Drexel-SDP GK-12 ACTIVITY
Activity : Solar System in a BoxExploring Length Scales, Large
Numbers and Our Nearest Neighbors
Subject Area(s)
Physical Science, Chemistry, Physics and Engineering
Associated Unit
Astronomy
Associated Lesson
Activity Title
Astronomical Distance.pdf
Scale Model of the Solar System
Header
Grade Level _7-_8 (__-__)
Time Required 50 min period
Group Size 10 groups of 2
Expendable Cost per Group
Cost of clay per group is $ 4.00
Summary
Students will explore distances in our solar system by making a scale model.
Engineering Connection
Scientists and engineers use models to better understand the real world. They are best known
as representatives for physical objects, but they also help to conceptualize phenomena, systems,
processes and abstractions. By physically manipulating models scientists and engineers gain a
deeper understanding of the things they are studying. Models can be physical, like ball and stick
molecules, or mathematical. The key to using models is understanding that no matter how useful
the model is it is only approximating the real system, so there are always flaws.
Keywords
Solar system, models, astronomical unit, light year
Educational Standards
 Science: 3.4.7 D
 Math: 2.3.8.G
Pre-Requisite Knowledge
Students are expected to know how to multiply.
Learning Objectives
After this lesson, students should be able to:
 Convert from inches to centimeters

Calculate the distance in kilometers, of a planet to the sun, if given the AU.

Create a spreadsheet in Excel to calculate astronomical distances

Establish a scale based on the earth’s diameter and calculate the appropriate distances to
create a scale model of the solar system

Build a scale model of the solar system that fits in a 2 meter box.
Materials List
Each group needs:
1. Colored modeling clay
2. Metric/English ruler
3. Calculator or computer
To share with the entire class:
 none
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Introduction / Motivation
Large numbers are a difficult abstraction. Most posters and classroom models illustrate the solar
system in such a way that the distances between the planets and the relative size of the planets
are inaccurate. This is necessary because the planets are small compared to the distances between
the planets and for convenience the models are inaccurate.
The students will discover for themselves that it is not possible to build a model that satisfies the
design criteria of building a scale model of the solar system in a 2 meter box, in fact it will not fit
in the average classroom. They will have to use two different scales, one for the planets and one
for the distances between the planets to meet the 2 meter box requirement.
Vocabulary / Definitions
Word
Definition
Astronomical The average distance from the earth to the sun. 149,597,870.691 kilometers.
Unit (AU)
The AU is used to measure distances in our solar system.
Light Year
The distance light travels in one year. There are 9.4605284 x 1015 meters in 1
(LY)
light year.
Speed of
2.99792458 x 108 meters/sec
light
Procedure
Background
See attached pdf of a PowerPoint presentation. Astronomical Distances
Before the Activity
Show the student the presentation defining the terms for this activity. Pass out the activity work
sheets. Go through how to set up an Excel spread sheet, some students may not know how to
enter a formula and fill down. Also after selecting an example scale demonstrate with a meter
stick or ruler how to translate the lengths from the calculations to the ruler. For example: What
does 1.5 cm measure on a ruler? Demonstrate also how to estimate the diameter of a sphere on a
ruler.
With the Students
1. Explain how to calculate the conversions. Go through the examples on the work sheet. Ask
them to do the next problem themselves. Walk around the classroom and answer questions.
2. Have them open Excel and create a spreadsheet to do the same calculations.
3. The students should then decide on a scale (ie 1 cm = 1 earth diameter) and make scale
models of the planets. It is instructive to try several scales before deciding on the best fit for
their model.
4. Let them figure out they cannot use the same scale for the distances between the planets.
Attachments
Astronomical Distances PDF
Astronomical Distances worksheet.doc
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Safety Issues
Use non toxic clay.
Troubleshooting Tips
none
Investigating Questions
1. Explain how you determined the scale for your model? What were the design
constraints?
2. Were you able to use the same scale for the size of the planets as you used for the
distances between the planets?
3. Did you have enough material to include the Sun? Explain your answer using some of the
calculations you did?
4. What surprised you the most when making the model?
Assessment
Pre-Activity Assessment
none
Activity Embedded Assessment
Check each group’s models. Ask
Post-Activity Assessment
none
Activity Extensions
http://www.nasa.gov/topics/solarsystem/index.html
Ask the students to keep a journal of the night sky. Identify the planets and constellations.
Additional Multimedia Support
References
See attachment.
Other
Redirect URL
http://www.ioncmaste.ca/homepage/resources/web_resources/CSA_Astro9/files/html/module4/
module4.html
Owner
Drexel University GK-12 Program
Contributors
Jennifer Atchison, Dorothea Stanley
Copyright
Copyright 2008 Drexel University GK-12 Program. Reproduction permission is granted for nonprofit educational use.
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