Safety Science Tools
The Power of Solar Energy
Open your students’ eyes to the importance of scientific literacy. As a Science Educator, you can help them
draw connections between science, engineering, math, and language. These lessons can help build their
confidence, strengthen their interest, and apply their knowledge to solve new problems.
The sun is a vital part of our earth’s environment. The sun provides warmth, daylight, and sun rays that
help humans, animals, and plants thrive. The sun’s energy, called solar energy, can be captured and turned
into electricity. In this experiment, students will see how they can influence the amount of energy captured from the light, using different-colored surfaces. They will also observe the different waves that make
up white (“visible”) light. And finally, experience how light energy can be converted into electricity.
There are three different parts to this activity.
A.
B.
C.
Observe how solar energy produces heat;
Break light down into its different-colored waves; and
Investigate how solar energy is converted into electricity.
PART A – OBSERVING HOW SOLAR ENERGY PRODUCES HEAT
MATERIALS
•
•
•
•
•
•
Clamp-on shop lamp (or similar)
100-watt incandescent light bulb
2 four-inch-by-four-inch cards (one black, one white)
Ice cubes of equal size (optional: add food coloring to make the results more obvious)
Toothpicks
Ruler
PREDICTIONS AND OBSERVATIONS
Share with your students that in this experiment they are going to be learning about how light energy
produces heat.
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Safety Science Tools
The Power of Solar Energy
EXPERIMENT STEPS
1. Position the lamp so it is 6 inches (15 cm)
from the table surface. Put the two cards
under the lamp, evenly positioned as shown.
2. Select two ice cubes of the same size.
3. Lay each ice cube on a toothpick, one on
each card. The toothpick should raise the
edge of the ice cube off the card just slightly.
This makes it easier to detect the melting
water.
4. Turn on the lamp. In about 5 minutes the ice
will start to react.
5. Draw the chart below on the board Ask the students to make their predictions - will both ice cubes melt
at the same rate? If not, which color will melt faster?
WHICH ICE CUBE WILL MELT FASTER?
BLACK CARD
WHITE CARD
NO DIFFERENCE
PREDICT
OBSERVE
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Safety Science Tools
The Power of Solar Energy
PART B –– BREAK LIGHT DOWN INTO ITS DIFFERENT-COLORED WAVES
MATERIALS
•
•
•
•
Flashlight with strong beam
Prism (can be purchased at a teacher supply store or online; search for “optical prism”)
Large box such as a paper case box, inside painted black
Piece of white paper, set inside the box
PREDICTIONS AND OBSERVATIONS
Ask students if they knew that white light is made up of different colors? Explain that our eyes can’t see
the different colors in white light. But white light is actually made up of all the colors in the visible light
spectrum. While showing students the prism, ask them to speculate about what might happen if you were
to send the white light through the prism?
Draw the chart below on the board and use it to record their predictions.
What Colors Can You See from the Prism?
Part B
Red
Orange
Yellow
Green
Blue
Purple
Black
Predict
Observe
EXPERIMENT STEPS
Position the flashlight so the beam shines through the prism onto the white paper inside the box. The box
will help keep extra light out of the experiment. You may need to adjust the prism or flashlight to see a
spectrum. Record the observations on the chart.
THE SCIENCE
The light we see is actually made up of many different colors of light. The human eye sees “white light”—
that’s when all the colors that make up the visible spectrum are combined. But in fact, each color has a
different wavelength.
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Safety Science Tools
The Power of Solar Energy
The different wavelengths of light travel at
different speeds, but that isn’t noticeable when
light moves through air. When light travels
through the angle of the glass prism, however,
the waves are slowed down, causing the white
single beam to split into different colors. This
range of colors is called the “spectrum of visible
light.” Traditionally, the spectrum contains seven
colors: red, orange, yellow, green, blue, indigo,
and violet A rainbow is produced when sunlight
travels through raindrops, which act like millions
of tiny prisms.
After a few minutes, examine the ice cubes and
the water underneath each one.
Ask students to verify which ice cube has melted
more? Record their observations on the chart.
Ask students if they can explain why one ice cube
melt faster than the other when both ice cubes
were the same size, and the same distance from
the lamp?
Light is a form of energy. We can turn light into
heat energy by absorbing the light.
The black card absorbs all wavelengths (all the
colors) in the light. In fact, that’s why the card
appears black to our eyes. The white card, by
contrast, reflects all wavelengths in the light.
The more wavelengths the paper absorbs, the
more heat it produces. The black card heated up
more than the white card, making the ice cube
melt faster. This is why people wear white in the
summer!
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Safety Science Tools
The Power of Solar Energy
PART C –– INVESTIGATE HOW SOLAR ENERGY IS TURNED INTO ELECTRICITY
For hundreds of years, scientists and inventors have developed different ways to harness the power of the
sun’s energy. Today, the sun’s light can be captured in solar cells that convert the energy into electricity.
Sunlight is free to use and renewable, making it a safe and efficient source of energy for our planet.
MATERIALS
• 2 solar-powered garden lights (available
at garden stores or dollar stores)
• Large box with lid such as a paper case
box, the inside lined with white paper or
painted white
PREDICTIONS AND OBSERVATIONS
Be sure to fully charge one solar light outside
before beginning the activity.
Carefully take the second light apart and
show students the internal components
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Safety Science Tools
The Power of Solar Energy
EXPERIMENT STEPS
1. Hold the working light by its base and ask students:
• Is the light on?
• How the light be turned on?
• Put the light inside the box with the lid partially closed. Is the light on now?
• If the clear light casing comes apart, remove it. Have students notice the intensity of the light with
the bulb fully exposed. The light is like a pin-dot.
• Now put the outside glass/plastic light diffuser back on. What does the light look like now? Does it
seem as bright? Why would the manufacturer add the diffuser?
2. Look at the internal components of the second light and ask students to think about:
• Where the light get its electricity from?
• If this is a “solar” light, why is there a battery inside?
• Why doesn’t the light bulb stay lit all the time when the sun is shining?
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•
•
•
Where the light get its electricity from? If this is a “solar” light, why is there a battery inside? Why doesn’t the light bulb stay lit all the time when the sun is shining? 2. Look at the internal components The Science of the second light and ask students to think about: • Where the light g
et its electricity from? • If this is a “solar” light, why is othere battery Look at the top f the ao utside oif nside? the light unit. See the smooth dark The
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UL, the UL Logo, and
SAFETY
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are registered trademarks
of
UL LLC
© 2014 to illuminate the light bulb. When it is
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unit inside a dark box, the photoresistor thinks it’s nighttime and the electrical circuit is completed. This allows electricity from the battery to illuminate the light bulb. When it Safety Science Tools
UL, the UL Logo, and SAFETY SMART are registered trademarks of UL LLC © 2014
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is daylight, the photoresistor disconnects the electrical circuit, so the light bulb turns off. During the day, the solar cell collects energy from the sun, and recharges the battery…over and over, day in and day out. (Dino, as well as leaving the graphic on the page can we also have it available for printing to be Energy
used as an activity (without the The Power
of Solar
words? Include title: How is solar power turned into electricity; Directions: Explain the steps needed to power a light bulb with solar energy.) Sunlight is The solar cell The battery absorbed by recharges the powers the the solar cell battery light bulb and converted to e
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