medium to travel through. Now that you have been
introduced to light waves, which mostly originate from the
sun. You know that space is called “space” because there is
nothing but SPACE between celestial objects, such and the
sun and planets. The absence of matter is called a vacuum.
What happens to a light wave when it encounters the boundary between nothing
(outer space) and something else (like our atmosphere)? What happens to light
when it hits our windows?
The wave doesn't just stop when it reaches the end of a medium. A wave will
undergo certain changes in behaviors when it encounters the end of the medium,
or the start of a new one. You have learned about this already. Specifically, there
can be some reflection off the boundary and some transmission into the new
medium. What types of behaviors can be observed when light waves are passed
through different mediums?
Each student or group of students a will receive a refracting device. You will have 10
minutes to test the device and document your findings. You may shine light through it
with a flashlight or use the sunlight entering through a window. Your job is to identify
the functionality of the device (what does it do) in order to investigate the visible
spectrum.
Draw the light that entered
the device below:
Draw the refracting device
below:
Draw the light that exited
the device below:
Describe the light that
entered the device below.
What was the light source?
What color was it?
Describe the refracting
device below. What was its
color? What was its shape?
What material was it made
of?
Describe the light that
exited the light source
below. What color was it?
What pattern did you
notice?
Explain Wave Behaviors/Model Drawing
Each color is characteristic of a distinct wavelength; and
different wavelengths of light waves will bend varying
amounts upon passage through a prism. For these reasons,
visible light is dispersed upon passage through a prism.
Dispersion of visible light produces the colors red (R), orange
(O), yellow (Y), green (G), blue (B), and violet (V). It is
because of this that visible light is sometimes referred to as ROY G. BIV.
(Incidentally, the indigo is not actually observed in the spectrum but is
traditionally added to the list so that there is a vowel in Roy's last name.) The red
wavelengths of light are the longer wavelengths and the violet wavelengths of
light are the shorter wavelengths. Between red and violet, there is a continuous
range or spectrum of wavelengths. The visible light spectrum is shown in the
diagram below.
Go to: https://phet.colorado.edu/sims/html/bending-light/latest/bending-light_en.html
Click on PRISMS
Configure
settings as shown
Scenario
What happens to the light
as it encounters the
surface of the prism?
Rotate the refracting
device (prism) until you
get a rainbow, draw
orientation (positioning) of
the light source and prim
that produces a rainbow.
An incident ray shines on a
triangular prism.
An incident ray shines on a 4sided regular polygon
(square).
An incident ray shines on a 4sided irregular polygon.
An incident ray shines on a
round prism.
Finally: change your setting to
the laser beam. Are you able to
make a rainbow with a laser beam? Which prism did you use? What color light did you
use?
Elaborate on Color Vision!
Diffraction glasses allow you to see the world in a whole new way. You can
have a lot of fun with them watching fireworks, and looking at various other
light sources, whether artificial or natural. They're also great for parties.
Just hand them out and let people discover for themselves the visual treat
that they provide.
When you look through these glasses you are looking through a special
material called a diffraction grating. This grating is a piece of plastic that has many slit-like
openings that are very narrow and closely spaced to each other. When light passes through these
openings, it bends by an amount dependent on the type of light. For example, red light bends
more than yellow light.
While wearing the Firework Glasses, focus on a light and dark
colored object and record your observations.
Light Colored Object
Dark Colored Object
What is the object?
What is the object?
What did you see?
What did you see?
What pattern did you observe? You may illustrate your
observations.
Did the light color or dark colored object produce a better
effect? What is your explanation for this phenomena, using
the words REFLECT and ABSORB?
Evaluate
PhET Color Vision
Step 1:
Questions
Based on
Step 1:
a. Go to the following: https://phet.colorado.edu/sims/html/colorvision/latest/color-vision_en.html and click Single Bulb.
b. Turn the flashlight ON by clicking the red button on the flashlight.
c. You should see a yellow light coming from the flashlight.
d. Click the particle view of light by selecting this option
1. What color particles are being emitted from the flashlight when the
yellow bulb is selected? _________________
2. What color does the brain see? (depicted by the thought bubble above
the observer’s head) ________________
Step 2.
Questions
Based on
Step 2:
a. Now, JUST ABOVE the flashlight, hit the option to use the white
colored bulb instead of the yellow light on the left.
1. What colors do you see actually make up white light?
____________ ____________ ____________ ____________
____________ ____________ ____________
2. What is the abbreviation for these colors? ________________
3. What color does the brain still see? ________________
Step 3.
a. Turn ON the filter color option by clicking on the black circular switch
down and to the left of the flashlight. If you do this correctly, you should
see the yellow filter appear.
Questions
Based on
Step 3:
1. What color is able to pass through the YELLOW filter? ______________
2. Which colors are being absorbed by the filter? _________________
_________________ _________________ _________________
_________________ _________________
Essay Response
Refer to
Burning Text with Light and Color and The Electromagnetic Spectrum to address the following
prompt:
According to ancient writings, the great scientist and mathematician Archimedes (287 – 212
BCE) supposedly used mirrors to burn Roman ships during the Siege of Syracuse (212
BCE). In the 12th century, historians Tzetzes and Zonares quoted an ancient lost book,
Siege of Syracuse:
“When Marcellus [The Roman General] had placed the ships a bow shot off, the old man
[Archimedes] constructed a sort of hexagonal mirror. He placed at proper distances from
the mirror other smaller mirrors of the same kind, which were moved by means of their
hinges and certain plates of metal. He placed it amid the rays of the sun at noon, both in
summer and winter. The rays being reflected by this, a frightful fiery kindling was excited on
the ships, and it reduced them to ashes, from the distance of a bow shot. Thus the old man
baffled Marcellus by means of his inventions.”
Part 1
Refer to Burning Text with Light: Explain the principles of design for how this invention (page 1)
supposedly worked. Explain the attempt to replicate its functionality (page 5). What are
limitations of this attempt at replication? What could be done differently? What evidence
suggests the weapon is a myth? What evidence suggests the weapon is plausible? Response
must address: mirror functionality, color of mirror, color of reflected light.
Part 2
Refer to Color and The Electromagnetic Spectrum: (page 2-3) How are water droplets and
prisms similar and different? Explain a situation, such as high humidity, where it might be
possible to accidentally use this weapon to produce rainbows. Explain how this phenomena
would occur and the anticipated/predicted effects if it occurred during a battle. Response must
address: color of the sun, components of visible spectrum, behavior of light as encounters a
new medium, understanding of prism functionality and ability to make connection to water
droplets.
Outline: