Did you know . . .
. . . that there is a world championship for solar cars?
Every year, a solar car world championship is held in Australia. In the contest, the cars have to drive about 3,000 km
across the entire continent. The one that finishes first is the world champion. The fastest solar cars reach speeds of
over 100 km/h, driving on normal roads. During the race, the solar cars are accompanied by separate cars driven by
their team members. Most of the teams in the contest come from universities. Many of the electricians and mechan-
ics are students who take part in the race for fun. All the race cars are unique models, each one different from the next.
That means they are also very expensive. These solar race cars typically cost more than $300,000 to build.
The Artificial Sun’s Power
Why doesn’t the solar engine run in every part of your
home — even in a particularly bright room? The next
experiment should shed some light on this.
Experiment 5
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You will need: solar model and a light in your
house that is strong enough to move the solar engine
when you hold the engine directly beneath it
Instructions
Hold your solar model directly under the light that
is strong enough to run the engine. Then gradually
increase the distance between the lamp and solar
module. What happens?
Results
The farther away you get from the lamp, the less light
is emitted from it. You can see that particularly clearly
on a street at night, when a car drives toward you with
its headlights on. When the car is still far away, all you
see is two small points of light. But when it drives
by you, the light of the car is much, much brighter.
Because the brightness of a light source drops with
distance, the solar cell won’t get enough light to run
the motor when it is too far away.
Ambient Light
During the day, daylight enters your home. A term for
this kind of light is ambient light (literally meaning
“surrounding light”). In the next experiment, we will
see if ambient light has any effect on the solar cell.
Experiment 6
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You will need: solar model, a long ruler, a light
in your house that is strong enough to run the solar
engine when you hold the module directly beneath it.
A desk lamp works the best.
Instructions
In the middle of a sunny day, hold your model under a
light that is strong enough to run the engine. In-
crease the distance until the engine stops. There has
to be a lot of sunlight entering the room. Measure
the distance between the lamp and the model. Write
down the measurement. Repeat the experiment after
sundown and compare the distances measured. If
you don’t want to wait until evening, you can just shut
the blinds.
Results
During the day — even when the sky is overcast —
sunlight enters your house. The solar cell can make
The Honda Dream, a spectacular solar race car.
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