Lesson Plan
Lesson Title / Solar System on a Map/Solar System Scavenger Hunt
Grade Level
State Indicator(s)
Goals and Objectives for Student Learning / Students will get a better handle on exactly how big the solar system really is by scaling down the size of the solar system to the same scale as a map of a familiar place (your school, Columbus, Ohio, etc.).
In the process, students will practice crucial math and science skills such as performing unit conversions (i.e., algebra) and map reading.
Diversity
Teaching Method / Guided Inquiry
Learning Activities / Science Introduction:
Space is REALLY big, and it is often hard for students (or even teachers) to grasp just HOW big space, and even the solar system, actually is. In this lesson, students will get a handle on how big the solar system is by making a scaled model, based on a reference frame they are familiar with, such as their school building, the city of Columbus, or the state of Ohio.
The distances of the planets/dwarf planet (so we can include Pluto, hence forth simply called a planet for simplicity1) from the sun are the following (here, distances have been put in units of both kilometers and astronomical units, AU, where 1 AU is defined as the average distance between the earth and the sun):
Sun to Mercury: 0.387 AU = 57,900,000 km
Sun to Venus: 0.723 AU = 108,200,000 km
Sun to Earth: 1.000 AU = 149,600,000 km
Sun to Mars: 1.524 AU = 227,900,000 km
Sun to Jupiter: 5.203 AU = 778,300,000 km
Sun to Saturn: 9.555 AU = 1,429,000,000 km
Sun to Uranus: 19.22 AU = 2,875,000,000 km
Sun to Neptune: 30.11 AU = 4,504,000,000 km
Sun to Pluto: 39.54 AU = 5,916,000,000 km
Note that these are the ‘average’ distances. The planets orbit the sun in elliptical orbits and so are not actually the same distance from the sun at all times. However, most of the orbits are close enough to circular that just using a circle is a good approximation, particularly for a lesson such as this.
By choosing a scale factor, say 1 meter on school grounds = 10,000,000 km in the Solar System, then you can apply this scale factor to all the Sun-planet distances to get the distance each planet would be from a model of the sun placed, say, in your classroom:
Sun to Mercury: 5.79 meters = 19.0 feet
Sun to Venus: 10.82 m = 35.5 ft
Sun to Earth: 14.96 m = 49.1 ft
Sun to Mars: 22.79 m = 74.8 ft
Sun to Jupiter: 77.83 m = 255 ft
Sun to Saturn: 142.9 m = 469 ft
Sun to Uranus: 287.5 m = 943 ft
Sun to Neptune: 450.4 m = 1478 ft
Sun to Pluto: 591.6 m = 1941 ft
This conversion can be made for any size scale factor you choose. Students will then have to reproduce these distances based on the map that you give with the additional scale given in the legend of the map (e.g., 1 inch on the map = 10 ft on school grounds. The goal is to try to find the place on the map where each planet is located, compared to some reference point where the Sun is located.
Teacher Preparation Procedure:
1.)  Determine what map/size scale you wish to use for this activity.
2.)  Develop an appropriate solar system-to-map scale factor that makes it possible to fit the entire solar system on the map (Hint: Start by basing your scale factor on the orbit of Pluto so that you know that Pluto’s orbit will fit on the map, and work your way inward from there).
3.)  Determine the distance to all the planets from the central region on the map you’ve chosen for the sun by first applying your scale factor from the solar system to the actual size scale of your school/Columbus/whatever you’ve chosen and then applying the scale of the map from the map legend to get your planetary distances in map units. Example:
a.) (True distance from Sun to Pluto, km) * (solar system to school campus scale factor) = (distance to Pluto in physical units on the school campus)
In other words:
5,916,000,000 km * 1 meter / 10,000,000 km = 591.6 meters, physical distance between Pluto and the sun on campus.
b.) Distance to Pluto on campus * legend scale on map = map distance of Pluto from sun, so
591.6 meters * 1 cm/1.5 meters = 394.4 cm on the map between the sun and Pluto.
4.)  Once you’ve determined an appropriate scale factor as well as the scale factor of the map you’re using, determine the location of each of the planetary orbits on the map by measuring the radius of the orbit from the distance between the sun and each planet in map units, and then drawing a circle of this radius around the model sun in the center of the map.
5.)  “Place” each planet somewhere within the school based on a room that the planet’s orbit enters from your scaled map drawing.
Student Procedure:
This is much the same as the teachers, except the teacher will provide the students with a blank map, with only the location of the sun drawn (make sure the map contains a legend with the map scale units), in addition to the scale unit they should use for mapping their solar system onto the map (i.e., the 1 meter = 10,000,000 km scale factor). The students will then need to use this information to map out their solar system and guess the locations within the school that you’ve ‘placed’ the planets (for real scavenger hunt alternative, see Supplements below).
1 In 2006, the International Astronomical Union (IAU) set the definition of a “planet” to be a celestial body in the Solar System that satisfies all three of the following criteria: (1) it must be in orbit around the Sun, (2) it must have sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and (3) it must have “cleared the neighborhood” around its orbit (i.e., there are no other bodies of comparable size other than its satellites in its orbital zone). Under this definition, Pluto is now classified as a “dwarf planet” because it only satisfies the 1st and 2nd criteria (it shares its orbital neighborhood with Kuiper belt objects, such as the “Plutinos”).
Materials / Map (with scale)
Calculator
Ruler
Compass (for drawing circles, optional; alternative: two pencils and a string)
Set of clues (for Scavenger Hunt variation, below)
Supplements / Solar System Scavenger Hunt:
Turn this lesson into a real scavenger hunt with clues and prizes: If it is possible for students to actually move about the school grounds (inside and/or outside), a fun supplement to this lesson is to actually make either signs or models (e.g., think Styrofoam balls) of the planets, and ‘hide’ them along their orbits in your scaled model of your school grounds. Then make clues for each planet, so that once your students have their scaled model drawn on their map, they can get a copy of the clues. Based on the clues and the areas of the map through which their orbits pass, they must go find the true location of the planets, where you’ve hidden them.
If you cannot allow your students to actually roam the halls and grounds of your school, a more stationary variation is to use a geographical map, of say, Columbus, Ohio, or even the U.S. and make your clues word puzzles, or other types of clues to get to them guess the intersection or park, etc., where you have “hidden” the planet. This makes the lesson more interdisciplinary as well, including geographical facts they may need to know in order to determine where you have “hidden” the planets.
Hidden Scale factor:
If you are using the stationary, map, approach, reverse the order of the information you give them, and instead, start by giving them the scavenger hunt word clues. By determining the location of each planet away from the sun, make them calculate the scale factor you assumed to place the planets in these locations.
References / Lesson by Kelly Denney, The Ohio State University