Part2: Build Your Own Planet
Lesson 3: Albedo
Time: approximately 40-50 minutes, plus 30 minutes for students to paint pop bottles
Materials: Text: Albedo (from web site – 1 per group)
Small thermometers, at least 0ºC to 100ºC range (2 per group)
If performed outdoors:
Plastic 2-liter soda pop bottles (2 per group)
1 can of flat white spray paint
1 can of flat black spray paint
If performed indoors:
Ring stand (1 per group)
Small lamp with outdoor floodlight or 100W light bulb (1 per group)
Black construction paper (2 sheets per group)
White construction paper (2 sheets per group)
Overview
Students explore the effect of bond albedo on a planet’s surface temperature. They
will measure the temperature of the air under black and white bottles and use this
information to draw conclusions about how the amount of energy reflected away from a
planet affects its average surface temperature.
Purpose
Students will learn that light colors reflect more energy than dark colors. As a
planet’s albedo increases, its average surface temperature will decrease. Students should
learn that they can influence the average surface temperature of their planets by
manipulating their planet’s bond albedo.
Standards
A complete list of the standards covered by this lesson is included in the Appendix
at the end of the lesson.
Procedure
Have the groups read the introduction to the lesson and make a prediction.
Does the surface of a planet affect how warm or cold it is? If so, how?
This lesson will explore these questions.
Not all the energy that arrives at a planet actually warms the planet.
Some of it is reflected back into space. The measure of the amount of energy
reflected back into space is called the “ALBEDO” of the planet. (Albedo can be
measured different ways. For this unit we will be using a particular type of
measurement called “BOND ALBEDO.”)
Rocky surfaces can vary in color, but are usually dark. Icy surfaces can be
very light or very dark depending on how much dust is mixed in with the ice—
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the more dust mixed in, the darker the ice. Liquid surfaces tend to be less dark
than rocky surfaces.
Before we do the experiment, discuss the following question with your
group and make a prediction: Will a dark-colored surface reflect more or less
heat away from a planet than a light-colored surface?
Prediction: A dark colored surface will reflect ______________ heat.
(more or less)
Instructors should decide whether to prepare the painted 2-liter pop bottles
themselves or to let the students prepare them. It is important that flat paint is used. Gloss
or semi-gloss paint may give ambiguous results.
One can of spray paint is usually enough to paint 8 to 10 bottles, both inside and
out. Painting both inside and outside will give the best results. Set the bottles on the
ground to paint the inside and then wait at least 15 minutes for them to dry to the touch.
While drying, hammer a 3’ to 4’ long stake or stick into the ground. After 15 minutes,
place the bottle upside down over the stick and spray paint the outside. Wait 5 minutes
and then check that bottles are evenly covered. It is probably a good idea to prepare the
bottles a day in advance, although the bottles should be useable within 1 hour after
painting with most types of flat spray paint.
Experiment: Testing the Effect of Albedo on Temperature
You will need:
This worksheet
2 plastic two liter pop bottles
2 small thermometers
Flat black paint
Flat white paint
Step 1: Cut off the top of the two plastic pop bottles at the top of the label.
Remove the labels.
Step 2: Paint the outside of one of the bottles black and the other bottle white.
You should also paint the inside of the bottles if you have enough paint.
This lesson can be done in lightly overcast weather, but the results will be more
noticeable in full sunlight.
On a sunny day:
Step 3: Place both thermometers in a refrigerator for at least 5 minutes (longer is
fine).
Step 4: Remove the thermometers from the refrigerators. Bring this worksheet,
both thermometers and the two painted bottles outside into the Sun.
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The thermometers do not have to be expensive. They must be short enough to fit
under the bottles. If they are short enough to lie flat under the bottles then care must be
taken to ensure that the thermometers record the temperature of the air under the bottles
and not the temperature of the surface that they are lying on. On very warm or very cold
days the temperature of the ground may be very different from the air temperature. This
can create inaccurate measurements. The problem can be remedied by having groups
bring out a book large enough to place both bottles on. The groups can place both
thermometers on the book and then cover the thermometers with the bottles.
Teachers should caution students to be careful where they stand during the test so
that their shadows are not falling on either of the bottles.
Step 5: Place the thermometers on the ground. Cover one with the white bottle
and the other with the black bottle. (If the thermometer is longer than the
diameter of the bottle you will need to stand the thermometer up inside the
bottle.) Wait at least three minutes.
Step 6: Lift up the white bottle and check the temperature on the thermometer.
Record the temperature here: _________ º F / C (circle).
Note: Circle “F” if you recorded the temperature in degrees Fahrenheit. Circle
“C” if you recorded it in degrees Celsius. Make sure to use the same
temperature scale throughout this experiment.
Step 7: Lift up the black bottle and check the temperature on the thermometer.
Record the temperature here: _________ º F / C (circle).
Inexpensive classroom thermometers can be inaccurate. By switching the
thermometers and repeating the test any inaccuracies will be canceled out. Teachers may
consider eliminating the explanation below from the student copies of the assignment and
asking students how they might compensate for any potential inaccuracies.
Because there might be small differences in the thermometers, we need to
swap the thermometers between the two bottles and repeat the experiment,
so continue on to Steps 8 - 10.
Step 8: Take the thermometer that was under the white bottle and place it
under the black bottle. Put the thermometer that was under black bottle under
the white bottle. Wait at least three minutes.
Step 9: Lift up the white bottle and check the temperature on the thermometer.
Record the temperature here: _________ º F / C (circle).
Step 10: Lift up the black bottle and check the temperature on the
thermometer. Record the temperature here: _________ º F / C (circle).
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Step 11: Add together the two temperature readings under the white bottle
recorded in Steps 6 & 9.
Total temperature under the white bottle: _______________ º F / C (circle).
Add together the two temperature readings under the black bottle recorded in
Steps 7 & 10.
Total temperature under the black bottle: _______________ º F / C (circle).
Questions: (Answers included)
1) Which color bottle had the higher total temperature?
_________________. (Black)
2) Which color bottle had the lower total temperature?
_________________. (White)
3) Which color bottle reflected away more heat?
__________________. (White)
4) Since albedo is the measure of how much energy is reflected away, which
color bottle had the higher albedo?
____________. (White)
5) Was the difference in total temperature between the two bottles great or
small?
______________. (Either answer is permissible depending on the group’s
perspective, but albedo has a smaller impact on a planet’s average surface
temperature than the mass of the star it is orbiting or its distance from that star.)
6) Do you think albedo has a great effect or a small effect on a planet’s surface
temperature?
_____________. (Either answer is permissible as long as it is consistent
with the group’s answer to question 5.)
Based on what you just discovered about the black and white bottles, circle the
correct answers to the next three questions.
Answers are given in bold.
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7) If all other conditions were the same, you would expect a planet with a high
albedo to have a (higher / lower) average surface temperature than a planet
with a low albedo.
8) If all other conditions were the same, a planet with a dark-colored surface
would have a (higher / lower) average surface temperature than a planet with
a light-colored surface.
9) Much of the Earth’s north and south Polar Regions are covered by ice caps.
This ice is very light-colored, almost white. This means that the ice caps have a
(higher / lower) albedo than the rest of Earth’s surface. As the ice caps melt and
become smaller the Earth’s albedo (increases / decreases) and the Earth
becomes (cooler / warmer). If the ice caps start increasing the Earth’s albedo
would (increase / decrease) and the Earth would become (cooler / warmer).
Slide #1 can be used when discussing the above question.
10) In your own words, explain how the average surface temperature of a
planet changes as its BOND ALBEDO changes. ______________________
_____________________________________________________________
11) Now think about the average surface temperature of the planet you are
exploring. Based on what you have discovered with the Planet Temperature
Calculator, is the average surface temperature of your planet too hot, too cold
or about right? ______________________________. Do you want your planet
to have a high or a low albedo? ____________
Slides #2-3 can be used when discussing the following question.
Look at question 5 of the Planet Preference Survey to find the type of surface
you selected for your planet. The surface you chose will restrict the range of
numbers that you may enter for BOND ALBEDO in the planet temperature
program.
If you chose “Liquid” choose a number between 15 and 25.
If you chose “Solid” choose a number between 1 and 15 for a rocky
surface, 50 and 80 for a fresh ice covered surface, or 10 and 50 for an old, dirty
ice covered surface.
If you chose “Mixture” decide whether your planet is mostly rock, mostly
liquid or mostly ice. You should choose a number close to the allowable range
for that surface (check the ranges listed above) but it can be a little higher or
lower, depending on what else is on your planet’s surface.
Our planet has a BOND ALBEDO of ___________.
The groups should use this value for BOND ALBEDO for the remaining lessons
of this unit.
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While it is recommended that this activity be performed outdoors, it is possible to
modify it so that it can be done indoors if the weather does not cooperate. The following
is the procedure for a similar indoor activity:
1) Suspend the lamp upside down in the ring stand so that the floodlight or 100W
light bulb is pointing downward.
2) Adjust the ring stand so that the floodlight bulb is approximately 6” (15 cm)
above the table top, or 4” (10 cm) if using a 100W bulb.
3) Place one sheet of white paper and one sheet of black paper side-by-side under
the light bulb. Adjust the ring stand so that the center of the bulb is directly
over the line where the two sheets of paper meet.
4) Place one thermometer on the white paper approximately 3” (8 cm) from the
line where the 2 sheets of paper meet and the other thermometer in the same
relative position on the black paper. If desired, teachers can have students
measure and mark the positions on the papers where the thermometers will be
placed beforehand, although this is not critical. It is important, however, that
both thermometers are about the same distance from the bulb.
5) Cover the thermometer on the white paper with the 2nd sheet of white paper
and the thermometer on the black paper with the 2nd black paper. The top and
bottom papers should all meet at the same line.
6) Turn on the light bulb and wait approximately 3 minutes if using the floodlight
or 5 minutes if using the 100W bulb.
7) Uncover the thermometer on the white paper and record the temperature.
8) Uncover the thermometer on the black paper and record the temperature.
9) Switch the thermometers and repeat.
Students will need a different worksheet if performing this activity indoors. A
modified worksheet is available in Appendix B
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Appendix A
Standards Addressed
Benchmarks (Grades 3 through 5)
1B – Scientific Inquiry
Scientific investigations may take many different forms, including observing what things are like
or what is happening somewhere, collecting specimens for analysis, and doing experiments.
Investigations can focus on physical, biological, and social questions.
Results of scientific investigations are seldom exactly the same, but if the differences are large, it
is important to try to figure out why. One reason for following directions carefully and for
keeping records of one's work is to provide information on what might have caused the
differences.
3A – Technology and Society
Measuring instruments can be used to gather accurate information for making scientific
comparisons of objects and events and for designing and constructing things that will work
properly.
4E – Energy Transformation
Some materials conduct heat much better than others. Poor conductors can reduce heat loss.
11A – Systems
In something that consists of many parts, the parts usually influence one another.
11B - Models
Seeing how a model works after changes are made to it may suggest how the real thing would
work if the same were done to it.
12D – Communication Skills
Use numerical data in describing and comparing objects and events.
12E – Critical-Response Skills
Recognize when comparisons might not be fair because some conditions are not kept the same.
Seek better reasons for believing something than "Everybody knows that . . ." or "I just know"
and discount such reasons when given by others.
Benchmarks (Grades 6 through 8)
1C – The Scientific Enterprise
Accurate record-keeping, openness, and replication are essential for maintaining an
investigator's credibility with other scientists and society.
3A – Technology and Society
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Technology is essential to science for such purposes as access to outer space and other remote
locations, sample collection and treatment, measurement, data collection and storage,
computation, and communication of information.
4F – Motion
Light from the sun is made up of a mixture of many different colors of light, even though to the
eye the light looks almost white. Other things that give off or reflect light have a different mix of
colors.
11A – Systems
A system can include processes as well as things.
Thinking about things as systems means looking for how every part relates to others. The output
from one part of a system (which can include material, energy, or information) can become the
input to other parts. Such feedback can serve to control what goes on in the system as a whole.
11B – Models
Models are often used to think about processes that happen too slowly, too quickly, or on too
small a scale to observe directly, or that are too vast to be changed deliberately, or that are
potentially dangerous.
12A – Values and Attitudes
Know that hypotheses are valuable, even if they turn out not to be true, if they lead to fruitful
investigations.
12C – Manipulation and Observation
Read analog and digital meters on instruments used to make direct measurements of length,
volume, weight, elapsed time, rates, and temperature, and choose appropriate units for reporting
various magnitudes.
Benchmarks (Grades 9 through 12)
1A – The Scientific World View
Scientists assume that the universe is a vast single system in which the basic rules are the same
everywhere. The rules may range from very simple to extremely complex, but scientists operate
on the belief that the rules can be discovered by careful, systematic study.
1B – Scientific Inquiry
Investigations are conducted for different reasons, including to explore new phenomena, to
check on previous results, to test how well a theory predicts, and to compare different theories.
National Standards (Grades 5-8)
Understandings about Scientific Inquiry
Technology used to gather data enhances accuracy and allows scientists to analyze and quantify
results of investigations.
Transfer of Energy
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The sun is a major source of energy for changes on the earth's surface. The sun loses energy by
emitting light. A tiny fraction of that light reaches the earth, transferring energy from the sun to
the earth. The sun's energy arrives as light with a range of wavelengths, consisting of visible
light, infrared, and ultraviolet radiation.
Nature of Science
Scientists formulate and test their explanations of nature using observation, experiments, and
theoretical and mathematical models. Although all scientific ideas are tentative and subject to
change and improvement in principle, for most major ideas in science, there is much
experimental and observational confirmation. Those ideas are not likely to change greatly in the
future. Scientists do and have changed their ideas about nature when they encounter new
experimental evidence that does not match their existing explanations.
National Standards (Grades 9-12)
Understandings about Scientific Inquiry
Scientists rely on technology to enhance the gathering and manipulation of data. New techniques
and tools provide new evidence to guide inquiry and new methods to gather data, thereby
contributing to the advance of science. The accuracy and precision of the data, and therefore the
quality of the exploration, depends on the technology used.
Energy in the Earth System
Global climate is determined by energy transfer from the sun at and near the earth's surface.
This energy transfer is influenced by dynamic processes such as cloud cover and the earth's
rotation, and static conditions such as the position of mountain ranges and oceans.
Indiana Standards
Grade 5
English/Language Arts – Comprehension
5.2.2 – Analyze text that is organized in sequential or chronological order.
Science – Communication Skills
5.2.7 – Read and follow step-by-step instructions when learning new procedures.
Matter and Energy
5.3.10 – Investigate that some materials conduct heat much better than others, and poor
conductors can reduce heat loss.
Numbers
5.5.1 – Make precise and varied measurements and specify the appropriate units.
Grade 6
Mathematics – Measurement
6.5.1 – Select and apply appropriate standard units and tools to measure length, area, volume,
weight, time, temperature, and the size of angles.
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Science – Interdependence of Life and Evolution
6.4.10 – Describe how life on Earth depends on energy from the sun.
Grade 7
Mathematics – Data Analysis and Probability
7.6.2 – Make predictions from statistical data.
Science – Manipulation and Observation
7.2.6 – Read analog and digital meters on instruments used to make direct measurements
of length, volume, weight, elapsed time, rates, or temperatures, and choose appropriate
units.
Matter and Energy
7.3.11 – Explain that the sun loses energy by emitting light. Note that only a tiny fraction
of that light reaches Earth. Understand that the sun’s energy arrives as light with a wide
range of wavelengths, consisting of visible light and infrared and ultraviolet radiation.
Grade 8
Science – Communication
8.2.7 – Participate in group discussions on scientific topics by restating or summarizing
accurately what others have said, asking for clarification or elaboration, and expressing
alternative positions.
Part2: Build Your Own Planet
Appendix B
Build Your Own Planet
Lesson 3: Albedo
Group: _____________________________
Does the surface of a planet affect how warm or cold it is? If so, how? This
lesson will explore these questions.
Not all the energy that arrives at a planet actually warms the planet. Some
of it is reflected back into space. The measure of the amount of energy reflected
back into space is called the “ALBEDO” of the planet. (Albedo can be measured
different ways. For this unit we will be using a particular type of measurement
called “BOND ALBEDO.”)
Rocky surfaces can vary in color, but are usually dark. Icy surfaces can be
very light or very dark depending on how much dust is mixed in with the ice—
the more dust mixed in, the darker the ice. Liquid surfaces tend to be less dark
than rocky surfaces.
Before we do the experiment, discuss the following question with your
group and make a prediction: Will a dark-colored surface reflect more or less
heat away from a planet than a light-colored surface?
Prediction: A dark colored surface will reflect ______________ heat.
(more or less)
Experiment: Testing the Effect of Albedo on Temperature
You will need:
This worksheet
2 small thermometers
Ring stand
Small lamp with outdoor floodlight or 100W light bulb
2 sheets of black construction paper
2 sheets of white construction paper
Step 1: Place both thermometers in a refrigerator for at least 5 minutes (longer is
fine).
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Step 2: Place the lamp upside down in the ring stand so that the floodlight or
100W light bulb is pointing downward.
Step 3: Adjust the ring stand so that the floodlight bulb is approximately 6” (15
cm) above the table top, or 4” (10 cm) if using a 100W bulb.
Step 4: Place one sheet of white paper and one sheet of black paper side-by-side
under the light bulb. Adjust the ring stand so that the center of the bulb is
directly over the line where the two sheets of paper meet.
Step 5: Remove the thermometers from the refrigerator. Place one thermometer
on the white paper about 3” (8 cm) from the line where the 2 sheets of paper
meet and the other thermometer in the same position on the black paper.
Step 6: Cover the thermometer on the white paper with the 2nd sheet of white
paper and the thermometer on the black paper with the 2nd black paper. The
top and bottom papers should all meet at the same line.
Step 7: Turn on the light bulb and wait 3 minutes if using the floodlight or 5
minutes if using the 100W bulb.
Step 8: Uncover the thermometer under the white paper and note the
temperature.
Record the temperature here: _________ º F / C (circle).
Note: Circle “F” if you recorded the temperature in degrees Fahrenheit. Circle “C”
if you recorded it in degrees Celsius. Make sure to use the same temperature
scale throughout this experiment.
Step 9: Uncover the thermometer under the black paper and note the
temperature.
Record the temperature here: _________ º F / C (circle).
Because there might be small differences in the thermometers, we need to swap
the thermometers between the two bottles and repeat the experiment, so
continue on to Steps 10 - 12.
Step 10: Take the thermometer that was under the white paper, place it on the
black paper and cover it with the 2nd sheet of black paper. Put the thermometer
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that was under black paper on the white paper and cover it with the 2nd white
paper. Wait at least three minutes if using the floodlight or 5 minutes if using the
100W bulb.
Step 11: Uncover the thermometer under the white paper and note the
temperature. Record the temperature here: _________ º F / C (circle).
Step 12: Uncover the thermometer under the black paper and note the
temperature.
Record the temperature here: _________ º F / C (circle).
Step 11: Add together the two temperature readings under the white paper
recorded in Steps 8 & 11.
Total temperature under the white paper: _______________ º F / C (circle).
Add together the two temperature readings under the black paper recorded in
Steps 9 & 12.
Total temperature under the black paper: _______________ º F / C (circle).
Questions:
1) Which color paper had the thermometers with higher total temperature?
_________________.
2) Which color paper had the lower total temperature?
_________________.
3) Which color paper reflected away more heat?
__________________.
4) Since albedo is the measure of how much energy is reflected away, which
color paper had the higher albedo?
____________.
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5) Was the difference in total temperature between the two papers great or
small?
______________.
6) Do you think albedo has a great effect or a small effect on a planet’s surface
temperature?
_____________.
Based on what you just discovered about the black and white papers, circle the
correct answers to the next three questions.
7) If all other conditions were the same, you would expect a planet with a high
albedo to have a (higher / lower) average surface temperature than a planet
with a low albedo.
8) If all other conditions were the same, a planet with a dark-colored surface
would have a (higher / lower) average surface temperature than a planet with a
light-colored surface.
9) Much of the Earth’s north and south Polar Regions are covered by ice caps.
This ice is very light-colored, almost white. This means that the ice caps have a
(higher / lower) albedo than the rest of Earth’s surface. As the ice caps melt and
become smaller the Earth’s albedo (increases / decreases) and the Earth
becomes (cooler / warmer). If the ice caps start increasing the Earth’s albedo
would (increase / decrease) and the Earth would become (cooler / warmer).
10) In your own words, explain how the average surface temperature of a
planet changes as its BOND ALBEDO changes. ________________
__________________________________________________________________
11) Now think about the average surface temperature of the planet you are
exploring. Based on what you have discovered with the Planet Temperature
Calculator, is the average surface temperature of your planet too hot, too cold or
about right? ______________________________. Do you want your planet to
have a high or a low albedo? ____________
Part2: Build Your Own Planet
Look at question 5 of the Planet Preference Survey to find the type of surface you
selected for your planet. The surface you chose will restrict the range of numbers
that you may enter for BOND ALBEDO in the planet temperature program.
If you chose “Liquid” choose a number between 15 and 25.
If you chose “Solid” choose a number between 1 and 15 for a rocky
surface, 50 and 80 for a fresh ice covered surface, or 10 and 50 for an old, dirty
ice covered surface.
If you chose “Mixture” decide whether your planet is mostly rock, mostly
liquid or mostly ice. You should choose a number close to the allowable range
for that surface (check the ranges listed above) but it can be a little higher or
lower, depending on what else is on your planet’s surface.
Our planet has a BOND ALBEDO of ___________.