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To boldly go where no one has gone before...Thanks to the recent exploration of space by manned and robotic spacecraft, mankind has begun to accumulate a vast wealth of knowledge on our Solar System. When trying to relate this information about our Solar System, it is often difficult to get past some erroneous assumptions on the part of students regarding the size and scale of our local neighborhood in space. Text books, limited by their size, can't possibly show the relative sizes and distances of the planets and the Sun on their pages. This, combined with the unbelievably huge numbers involved, often leaves students with mistaken perceptions of the actual relative size of the planets and the vast distances that separate them.

In this lesson, students will learn a common theory on how the Solar System was formed, the major components of the Solar System and some of their physical characteristics, and gain an understanding of the relative scale of the size and distances among the bodies of the Solar System. This lesson is to be part of a larger unit on space. Prior to this lesson, it is expected that the students have investigated the Earth-Moon system and the relationship each body has with the other (i.e., tides, phases of the Moon, some earthquakes, related folklore, months, eclipses)
ITV Series
Earth, the Environment and Beyond, #12: The Solar System
Learning Objectives
Students will be able to:
Previewing Activity Materials (for each group of four students):

Viewing Activity Materials (for each student):

Postviewing Activity Materials (for each of nine groups)

Materials (for the teacher's use in the activities)
Pre-Viewing Activities
In this activity, students will estimate the size of the Moon in relation to the Earth and construct models, from modeling clay or play-doh, to represent these estimates. They will then estimate the relative distance between the Earth and Moon. In both instances, the students will calculate what the actual relative sizes and distance should be and compare these to their estimates. Inform the students to be prepared to explain their estimates. This will help the students to understand the size and distance involved in the Earth-Moon system.

For each group of four students, provide the materials listed above under Previewing Activity Materials.

Start the activity by asking the students in each group to make a prediction on what the relative sizes of the Earth and the Moon are to each other. After several minutes for discussion, have them sketch it on a piece of paper so that everyone agrees on the group's prediction. Once a consensus has been reached within each group, instruct them to mold their models, using the clay, to the size of their drawings. Have each group explain to the rest of the class why they chose the representations they did.

When all groups have completed this task, explain that the actual diameter of the Moon is about one- fourth that of the Earth. Discuss how each group's model compares to the actual scale and have each group adjust their models to reflect the actual scale. They may use their rulers to help with this adjustment.

Next, ask each group to estimate the relative distance between the Earth and the Moon using their models. Allow several minutes for group discussion before having them display their guesses. Again, ask each group to explain their predictions to the rest of the class.

At the conclusion of the group explanations, inform the students that the actual distance between the Earth and the Moon is 30 Earth diameters! Have each group calculate, and demonstrate, this distance using their models. Rulers may be helpful here, also.
Focus Viewing
To give the students a specific responsibility while viewing, ask them, still in their groups of four, to be on the lookout for the following information, which they will need to complete their worksheets (a template of which is located at the end of this lesson plan, along with a completed teacher's answer sheet): the type of planet (terrestrial or gas giant) the distance of each planet from the Sun the number of satellites each planet has what their atmospheres are made of

Explain that they will need this information in order to do the next activity, and that the video will be shown twice so that they may gather their data.

Some of the planets are missing one or more of these pieces of information in the video. It is up to each group to research this missing information once they have completed their worksheets. In fact, very little information is given on Pluto in the video. Encyclopedias, whether in print or on cd-rom, would be a good place to start. One suggestion for each group may be to assign one person within the group the responsibility for gathering a specific piece of information. For example: one person will write down the type of planet; another writes down the distances; another writes down the number of satellites; and the last will write down what's in the atmospheres.

Make copies of the attached worksheets entitled "Solar System Data Worksheet" and distribute to each student. An overhead transparency made from the same templates will help during post- viewing discussion.

Instruct students to look up the definition of words in a dictionary and complete each word before proceeding to the video.
Viewing Activities
Start the video at the part of the show titled "Origins of the Solar System."

PAUSE video when narrator says, "One of the most widely accepted theories states that it began as a mass of swirling clouds and gases that rotated for several hundred million years."

Ask: "What is a theory? Is it stating a fact?" (A theory is an educated guess that is a possible explanation for something. Therefore it is not a fact.) Solicit some theories that have been proven wrong (i.e., that the Earth is flat; the Earth is the center of the universe; that everything in the sky revolves around us; the Moon is made of cheese).

RESUME video.

PAUSE video when narrator defines "terrestrial." Have students repeat this back to you and have them identify which planets are terrestrial. (Terrestrial means Earth-like. The terrestrial planets have metal cores and consist of Mercury, Venus, Earth and Mars.) Instruct the students to label those planets with a "T" on the worksheet. Replay that segment if necessary.

RESUME video.

PAUSE video at SCIFAX question: "Are asteroids of value to the human race?" before the answer is given. Solicit responses and discuss with the class.

RESUME video.

PAUSE video when narrator identifies the gas planets. Have students label the gas planets with a "G" on their worksheets. (The gas planets are Jupiter, Saturn, Uranus and Neptune.) Replay that segment if necessary.

RESUME video.

PAUSE video at SCIFAX question: "How massive are comets?" before the answer is given. Solicit responses and discuss with the class.

RESUME video.

STOP video at the title "The Future of the Solar System."

REWIND video back to the title "Inside the Solar System" and replay once more so that students can gather missed information or verify the answers on their worksheets. Allow ample time for each group to research any missing data and share its information among its members. Once this is completed, show an overhead transparency of the same worksheet and complete it as a class. This is to verify that everyone has the same information.
Post-Viewing Activities
Tell students they are now going to do an activity which will illustrate what they have seen on the video. This activity will consist of two parts:
1. constructing the nine major planets to a scale of relative size, and
2. placing the planets in the correct order outward from the Sun and spaced apart in a proper scale.

The two scales being used here are not the same. This activity is designed so that it can be done indoors or outside. You will be provided with relative distances so that you can fit it in most any available large space whether it's a hallway, a gymnasium or your schoolyard. This means, of course, that you will have to calculate their positions, but this makes an excellent student activity.

Materials needed for these activities by each group are listed in the Postviewing Activity Materials section of this lesson plan.

Constructing the nine major planets
1. Have the class identify the nine major planets in our Solar System. Divide the class into nine groups (one for each major planet).

2. Explain to the students that they are going to create a scale model of the Solar System. Lead a short discussion on the usefulness of a scale model in astronomy. (Things in space are too large and far away for direct study.)

3. On an index card, write down the name of a planet; its diameter (in miles); and its size in the model. This information is listed after step 7 below. Walk around to each group and assign them their planet. If you have a particular group that needs to be challenged, assign them Pluto. They will have to do the most research to gather all necessary data. Have each group keep their planet a secret from the other groups. Secrecy adds a touch of mystery as well as allowing the students to predict the sizes of the planets later on.

4. Ask each group to cut out their planets using the data on the index card. They will need to perform a quick calculation first. (See worksheet.) Those groups with the smaller planets may want to tape their planets to an index card to make it easier to see. 5. Write the numbers 1 through 9 on the chalkboard and have groups randomly place their planets, using masking tape, under one of these numbers. Random placement lets the students predict which planet is which.

6. Survey the class for their guesses as to which planet is which. Allow time for ample discussion and have students refer to their worksheets for assistance until the correct labels are made.

7. Ask students what major part of the Solar System is missing. Upon their responding "the Sun" (hopefully!), take out your model of the sun and discuss the size of the planets in relation to the Sun. Inform the students that the Sun contains 99% of all the matter in the Solar System. This illustration should drive this point home. You may want to tape the planets to the Sun for effect.

The approximate sizes of the Sun and planets should turn out as follows:

Object Diameter (miles) Model size
Sun 900,000 11 1/2 FEET!
Mercury 3,000 1/2 inch
Venus 8,750 1 1/4 inches
Earth 8,750 1 1/4 inches
Mars 4,000 2/3 inch
Jupiter 86,000 13 1/4 inches
Saturn 72,000 11 inches
Uranus 30,000 5 inches
Neptune 30,000 5 inches
Pluto 1,400 1/4 inch

Placing the planets on a proper scale
This exercise is to be customized for the space available to you. Below are instructions, including formulas, to help you achieve this.
1. Astronomers use a unit of measure called an Astronomical Unit (AU) to represent the average distance between the Earth and the Sun. Therefore, 1 AU equals the distance between the Earth and Sun. The distances of all of the other bodies in the Solar System from the Sun can be measured in AU's, and they are as follows:
Planet Distance (in AU's)
Mercury .33
Venus .67
Earth 1.0
Mars 1.5
Jupiter 5.0
Saturn 10.0
Uranus 19.0
Neptune 30.0
Pluto 40.0

2. Now your class needs to measure the distance available to it, whether it's a gymnasium or a hallway (bends and turns are ok). If you have enough space outside available to you, then the sky's the limit, so to speak. The larger the space you can find, the better the effect. Take that distance, subtract 11.5 feet for the diameter of the Sun (or 5.75 feet if you use half a Sun). Divide this difference by 40 (because when Pluto is at its farthest distance from the Sun, it is 40 AU's from the Sun). This distance equals 1 AU.

3. Have each group calculate the approximate distance each planet should be located from the Sun in your model by multiplying the AU's for each planet by the figure calculated in step 2.

4. Have each group develop a statistic sheet from the Planetary Information worksheet completed while viewing the video, and from other sources, to be posted with their planet.

5. Before starting on your class walk, ask students to guess which planet is the halfway point between the Sun and Pluto at its farthest point and to keep their guesses in mind as they do the walk. Walk with the class through your available space, starting at the Sun, and have one representative from each planetary group place their planet in the appropriate place. At each placing of a planet, have a student from that group recite the characteristics of that planet from the statistic sheet prepared in step 4 above. After Uranus (the correct pronunciation of which is "yurinis" not the often mistaken match to a part of the anatomy which conjures giggles each time it is spoken), inform the students that they are now at the halfway point between the Sun and Pluto. If it is possible, instruct the students to look back towards where they placed the Sun so that they might grasp the extreme distances involved here.

6. Invite other groups ( i.e., other classes, administration, school board, community visitors) to walk through your Solar System, perhaps with one of your students as a guide.

7. Video tape a tour of your model for students to keep, for viewing at the end of this unit and at the end of the year.
Action Plan
Visit a planetarium, or have a traveling planetarium visit your school (check with local planetariums and your Yellow Pages).

Contact your local astronomy club and invite a guest speaker. These local clubs are often very accommodating. Again, consult with your local planetarium for this information.

Contact your regional NASA educational resource center for free, or low cost, information and materials available to educators.

Watch, or more likely tape, a five-minute program called Star Hustler, hosted by Jack Horkheimer, for weekly updates on happenings in the heavens that can be observed by the naked eye. These happenings include the positions of the planets, phases of the moon, meteor showers and constellations, among other things. Check your local PBS schedule for viewing times.
Mathematics: Each planet has a different mass than that of Earth. This means each planet has a different gravitational attraction. Research these masses and have the students calculate their weights for each planet.

Art: Have students design and/or construct an environment for a manned mission to their planet, or a satellite of their planet (manmade or natural). Social Studies: Research the history of the exploration of the Solar System, both manned and unmanned. Refer back to your Solar System model to see how little man has really ventured out into space!

Language Arts: Read The Magic Schoolbus in the Solar System as a class. Also have each group write a short paper describing everything from the discovery of the planet, its physical characteristics, all facts and figures gathered in the two activities performed above, the mythology behind the planet's name and any astrological significance associated with it.

Master Teacher: Daniel E. Reidy
Newfound Memorial Middle School, Bristol, NH

This Master Teacher would like to acknowledge John G. Radzilowicz and Jan Derby, of the Christa McAuliffe Planetarium in Concord, NH, for their contribution to this lesson plan.


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