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Materials:
white paper; white crayon; pink, green or blue highlighter (yellow
doesn't work as well).
Procedure:
write a "secret message" on the white paper using the
white crayon. To reveal the message, color over the message
area with the highlighter; the secret message will appear!
The
Science:
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Camouflage:
Ever wonder why snowy owls and polar bears are white? Many
animals protect themselves in nature by blending in with their
environment. In the case of snowy owls and polar bears, their color
allows them to blend in with the snow where they live. Using
white crayon on white paper demonstrates this principle.
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Absorption:
Ever wonder if ink always soaks into paper? Ink, such as the
ink in a highlighter, is a liquid that will be absorbed by many
materials, including cloth and paper. But it is not absorbed
as easily by other materials, such as plastic and wax. In our
invisible ink experiment, the wax from the crayon prevented the
highlighter ink from being absorbed as easily by the paper.
This made the written area appear lighter, and allowed you to read
the message.
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