Education and
Public Engagement
at the Lunar and Planetary Institute
Explore! Jupiter's Family Secrets

Solar System in My Neighborhood


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 Jupiter to set the stage for further 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?


For each group of 20 to 30 children:

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

For each child:

For the facilitator:


Quadrants map

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.



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.

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.

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

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.

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.

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:

5. Introduce the idea of scale with a discussion.

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.

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.


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

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!

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.

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!