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Comparing how light refracts through different prisms. |
OBJECTIVES:
VOCABULARY:
MATERIALS:
BACKGROUND:
Emphasize that this segment concentrates on visible light which is a part
of the electromagnetic wave spectrum. Review how light carries energy in
tiny packets of electromagnetic radiation called photons. Light travels at
296,000 meters per second or 186,000 miles per second and doesn't need a
medium to travel in. All colors of light travel at the same speed, but
they have different wave frequencies (short and long waves).
Light can be reflected or refracted. In reflection, light bounces off a
surface and is diffused. Light travels in a straight line and refraction
is the bending of this light. The light breaks up into different
frequencies therefore causing a rainbow or a "broken" look.
This
activity demonstrates different components of refracted light. If students
do not know the light spectrum, give them the following pneumonic device
to help them remember. ROY G. BIV = red, orange, yellow, green, blue,
indigo and violet.
PROCEDURE:
1.
Read
Light Magic
2.
Discuss
with students what a prism does to light.
It refracts.
Go over that rainbows are only created
when there is refraction.
3. Notice that you have 3 different types of prisms. One of them is a right angle prism. Go over with student the difference. Which on is longer? Which is thicker? Ask them to describe the prisms.
4.
Tell them they are going to do an experiment.
Do prisms make better rainbows inside or
outside. 5. Then go outside and use natural light. If the day is overcast it may be difficult to get a rainbow outside. But then, that should be part of the discussion. Ask them why there is no rainbow.
6.
Go back inside and discuss what they saw. Let them decide which made
the best rainbow of the 3 shapes and where did they create the best
rainbow. Ask questions again about Roy G. Biv. Please note
repetition is important. 7. If you have time, have students color the ROY G BIV Rainbow.
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