Lunar and Planetary Institute

Our Family of Planets: Solar System in My Neighborhood
EXPLORE! Solar System

# Solar System in My Neighborhood

## Overview

In this 1-hour activity, children, ages 9 to 13, shrink the scale of the vast solar system to the size of their neighborhood. They are challenged to consider not only the traditional "planets," but also some of the smaller objects orbiting the Sun. Children compare the relative sizes of scale models of the planets, two dwarf planets, and a comet as represented by fruits and other foods. They determine the spacing between the scaled planets on a map of the neighborhood and relate those distances to familiar landmarks. This indoor activity may be used in addition to, or in place of, the outdoor scale model explored in Jump to Jupiterto set the stage for further Big Kid on the Block activities.

The scale of this activity is quite large — so large that it fills an entire neighborhood! The advantage of this scale is that the children can see and compare even tiny "Pluto" and "Eris" to the gigantic "Jupiter" and even larger "Sun." Unfortunately, the distances between the model planets are too large demonstrate in typical library or school grounds. The activity Jump to Jupiter presents the solar system at a smaller scale so that the children may lay out several or all the planets at the correct distances, but the planets must be represented by tiny seeds and even pepper flakes. Use one or both of these activities to allow the children to experience both the sizes and distances of the planets in our solar system.

This series is appropriate for children ages 10 to 13.

## What's the Point?

• The solar system has eight planets, an asteroid belt, several dwarf planets, and numerous small bodies such as comets in orbit around the Sun.
• The four inner terrestrial planets are small compared to the four outer giant planets.
• Planets have some similarities and many differences.
• The distance between planetary orbits is large compared to their sizes.
• Models can help us comprehend large-scale spatial relationships.

## Materials

For each group of 20 to 30 children:

• One of each of the following fruits and other foods* (listed from largest to smallest):
• (55"–wide) giant pumpkin

OR

• (55"–wide) model pumpkin, made from

• 1 Halloween orange pumpkin garbage bag, which is available from retailers    such as Amazon.com
• Packing peanuts or pillows to fill the bag

• (5 1/2"–wide) large mango or potato
• (4 1/2"–wide) large orange or cantaloupe or coconut
• (2”–wide) plum
• (2"–wide) kiwi or lime
• (1/2"–wide) small grape
• (1/2"–wide) large blueberry
• (1/4"–wide) pea or navy bean
• (1/5"–long) uncooked orzo pasta
• (3/32"–wide) grain of uncooked rice
• (1/16"–wide) grain of uncooked rice
• (1/64"–wide) poppy seed
• Measuring tape (to measure a distance of 190 feet)
• Coloring supplies, including markers and colored pencils
• Optional: 1 set of Our Solar System lithographs (NASA educational product number LS–2001–08–002–HQ), preferably double–sided and in color
• 1 (22" x 32" or larger) neighborhood map, extending to 6 miles from your geographic location, prepared as described under "Preparation" using either a photocopier and a detailed local map or mapping software and a printer
• 11 (20") strings
• Ruler
• Tape
• 11 coffee stirrers
• Planet Labels (Image Credits)
• Optional: Access to the online song “11 Planets” by Lisa Loeb
• A large area where the children can model the orbit of Mercury around the Sun (perhaps outdoors for this portion of the activity), investigate the fruit, and gather around the map to plot their team’s planet
• A large wall, table, or floor space for posting or laying the map down

*These foods may be used again in the activity Dunking the Planets.

For each child:

For the facilitator:

• Background information:

## Preparation

• Review the complete background information.
• Use the Solar System in My Neighborhood: Planet Sizes and Distances to select appropriate fruits and other foods* to represent the planets, where they are listed in order from smallest to largest to allow more room for substitution/creativity. For example, you may choose to use a small grape for the Earth and a large blueberry for Venus, or vice versa, but "Earth" should be slightly larger than "Venus."
• If you are using a large pumpkin to represent the Sun, have an adult carry it during the activity. If you are using a Halloween orange pumpkin garbage bag, fill it with light–weight materials such as packing peanuts or pillows.
• Provide a large indoor or outdoor space (measuring at least 190 feet wide) where the children can model the orbit of Mercury around the Sun. Provide an indoor space where the children may work in teams and draw on a common map.
• Cut out the Planet Labels and tape them to one end of each coffee stirrer. These flags will be taped to the neighborhood map.
• Prepare a large neighborhood map either by photocopying a printed map or by printing sections from mapping software. Or, consider having the map professionally enlarged and laminated for long–term use. Ensure that the map is very detailed and large enough to show small distances (just 190 feet or 58 meters to "Mercury") and large distances (nearly 4 miles or over 6 kilometers to "Pluto").
• To create a map using a photocopier, first make a copy of your area from a AAA or Key Maps, Inc. map and, if necessary, mark the scale on the copy so that it is enlarged along with the map. Offer the scale in both metric and English units. First, make a copy of your neighborhood, extending to 6 miles from your geographic location, and the map's scale. Cut the map into quadrants and enlarge each section, along with the scale, onto 11" x 17" paper.Tape the quadrants together, with your location near the center.

 If using a copier, enlarge the four quadrants of your neighborhood from a detailed local map.Tape together the 11"x17" quadrants to create one large 22" x 34" map. The map should have a scale of about 5 inches:1 mile and the children must be able to plot the distance to the dwarf planet Pluto, nearly 4 miles away from your location.
• You may also create a map with mapping software such as Google Earth — and invite the children to assemble the various printed pages into a large map, much like a gigantic puzzle of their neighborhood! Select sections of the map near your location up to 6 miles away and print them. Be sure to keep all of the sections at the same scale — without "zooming" in or out — as you work.

## Activity

1. Present the fruits and other foods to the children and explain that you will use them to create a scale model of the solar system.

• What's a model?

We use models to help us represent objects and systems so that we can study and understand them more easily. By "a scale model" in this case, we mean a model that has smaller parts but parts that are relatively the same size and distance to each other as the real planets, dwarf planets, and asteroid belt, and Sun are.

• What might the fruit and other foods represent in a model of our solar system? The children may mention planets. Some children may suggest the asteroid belt.
• What are the planets in the solar system?
Starting with those closest to the Sun, the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
• Which fruit might be the planet Mercury? Jupiter? (etc.)

As the children answer, have them take their "planets" and stand at the front of the room.

• Where is the asteroid belt? Between the orbits of Mars and Jupiter.
• Pluto is no longer called a planet. What is Pluto's new title? Dwarf planet

Have a child take the grain of rice to the front of the room.

Facilitator's Note: Pluto didn't fall off the map when the International Astronomical Union (IAU) changed our definition of the word "planet" in 2006. On the contrary, Pluto joined a whole new class of objects called "dwarf planets." Newly discovered Haumea, Makemake, and Eris are simply too different from massive gaseous Jupiter or rocky Mercury to be called by the same name. The search for these bodies is one of the hottest topics in astronomy.

Dwarf planets often have enough gravitational clout to hold on to a moon, but not enough to keep a steady orbit and a path clear of debris. Unlike comets and many asteroids, dwarf planets collected enough mass in their infancy to form a fairly spherical shape.

• Can anyone name any other dwarf planets? Ceres (in the asteroid belt) and Eris are represented by fruit in this activity. Haumea and Makemake are two dwarf planets recently given names by the International Astronomical Union (IAU), and others are expected to be announced in the coming years.
• We are sometimes able to see balls of ice and dirt and their long tails in our night sky, which are named after their discoverers, like Haley. What are these called and how big would they be at these scale? Comets.

Compared to the other "planets," comets and asteroids are too small to be represented by a fruit — they are too small to even see with the naked eye!

2. As a group, have the children work to arrange the children holding the fruit in the proper order, starting with the planet/fruit closest to the Sun and working out to the planet/fruit farthest from the Sun.

• What planet is closest to the Sun? Mercury.
• What comes next? Venus; then Earth, Mars, Ceres and other asteroids in the asteroid belt, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, (Haumea), (Makemake), and Eris.

3. Optional: Present or create a mnemonic device to help the children remember the order of the planets and dwarf planets. For instance, they might listen to the song "11 Planets" by Lisa Loeb and hold up their fruits as they are named in the song. Note that the search for more dwarf planets is underway, and it may not be possible to capture all their names with one phrase! Challenge the children to create their own mnemonic for the planets alone or all the planets and dwarf planets identified in the solar system to date.

4. Ask the children questions that promote observation and comparison:

• What are the largest objects? Smallest? After the Sun, Jupiter is the largest. All the dwarf planets are tiny in this scale; Eris is slightly larger than Pluto. Ceres and Comet Halley are too small to even see.
• Most nearly the size of Earth? Venus.
• What lies between the planets? SPACE! There is mostly space between the planets as well as some dust, comet debris, asteroids, the solar wind, and a few spacecraft made by humans.
• What is similar about all the planets? All planets are spherical, spin on their axes, and orbit our Sun in the same direction.
• What are some main differences between the planets? The children will have many ideas! Some of these might be included: Because of their distance from our Sun, the surfaces of the inner planets are warmer than the outer planets. Four planets are solid and four— Saturn, Jupiter, Uranus and Neptune — are made of gas. The gaseous planets have rings. The atmospheres of every planet are different. Mercury and Pluto each have essentially no atmosphere and the gaseous planets are nearly all atmosphere. The atmospheres of Venus, Earth, and Mars are different in their densities and compositions.
• What surprises you most about the relative sizes of the planets? The gaseous planets are, as a group, large — giants, even! — compared to the inner planets. Jupiter is small compared to the Sun — one-tenth its size. However, it is still ten times wider than Earth!

5. Introduce the idea of scale with a discussion.

• How far do you live from here? The answers will vary and may include blocks, miles, or drive-time as units of measure.
• How far is the capitol city (or some other major landmark) from here?
• How far away is it from Earth to the Sun? To another planet?
• How far away would we have to place our fruit "planets" to make the distances between them to scale?  How far would Earth be from our Sun? How far would the dwarf planet Pluto be?

Estimating is a way to engage the children. Reassure them that this estimate is just guessing and that you are not expecting anyone to know answers to questions for which they do not have any experience. You may need to remind the children that scale involves showing size and distance relationships accurately.

Explain that our fruit "planets" are 1 billion times smaller than the actual planets. For example, it would take 1 billion grape-sized "Earths," placed side-by-side, to equal the actual diameter of Earth.

6. If necessary, temporarily move to a larger space to model the orbit of Mercury around the Sun. Invite a child to hold the pumpkin "Sun'' at one location and use the measuring tape to place another child, holding the orzo pasta "Mercury," 190 feet (58 meters) away. Ask the child to walk in a counterclockwise circle around the pumpkin.

• Where would the next planet (Venus) be placed?
• How many orbits would fit in the space?

Explain that the solar system model would take up your entire neighborhood!

7. Explain that they will create a scale model of the solar system by drawing the orbits on a map of the neighborhood. Hang the neighborhood map in a central location on a wall, table, or the floorwhere it is accessible to all. Tape the Sun label to your location. Together, draw the orbit of Mercury on the map as an example of how to proceed with the other solar system objects. Use the map's scale to mark off units of measure on a piece of string. Ask the children to identify Mercury's scaled distance from the Sun by looking at their journals. Grasp one end of the string, and using the distance markings, measure Mercury's distance of 190 feet (58 meters). Tie a pencil to the string at that length and use it as a drawing compass to create Mercury's orbit around the Sun label on the map.

Facilitator's Note:The four inner planets are very close to each other and the children will need to estimate carefully to determine the orbits for Venus, Earth, and Mars. Invite them to use Mercury's orbit as a guide. Venus is about twice as far from the Sun as Mercury; Earth is about three times; and Mars is a little over four times as far. Ask them to mentally divide their 1-mile scale into 100 pieces. Mercury's orbit measures only four of those pieces from the Sun. Venus is only about seven of those pieces from the Sun. How do these measurements compare to their estimates based on two, three, or four times the radius of Mercury's orbit?

8. Together, place the planets in the context of your neighborhood! If possible, divide the children into ten teams of two to three and provide each with one of the Planet Labels and a string. Invite the teams to determine how far away their planet's fruit representative is from your location on the map using their strings. Taking turns at the map, use the strings to draw circular paths for each planet, with your location as the center (i.e., the Sun). Comet Haley's orbit can be drawn as an oval shape using the closest and furthest distances. Identify a landmark along that orbit (e.g. a school, grocery store, or child's house). Ask the children to record the name of the landmark, along with the type of food representing it, on the planet label and tape the label at that location.

9. Invite the children to draw a map of their neighborhood and place the planets at their landmarks in their journals.

## Conclusion

Help the children visualize the vast scale of our solar system by comparing it to the fruit and its placement on your neighborhood map.

• In our scale model of the solar system, how far away are the planets? What landmark did you identify for each one? At this scale, Mercury is an uncooked orzo pasta as far away as the end of the block; Venus is a large blueberry at Susan's house; etc.
• Would you walk there or would you ride in a car or bus? Mercury is less than a block away; and even Venus, Earth, and Mars are within walking distance of the Sun at your location. Jupiter is about a 1/2 mile away, and Saturn nearly one mile away. Uranus, Neptune, and Pluto are all much further away. Comet Halley's orbit takes it almost to the orbit of Pluto.
• What do you notice about the distances from the Sun to the inner planets versus the distance to the outer planets? The inner terrestrial planets — Earth, Mercury, Mars, and Venus — are much closer together. The giant planets get farther and farther apart.

The inner planets are clustered near the Sun, and the outer planets are really far away. All the planets are tiny compared to the space between them!

• How long do you think it would it take a spacecraft to get to these other planets? Accept all answers before providing more information.

Part of this answer depends on the type of spacecraft and if it is doing other things like circling other planets. In general, if it was possible for a spacecraft to fly directly to Mercury, it would take it about 5 1/2 months to get there if it was going in a straight shot. The MESSENGER spacecraft, launched in 2004, arrived at Mercury in 2011; MESSENGER had several flybys of other planets to help it slow down so that it was able to go into orbit around Mercury. New Horizons, launched in 2006, is expected to reach the dwarf planet Pluto at the "other end" of our solar system in 2015! Due to a gravitational assist from Jupiter, New Horizon’s trip has been shortened by three years. In 2016, the Juno spacecraft will arrive at Jupiter. Juno launched in 2011, and like MESSENGER, it will have a flyby that slings it past Earth (in 2013) on its way to the giant planet.

• Are the planets in a straight line, like we sometimes see them presented in pictures? No!

Remind the children that the planets are in motion as they orbit the Sun. Only rarely do several planets "line up."

If possible, build on the children's knowledge by offering them a future Jupiter's Family Secrets activity. Invite the children to investigate further with these fruits and other foods in the activity Dunking the Planets to determine which of the real planets would float in a cosmic-sized bathtub!