Part2: Build Your Own Planet

Lesson 4: Atmosphere Time: approximately 30 minutes, longer if the optional demonstration and activity are included Materials: Text: Greenhouse effect (from web site – 1 per group) Small thermometers, at least 0ºC to 100ºC range (2 per group) Clear plastic 2-liter soda pop bottle (1 per group) If performed indoors: Ring stand (1 per group) Small lamp with outdoor floodlight or 100W light bulb (1 per group) Newspaper, magazine, or a few sheets of 8.5” x 11” paper (1 per group)

Materials for optional demonstrations: Demonstration: Empty aluminum soda pop can Hot plate or Bunsen burner with stand Tongs Tub of water Activity Small cup (1 per group) 10cc medical syringe, without needle (1 per group)

Overview The students will measure the temperature of the air inside and outside of a clear plastic pop bottle and use these results to infer the effect of a planet’s atmosphere on its average surface temperature.

Purpose This lesson teaches that a planet’s atmosphere can create a greenhouse effect that raises the planet’s average surface temperature. Students should learn that they can influence the average surface temperature of their planets by manipulating their planet’s greenhouse effect.

Standards A complete list of the standards covered by this lesson is included in the Appendix at the end of the lesson.

Procedure

Students should read the introduction to Lesson 4:

Does the atmosphere of a planet affect its surface temperature? If so, how? This lesson will explore that question. Part2: Build Your Own Planet

The gases that surround a planet are called its “atmosphere.” A planet’s atmosphere creates pressure at its surface, because gravity is constantly trying to pull all the gases down toward the center of the planet. If an atmosphere is too thick it may create crushing pressures, like on Jupiter.

This can be illustrated quite dramatically by the following optional demonstration: 1) Fill an empty aluminum soda pop can with about ¼” to ½” of water. 2) Place the can on a hot plate turned up to high or on a stand over a Bunsen burner. Wait until the water inside the can is boiling rapidly and steam can be seen coming out the opening. 3) Using a pair of tongs, lift the can off the heat and quickly place the can upside down in a tub of water so that the opening is under the water. The can will rapidly collapse. This demonstration illustrates the strength of the Earth’s atmospheric pressure. Normally the pressure inside the can is the same as the pressure outside the can. When water changes from a liquid to a gas its volume increases by around a factor of 1,000. Because the water vapor is denser than the surrounding air, the air is pushed out of the top of the can as the can fills up with steam. When steam is visible coming out of the top of the can it indicates that most of the air has already been pushed out. Putting the can into the tub of water cools it rapidly, converting the water vapor back into liquid and reducing its volume a thousand fold. If the opening of the can were out of the water, air would rush into it to replace the condensed water vapor—equalizing the pressures inside and outside the can—and there would be no collapse. But when the opening of the can is placed in the water there is no way for air to get back into the can as the steam condenses back into a liquid. The condensing water vapor leaves a partial vacuum inside the can, meaning that there is much less pressure inside the can than outside it. The vacuum itself is not what causes the can to collapse—this demonstration would not work in outer space, for example—but rather the fact that there is not enough pressure inside the can to balance the atmospheric pressure outside the can. It is the Earth’s atmospheric pressure that causes the can to collapse.

If there is too little atmosphere there will not be enough pressure at the surface to keep water as a liquid. As atmospheric pressure drops, the boiling point of water drops. At extremely low pressures the boiling point drops below the melting point. This means that water can never exist as a liquid—it changes directly from a solid to a gas. This is what happens on Mars. Part2: Build Your Own Planet

To illustrate this, perform the following optional activity: 1) Distribute a small cup and the medical syringes. (These are easily available at most medical supply stores or over the internet. You do not need a prescription to buy syringes.) You should probably have a cup and a syringe for yourself so that you can demonstrate the procedure to the students as you are giving directions. 2) Have students pour about an inch of water into the cups and then place the end of the syringes into the water. 3) Pull out on the plunger, drawing water up into the syringe, until there is about ¼” of water in the syringe. 4) Turn the syringe upside down and tap on it until all bubbles have risen to the top, then push up lightly on the plunger until all the air is pushed out and a very small amount of water beads up (or comes out of) the end. 5) This next part is a little difficult and may take some practice. Cover the end of the syringe tightly with your thumb. Turn the syringe right side up and pull up rapidly on the plunger. You should see bubbles start to form in the water. (Caution: If you let go of the plunger after you have pulled it up it will snap back down to its starting position, forcing a very thin stream of water into your thumb. This will sting a little, but is harmless.) If the syringe end is well sealed by your thumb, there is no way that air can get inside as you pull on the plunger. The mass of the water remains constant, but the volume inside the syringe increases as you pull up on the plunger. The same mass distributed over a greater volume results in decreased pressure inside the syringe. Eventually the pressure decreases so much that the boiling point of water drops below room temperature and the water begins to boil without heating up. The bubbles seen are evidence of liquid water being converted into gas. Note: if there is too much water in the syringe the pressure inside will never drop low enough for the water to boil. It is recommended that instructors test this demonstration beforehand to determine the optimum amount of water in the syringe. Students should continue reading the introduction and make a prediction.

Before we do the experiment, discuss the following question with your group and make a prediction: How might an atmosphere affect a planet’s average surface temperature?

Prediction: A planet’s atmosphere keeps ______heat at its surface. (more or less)

Instructors should decide whether to prepare the 2-liter pop bottles themselves or to let the students prepare them. Allow an extra five or ten minutes if the students prepare them. Part2: Build Your Own Planet

Experiment: Test the Effect of the Atmosphere on Temperature

You will need: This worksheet A clear plastic two liter pop bottle 2 small thermometers

Step 1: Cut off the top of the plastic bottle at the top of the label. Remove the labels.

This lesson can be done in lightly overcast weather, but the results will be more noticeable in full sunlight.

On a sunny day: Step 2: Place the thermometers in a refrigerator for at least 5 minutes (longer is fine).

Step 3: Remove the thermometers from the refrigerator. Bring this worksheet, both thermometers and the bottle outside into the Sun.

Step 4: Place both thermometers on the ground near each other in the Sun. Cover one of the thermometers with the clear bottle. (If the thermometer is longer than the diameter of the bottle you will need to stand the thermometer up inside the bottle.) Be sure that the other thermometer does not lie in the shadow of the bottle. Wait at least three minutes.

Step 4 can be problematic. If the thermometer is longer than the diameter of the bottle it will stand up inside the bottle while the other thermometer is lying flat on the ground. The thermometer inside the bottle will measure the air temperature inside the bottle, but the other thermometer will measure the ground temperature rather than the air temperature. 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 thermometers on. The groups can place both thermometers on the book and then cover one of the thermometers with the bottle. As long as the book has a glossy surface and is brought outside as the same time as the other supplies there should not be a significant difference between the air temperature and the surface temperature of the book. Teachers should caution students to be careful where they stand during the test so that their shadows are not falling on either of the thermometers. Part2: Build Your Own Planet

Step 5: Lift up the 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 6: Check the temperature of the other 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 and repeat the experiment, so continue on to Steps 7 - 9.

Step 7: Take the thermometer that was under the bottle and place it on the ground. Put the other thermometer under the bottle. Wait at least three minutes.

Step 8: Lift up the bottle and check the temperature on the thermometer. Record the temperature here: ______º F / C (circle).

Step 9: Check the temperature of the other thermometer. Record the temperature here: ______º F / C (circle).

Step 10: Add the temperatures under the bottle recorded in Steps 5 & 8. Total temperature under the bottle: ______º F / C (circle).

Add the temperatures outside the bottle recorded in Steps 6 & 9. Total temperature outside of the bottle: ______º F / C (circle).

Questions: (Answers included) Part2: Build Your Own Planet

1) Was the temperature under the bottle higher or lower than the temperature outside of the bottle? ______. Should be higher

2) Which thermometer—the one outside of the bottle or the one under the bottle—represents the effect of the atmosphere?

______. The one under the bottle.

3) How does the atmosphere affect a planet’s temperature?

______. Answers may vary, but students should be aware that an atmosphere can raise the temperature.

You should have discovered that the temperature under the bottle was warmer than the temperature outside the bottle. The bottle acted as a kind of greenhouse atmosphere around the thermometer. It allowed sunlight in to warm the thermometer and then trapped it inside so it could raise the temperature even higher. You’ve felt the same effect happen if you’ve ever gotten into a car with its windows rolled up on a hot, sunny day.

The ability of an atmosphere to trap heat is called the GREENHOUSE EFFECT. Not all the gases in an atmosphere are greenhouse gases, that is, gases that trap heat. Carbon dioxide, methane, and ozone are three greenhouse gases that we have in Earth’s atmosphere, but there are others.

On Earth, nitrogen and oxygen make up 99% of the gases in our atmosphere. Neither of these gases trap heat. Most of Earth’s greenhouse effect comes from carbon dioxide and methane. But only 0.03% of our atmosphere is carbon dioxide, and methane makes up only 0.002%. Yet both of these gases have a great effect on our average surface temperature.

Check the Planet Temperature Calculator to see how important these tiny amounts of carbon dioxide and methane are in warming our planet. (www.astro.indiana.edu/~gsimonel/temperature1.html) Enter Part2: Build Your Own Planet

normal Earth values for MASS (1), DISTANCE (1), and BOND ALBEDO (29), but set the GREENHOUSE EFFECT to “0,” (no effect).

4) What is Earth’s average surface temperature with no GREENHOUSE EFFECT? ______º F / C (circle). -10ºC or 14ºF

Venus has a GREENHOUSE EFFECT 200 times as powerful as Earth’s. Because of this, Venus’ average surface temperature is around 460ºC, much too hot to support life as we know it. What would Venus be like without any GREENHOUSE EFFECT? We can find out by entering Venus’ values for distance and albedo into the planet temperature program and setting its GREENHOUSE EFFECT to 0. Enter these values into the program: MASS: 1 DISTANCE: 0.72 BOND ALBEDO: 75 GREENHOUSE EFFECT: 0

5) What is Venus’ average surface temperature with no GREENHOUSE EFFECT? ______º F / C (circle). -35ºC or -31ºF

6) Would Venus still be too hot to support life with no GREENHOUSE EFFECT? ______. No

7) Would Venus be habitable with no GREENHOUSE EFFECT? ___. No Why or why not? ______. It would be too cold.

Some students may notice that Venus without any greenhouse warming would be colder than Earth even though it is closer to the Sun. This is because Venus has a BOND ALBEDO of 75, meaning that 75% of the Sun’s energy that reaches the planet is reflected away into space without heating the planet.

8) Now think about the average surface temperature of the planet you are exploring. Based on what you have discovered with the planet temperature program, is the average surface temperature of your planet too hot, too cold or about right? ______.

9) Based on what you now know about greenhouse effect, do you want your planet to have a strong or weak effect? ______. Part2: Build Your Own Planet

Look at number 3 of the planet preference survey to find out the type of atmosphere on your planet. The thickness of the atmosphere you chose will restrict the range of numbers that you may enter for GREENHOUSE EFFECT in the planet temperature program. If you chose “Trace” choose a number between 0 and 0.4. If you chose “Thin” choose a number between 0.4 and 3. If you chose “Thick” choose a number between 3 and 300.

Our planet has a GREENHOUSE EFFECT of ______.

The groups should use this value for GREENHOUSE EFFECT for the remaining lessons of this unit. 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 12” (30 cm) above the table top, or 6” (8 cm) if using a 100W bulb. 3) Place a thermometer inside the clear plastic soda pop bottle. Place the bottle approximately 1” from the floodlight or ½” from the 100W bulb. 4) Set a second thermometer at about the same distance from the light as the thermometer inside the bottle. If the thermometer inside the bottle is standing, lean the other thermometer against any non-reflective object at about the same angle as the thermometer inside the bottle. 5) Turn on the floodlight or 100W bulb and allow thermometers to sit in the light for three minutes. 6) After three minutes, lightly fan the thermometers with the newspaper, magazine or papers for one minute. (Heat energy from the Sun bounces off a planet’s surface and radiates back into space. Fanning the thermometers simulates this effect. The pop bottle, like our atmosphere, traps some of this heat along the way.) Do not fan so hard that the thermometers move or the pop bottle falls over. 7) Turn off the light and record the temperatures of the two thermometers. 8) Switch the two thermometers and repeat steps 5 through 7. Students will need a different worksheet if performing this activity indoors. A modified worksheet is available in Appendix B

Part2: Build Your Own Planet

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.

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 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. Part2: Build Your Own Planet

4B – The Earth The earth is mostly rock. Three-fourths of its surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin blanket of air. It is the only body in the solar system that appears able to support life. The other planets have compositions and conditions very different from the earth's.

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.

4B – The Earth Weather (in the short run) and climate (in the long run) involve the transfer of energy in and out of the atmosphere. Solar radiation heats the land masses, oceans, and air. Transfer of heat energy at the boundaries between the atmosphere, the land masses, and the oceans results in layers of different temperatures and densities in both the ocean and atmosphere. The action of gravitational force on regions of different densities causes Part2: Build Your Own Planet them to rise or fall-and such circulation, influenced by the rotation of the earth, produces winds and ocean currents.

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 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.

The Earth and the Processes That Shape It Part2: Build Your Own Planet

5.3.4 – Investigate that when liquid water disappears it turns into a gas (vapor) mixed into the air and can reappear as a liquid when cooled or as a solid if cooled below the freezing point of water.

Matter and Energy 5.3.8 – Investigate, observe, and describe that heating and cooling cause changes in the properties of materials, such as water turning into steam by boiling and water turning into ice by freezing. Notice that many kinds of changes occur faster at higher temperatures.

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.

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.

Earth and Space Science The Earth ES.1.11 – Examine the structure, composition, and function of Earth’s atmosphere. Include the role of living organisms in the cycling of atmospheric gases. Part2: Build Your Own Planet

ES.1.13 – Explain the importance of heat transfer between and within the atmosphere, land masses, and oceans. Part2: Build Your Own Planet

Appendix B

Build Your Own Planet Lesson 4: Atmosphere

Group: ______

Does the atmosphere of a planet affect its surface temperature? If so, how? This lesson will explore that question.

The gases that surround a planet are called its “atmosphere.” A planet’s atmosphere creates pressure at its surface, because gravity is constantly trying to pull all the gases down toward the center of the planet. If an atmosphere is too thick it may create crushing pressures, like on Jupiter. If there is too little atmosphere there will not be enough pressure at the surface to keep water as a liquid. As atmospheric pressure drops, the boiling point of water drops. At extremely low pressures the boiling point drops below the melting point. This means that water can never exist as a liquid—it changes directly from a solid to a gas. This is what happens on Mars.

Before we do the experiment, discuss the following question with your group and make a prediction: How might an atmosphere affect a planet’s average surface temperature?

Prediction: A planet’s atmosphere keeps ______heat at its surface. (more or less)

Experiment: Test the Effect of the Atmosphere on Temperature

You will need: This worksheet A clear plastic two liter pop bottle 2 small thermometers Part2: Build Your Own Planet

A ring stand A small lamp with a floodlight or 100W light bulb A newspaper, magazine or several sheets of paper

Step 1: Cut off the top of the plastic bottle at the top of the label. Remove the labels.

Step 2: Place the thermometers in a refrigerator for at least 5 minutes (longer is fine).

Step 3: Place the lamp upside down in the ring stand so that the bulb is pointing down toward the table. Adjust the stand so that the bottom of the bulb is about 12” above the table if using a floodlight, or about 6” above the table if using the 100W light bulb.

Step 4: Place a thermometer inside the clear plastic soda pop bottle and place the bottle about 1” away from the bulb.

Step 5: Place the other thermometer about the same distance from the bulb as the thermometer under the pop bottle. If the thermometer inside the bottle is leaning against the inside of the bottle, then lean the other thermometer against something stable at about the same angle.

Step 6: Turn on the light and wait three minutes. After three minutes, lightly fan the thermometers with the newspaper. Do not fan so heavily that the thermometers move or the bottle falls over. Continue fanning for one minute.

Step 7: Turn off the light and record the temperatures of the thermometers.

Temperature under the bottle: ______º F / C (circle). Temperature outside the bottle: ______º F / C (circle). Part2: Build Your Own Planet

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.

Because there might be small differences in the thermometers, we need to swap the thermometers and repeat Steps 6 and 7 of the experiment.

Temperature under the bottle: ______º F / C (circle). Temperature outside the bottle: ______º F / C (circle).

Step 8: Add the two temperatures recorded under the bottle. Total temperature under the bottle: ______º F / C (circle).

Step 9: Add the two temperatures recorded outside the bottle. Total temperature outside of the bottle: ______º F / C (circle).

Questions: 1) Was the temperature under the bottle higher or lower than the temperature outside of the bottle? ______.

2) Which thermometer—the one outside of the bottle or the one under the bottle—represents the effect of the atmosphere?

______.

3) How does the atmosphere affect a planet’s temperature?

______.

You should have discovered that the temperature under the bottle was warmer than the temperature outside the bottle. Heat energy from the Sun bounces off a planet’s surface and radiates back into space. You were mimicking this effect when you fanned the thermometers. The bottle acted as a kind of greenhouse atmosphere around the Part2: Build Your Own Planet thermometer. It trapped the heat around the thermometer making the temperature even higher. You’ve probably felt the same effect happen if you’ve ever gotten into a car with its windows rolled up on a hot, sunny day.

The ability of an atmosphere to trap heat is called the GREENHOUSE EFFECT. Not all the gases in an atmosphere are greenhouse gases, that is, gases that trap heat. Carbon dioxide, methane, and ozone are three greenhouse gases that we have in Earth’s atmosphere, but there are others.

On Earth, nitrogen and oxygen make up 99% of the gases in our atmosphere. Neither of these gases traps heat. Most of Earth’s greenhouse effect comes from carbon dioxide and methane. But only 0.03% of our atmosphere is carbon dioxide, and methane makes up only 0.002%. Yet both of these gases have a great effect on our average surface temperature.

Check the Planet Temperature Calculator to see how important these tiny amounts of carbon dioxide and methane are in warming our planet. (www.astro.indiana.edu/~gsimonel/temperature1.html) Enter normal Earth values for MASS (1), DISTANCE (1), and BOND ALBEDO (29), but set the GREENHOUSE EFFECT to “0,” (no effect).

4) What is Earth’s average surface temperature with no GREENHOUSE EFFECT? ______º F / C (circle).

Venus has a GREENHOUSE EFFECT 200 times as powerful as Earth’s. Because of this, Venus’ average surface temperature is around 460ºC, much too hot to support life as we know it. What would Venus be like without any GREENHOUSE EFFECT? We can find out by entering Venus’ values for distance and albedo into the planet temperature program and setting its GREENHOUSE EFFECT to 0. Enter these values into the program: Part2: Build Your Own Planet

MASS: 1 DISTANCE: 0.72 BOND ALBEDO: 75 GREENHOUSE EFFECT: 0

5) What is Venus’ average surface temperature with no GREENHOUSE EFFECT?

______º F / C (circle).

6) Would Venus still be too hot to support life with no GREENHOUSE EFFECT?

______.

7) Would Venus be habitable with no GREENHOUSE EFFECT?

______. Why or why not? ______

______.

8) Now think about the average surface temperature of the planet you are exploring. Based on what you have discovered with the planet temperature program, is the average surface temperature of your planet too hot, too cold or about right? ______.

9) Based on what you now know about greenhouse effect, do you want your planet to have a strong or weak effect? ______.

Look at number 6 of the planet preference survey to find out the type of atmosphere on your planet. The thickness of the atmosphere you chose will restrict the range of numbers that you may enter for GREENHOUSE EFFECT in the planet temperature program. Part2: Build Your Own Planet

If you chose “Trace” choose a number between 0 and 0.4. If you chose “Thin” choose a number between 0.4 and 3. If you chose “Thick” choose a number between 3 and 300.

Our planet has a GREENHOUSE EFFECT of ______.