Have the teacher pass out the Rainbow Peephole
Theme Packets, but ask the students not to open them yet. When everyone
has their own packet, proceed as follows:
the flashlight and the peephole from your packet, hold them
up, and identify them. Ask the students to remove theirs and
figure out what to do by referring to the image of the young
lady on the back of the packet.
the oohs and ahs, ask the group, Where
does the color come from? [Many
children will answer that the colors comes from the peephole.
Tell them that the colors come from the white light in the flashlight.]
can ask any or all of the following questions:
you see a regular pattern? Describe it.
all of the colors. Are they the same in each spot?
the pattern change if the flashlight is close or far from
the peephole? How?
Do you see colors from other people's flashlights, even those
far away from you?
you see colors from the room lights?
up the packet and show the picture on the front. Describe this
as a highly magnified photograph of the surface of one side of
the clear plastic in the peephole. It is taken with an instrument
called an atomic force microscope. [Optical
engineers develop instruments like this.]
Note that the scale is in microns, that a human hair is 30 to
80 microns wide, and that the plastic has a regular array of small
bumps across it that are only two microns high - too small to
be seen or felt.
bumps are packed so closely together that about fifty of them
could fit inside a human hair. These bumps are responsible for
redirecting the light coming into the peephole, depending on its
color. Point out the similarity between the regular array of bumps
and the pattern seen through the peephole.
for a show of hands by everyone who wants a cell phone. With the
transparency (Figure 5) explain how tele-communications uses fibers
and lasers to divide light from one beam into many, each with
a different color. This is the key to unlimited numbers of conversations
all over the world at the same time. [Optical
engineers do this stuff.]
everyone to seal the flashlights and peepholes back into the packets.
Tell them the packets are theirs to keep. Suggest that they can
reveal to family members the secret of seeing colors in white
light through diffraction.
by Stephen D. Jacobs, Rebecca L. Coppens and Christine Andrews-Angelo
December 24, 2001
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