THE FACTS OF LIGHT
In this lesson and the use of its extending activities, the
students should better understand light and its capabilities. Through the
viewing of the recommended tapes and the hands-on activities of the guided
experiments, they should have a better understanding that light is a wave
that goes in a straight line unless it bumps into something. Should this
happen, light can then either bend, bounce or be absorbed. This lesson would
also be a good extension to the teaching of the five senses with the eye
explicitly in mind and a further exploration into the colors of light and
how we see them. This lesson also goes quite strongly with math concepts
relating to finding patterns, multiples, filling in charts, and expressing
information in the form of ratios, although this would take additional time
should children not already have a background in ratios.
Bill Nye The Science Guy: Light Optics (KCTS/Seattle)
A Journey Through Your Eyes (cc) (American Optometric Association)
This video and curriculum guide may be obtained free of charge through
American Optometric Association
243 North Lindbergh Blvd.
St Louis, MO 63141
Students will be able to:
- describe what three things can happen to light when it hits something;
- have a better understanding of how a kaleidoscope works;
- be able to measure distances from one image to an object;
- use a protractor to measure the angle of the hinged mirror and identify
patterns with their relationship between the number of degrees and the number
of images (angles that are proportional or multiples of each other).
"Find the Rainbow Colors"experiment
"Bend Light With Water" (One supply for the class)
- a shallow bowl or pan
- one sheet of silver plastic
- a white wall or cardboard
- a flashlight
- white paper
- a prism
"The Coin Illusion" (one supply for each group of four to six)
- a clear drinking glass
- a pencil
"Checking All The Angles" (per group of two-four students)
- an opaque (not clear) bowl
- transparent tape
- a coin
"Make a Kaleidoscope"
- a book
- a sheet of white paper
- a comb
- a flashlight
- a darkened room
- one sheet of silver plastic
- a friend or helper
- a pencil or pen
- a ruler
- a protractor
- 3 sheets 1"-by-4" card stock backed with silver mylar
- transparent tape
- 3/4 ounce plastic portion cup
- brightly colored clear plastic beads
- toilet paper tube
- 2 pieces of paper towel
light - electromagnetic radiation that can be seen by the naked eye
light spectrum - a name given to the rainbow colors found in white
reflection - bouncing back of a light beam or a sound wave
refraction - the bending of a light ray that occurs when it passes
through certain substances
internal reflection - reflection inside something
focal point - the point where light rays intersect
concave - hollow and curved inward (like a cave)
convex - curved outward like the outer surface of a ball
Start by talking about light itself. What is light? White light
that comes from the sun and from ordinary light bulbs is called white light.
But did you know that white light really isn't white? White light is a mixture
of every color of the rainbow. The children should be able to recall what
the colors of the rainbow are but if not sure of the order, tell them to
try to remember the name Roy G. Biv. This name comes from the first letter
of each color of the rainbow: Red, Orange, Yellow, Green, Blue, Indigo,
Prove this by doing the experiment "Find the Rainbow Colors."
Fill the bowl or pan with water. Put it in a sunny sport of near a source
of bright light such as a lamp, sunny window or flashlight. Hold the silver
plastic in the water so that it faces the light source. The white wall or
cardboard should be opposite the silver plastic. Adjust the silver plastic
until you can see a colorful spot on the wall or cardboard. You will see
tiny bands of colors: red, orange, yellow, green, blue, indigo and violet.
These colors are called the rainbow or light spectrum. Explain that the
water bends each color of light differently so when the light reaches the
white wall, it is no longer mixed into white light. It is separated into
different colored bands.
Emphasize this by letting the sun or flashlight beam shine directly through
the largest side of a prism onto the white paper. Adjust the prism by tipping
it up and down a bit. When the prism is at the right angle, you will see
the rainbow or light spectrum on your paper. Ask if these colors came as
the ones you saw in the first activity? Are they in the same order? Did
they see Roy G. Biv?
To give the students a specific responsibility while viewing
say, "You are now going to view Bill Nye The Science Guy: Light Optics.
You will be able to take the information you just learned about the eye
and 'Roy G. Biv' and combine it with additional information on light and
how it travels, what changes the way it travels, and how we can change light's
beam at times. After watching this part of the video we will be learning
about how the eye works and how it relates to light. We will also be working
with mirrors and discovering what makes the images change."
Note to the Teacher: This lesson can easily be broken into two or even three
parts. The first is the basics of light, the second would be the eye itself
and how it works, and the third could be refraction, reflection and mirrors
with their activities.
START the video Bill Nye The Science Guy: Light Optics
after the credits to where the two men introduce themselves saying, "Hi,
I'm Penn and this is Teller..." PAUSE the video and discuss
what was meant by using the names "Penn" and "Teller."
RESUME the video and continue until after the second light bulb where
the girl says, "light travels in a straight line unless it hits something
or is pulled by gravity." PAUSE and review what happens to light
when it runs into something. Tell the children that they will now see examples
of reflection and learn what a focal point is. RESUME the tape at
the two words "reflection" and "refraction". They will
watch examples of large dishes used for outer space and discover how remote
controls work for televisions. PAUSE where both children are arguing
over the remote control, saying, "channel 9, channel 11." Discuss
the difference between the white paper and the black paper. Why doesn't
the black paper work? RESUME at the word "refraction,"
where Bill Nye says, "This magnifying glass is making my eye big. Why
is that?" Continue until they are showing light going through a curved
lens and the word "focal point" appears. STOP the video.
Discuss what happens to light as it passes through something clear like
plastic. Ask them if they could think of anything else that light might
be able to pass through? Ask them what the round plastic reminds them of.
Wait or encourage the idea of eye glasses.
Note to teacher: This is a good stopping point if the lesson is too long
for a class period.
Now tell the children that this lesson will be investigating how the eye
works and how it is related to light. Tell them that they will be watching
another video on the human eye.
START the video A Journey Through Your Eyes at the beginning. PAUSE
where the narrator is saying, "this entire process is called vision."
There is a profile of an eye with an airplane image. Go over the eye model
and review the parts of the eye. Resume where the narrator is saying, "Now
that you understand how vision works, let's look at some things that can
be problems to the eye." Watch as they discuss farsightedness, nearsightedness
and astigmatism. STOP after the study of astigmatism where there
are colorful flowers and the narrator is saying "this will allow you
to see clearly at all distances." Have a discussion and review of the
different parts of the eye, the three major problems of the eye and how
certain kinds of lenses can correct these problems by the way that light
goes through the lens.
Go back to the video Bill Nye The Science Guy: Light Optics . Review what
a focal point is and readdress the question of why Bill Nye's eye was larger
when holding the magnifying glass up to his eye. REWIND to the words
"Refraction and Reflection," just after the two children are arguing
over the television channels. Bill Nye is saying, "This magnifying
glass is making my eye look big. Why is that?" Now say to the children,
"Now that you have a better understanding of how the eye works, I would
like to show you the segment about the magnifying glass again. This time
I would like you to think about why your eye looks large when it is seen
through a magnifying glass." RESUME the video to review the
different things light can do. STOP at the end of the segment before
Reinforce the information shown in the tape by doing the three
experiments that represent light bouncing, bending and reflect. As you finish
each one, discuss how each experiment demonstrates what light is doing.
Once this is done, talk about how light is absorbed, for example, with black
paper or the greenhouse.
Bouncing Light: When you bounce a ball straight down, it travels straight
up again. But if you bounce a ball away from you, it hits the ground at
an angle. It bounces away from the ground at the same angle. Light can also
bounce from a surface at an angle.
Find out about the Angle of Light reflection with the following experiment.
Checking All the Angles: Place the white paper over the book. Hold the comb
so that the teeth raise above the edge of the book. Darken the room and
turn on the flashlight. Direct the light at the comb and book. Tilt the
book so that long rays of light can be seen on the surface of the paper.
Now hold the silver plastic upright on the paper. You will see reflected
bars of light crossing the original bars.
Keeping the silver plastic upright, move it so that the bars of light hit
it at different angles. What happens to the reflected bars of light? What
patterns can you make with these bars of light? Use a ruler to draw a diagonal
line across the white paper. Hold the silver plastic up to the line. Have
a helper trace on the bar of light coming from the flashlight. Then have
the helper trace the same bar of light as it reflects off the silver plastic.
Turn on the lights and look at the paper. Look at the angles made by the
bars of light and the silver plastic. Is the angle made by the bar of light
coming from the flashlight the same as the angle made by the reflected bar?
You may want to use a protractor to be sure.
Bend Light With Water: Normally light travels in straight lines. It does
not turn corners. But now you will discover that light does bend sometimes,
after all! Put the pencil in a glass of water so that it is at a slant.
Look at the pencil through the top of the glass. Does it bend? Why do you
suppose it looks this way? Look at the pencil through the side of the glass.
How does it look? (internal refraction) Now hold the pencil straight up
and down in the water. Again look at it through the top and side of the
glass. Does the pencil look bent? Try the same experiment with a drinking
straw or butter knife.
Coin Illusion: Tape a coin to the bottom of a bowl. Now sit so that the
coin is just out of your view behind the rim of the bowl. Sit very still
while another person slowly pours water into the bowl. Does the coin reappear?
Note to the teacher: Without any water in the bowl, the light that reflects
off the coin travels in a straight line, missing your eyes. However, when
water is in the bowl, the light refracts, or changes direction. When the
light changes direction you can see the coin.
Have an optometrist come to visit the class and explain about the different
kinds of eye disorders, the different lenses used to correct them, and the
major eye diseases and injuries to the eye.
Have an optomologist come to the class to talk about the new surgery that
can be done on people's eyes that will change the shape of their eye and
therefore correct their vision.
Invite other surgeons to come to the class to talk about all the micro surgeries
performed today and how exactly they are performed. It might also be possible
to go to a local hospital and see the equipment directly.
Visit a green house and talk about how it functions effectively.
Math: Do additional work with protractors and taking accurate
measurements of different sized angles under 180 degrees. Practice enough
so that children can recognize obtuse from acute and can also recognize
a 90 degree angle.
Science and Math: Do an activity placing a folding mirror on previously
drawn lines that are at specific sized angles. Then hold an object or picture
in front of folding mirrors. Predict how many images can be seen all together
at the different set angles. Then actually count.
Social Studies and Writing: Have the students look up Albert Einstein to
find out more about what his part in history was. Write a report to present
to the class on your findings.
Art and Science: Make a periscope by using mirrors and a quart-size milk
or juice container.
End your entire unit on light by having the children make a kaleidoscope
to take home. It is a great keepsake and a reminder of light and how they
see all that they see. (See attached instruction sheet.)
Master Teacher: Gail Roberts
Lesson Plan Database
Thirteen Ed Online