Carolina Power House Kit - Manual (Page 4)

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Light and heat from
the sun
Heating water is nice enough. But the sun’s
light can be used to do other things as well.
First, though, you have to learn a little about
the behavior of light.
A star made of light
A candle’s flame illuminates, which is
to say it emits light. What happens to the light
it sends out?
An adult should be present for this experiment!
You will need
“Light path” die-cut piece, tealight candle,
matches, white paper, tape
Experiment
1. Remove the “light path” piece from the
die-cut sheet. Bend it together into a circle and
secure it with some tape.
2. Place the circle on a sheet of white paper in
a darkened room. Set a tealight candle in the
center and light it. What do you see?
Explanation
A ray of light streams through each one of the
slits. It runs perfectly straight. So light spreads
out equally in all directions. As the rays of light
get farther from their source, they diverge far-
ther and farther from each other.
=
Do the sun’s rays also
diverge?
Strange: Objects in sunlight cast sharp
shadows. How can that be, if rays of light move
apart from one another as soon as they leave
their source?
You will need
“Light path” die-cut piece, roof piece, white
paper, lamp
Experiment
1. Remove the tape and pull the strip apart
again. Tape it to the roof of your experimental
house and observe the patterns that the sun
makes as it shines through it.
2. Unlike the candle in the previous experiment,
the sun is very far away from the “comb.” Use a
desk lamp or flashlight to experiment with the
way that the distance between the light source
and the “comb” can affect the shadows.
Explanation
Rather than diverging, the rays of the sun run
parallel — that is, they always keep the same
distance from one another. That is due to the
unbelievably huge distance of the sun from
Earth. That becomes clear in the second pat of
the experiment: The greater the distance be-
tween the “comb” and the light source, the less
the rays diverge.
Appearances are deceiving: The sun’s rays only seem to
diverge. In reality, they run parallel.
EXP.
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EXP.
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