Planets Made Real - Creating Size and Distance Scale of Planets in the Student's Community

Sam Greene
Community Christian School
Willmar, MN 56201
To my knowledge, an original activity.
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Students select a marble from a bowl of many of different sizes. This represents model Earth. Students are to use this model and planet information of size and distance to tabulate and record model size and distance of the solar system. Students will create cutout models of planets to display in class, and the ellipses of the planets on city and county maps with the sun located at the site of the school. Questions for further study will develop when the students see their solar system model spread out over the county.

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Learning Goals

1) This activity is designed for students to find proportions and record them in an organized, understandable format.

2) This activity is designed for students to use tabulated data to create a solar system model.

3) Students will compare their perceptions on their beliefs about the solar system before and after the investigation.

-Mind model

Context for Use

"Planets Made Real" can be accomplished in a little more than two class periods of 45 minutes each. Division of labor is important for this to be achieved. Small groups of three students are able to organize tabulated data in an understandable format, make scale model planet cutouts, and record planet scale model orbits on city and county maps.
Proportions are usually covered in the sixth grade; however, a review of the skill may be necessary either by the math or science teacher. Students are usually taught proportions out of context and never get to use it in a real life situation. Once they learn how it is done, proportion will become a handy life-skill tool to be adapted to other areas of their life.

Description and Teaching Materials

Before the end of day one, students are grouped into 3's for the following day. A member of each group selects a marble out of a bowl. The groups are told that the selected marble is the Earth. Their assignment is to use this marble to tabulate a proportional sun for class the next day.
At the beginning of class on day two, each group is given a city and county map. The groups mark the approximate location of the school on each map. The school will be the location of the sun or the center of the model of the solar system. Students are also asked to predict and mark where the other seven planets and dwarf planet Pluto would be located on the maps using the school as the sun.
Students are asked to tabulate a scale model of our solar system using the Earth's size represented with the marble. Their end products will be their data organized in an understandable, word processed format, scale planet cutouts, and the scale ellipses of the planets on the given maps.
Several colors of butcher paper, scissors, compasses, meter sticks, and computers should be made available in the classroom. Students will display their planet cutouts on the class walls. Their maps and data collection sheets will be used in class discussion.
Since the original marbles are different sizes, the calculations will not be the same between the groups. Students will compare their cutouts to the neighboring groups. The class will compare the different group's proportions of the distances from the data sheets and maps.
Question always arise on how astronomers found the distant planets. This opens the new round of inquiry. Teacher Made - Student Filled (Microsoft Word 40kB Aug20 08) Evaluation Rubric ( 25kB Aug20 08)

Teaching Notes and Tips

Proportions are not that difficult to find; however, some students may have a time trying to calculate them if they do not understand. Using the format below, students will be able to complete the computation in time to finish the rest of the project.
If the student multiples the real diameter of any planet (say, Mars) by the model diameter of Earth (or the diameter of the marble) and divides that number by the real diameter of Earth, the missing variable X will be the model diameter of the planet (Mars)
If the student multiples the model diameter of any planet (say, Mars) by the real distance of Mars to the sun and divides that number by the real diameter of Mars, the missing variable Y will be the model distance of the planet (Mars) to the sun.
In past years the students were given the same size marble, a data collection sheet, and a set of directions on how to come up with the answers. I taught the math and spoon feed them with skills that they should have but are not using. Everything is doable according to the school's curriculum. They should have no problems adjusting to inquiry.


Small groups of three students are responsible for organizing tabulated data in an understandable format, making scale model planet cutouts, and recording planet scale model ellipses on city and county maps. A quiz and the students' perceptions of our solar system will also be evaluated. (See Attachments for rubric)



References and Resources