Name: ____________________________________ Period: _______ Date: _________________________
Class Model of the Solar System Lab
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Introduction
It is easy to flip to the index of an astronomy textbook to discover that, say, the Sun lies 150 million kilometers away
from Earth. It is far more difficult (if not impossible), however, to picture this distance in the human mind. In this exercise,
we will learn to access the often unpalatable distances encountered in astronomy by simply scaling the huge distances
to more recognizable, pedestrian numbers. So long as every distance within the system of interest is scaled by the
same factor, we retain meaningful information about relative distances between objects. This is exactly the same
principle employed by map makers so that they can fit Texas, for example, onto a turnable page.
Pre Lab Questions
1. What is an AU? How is it measured?
2. How can making a scale model of something really large help you understand distances better?
3. What is the difference between a radius and a diameter?
Table 1 gives current measurements for the actual sizes and orbital distances (distance from the sun to the planet) of
the planets. For moons, distance is measured in Km and needs to be converted to AU. 1 AU in KM = 149,598,000
kilometers
Table 1: Measured Astronomical Distances in Solar System (*KBO radii are not well known)
Object
Radius (km)
in scientific
notation
Sun
Radius (km) in expanded
form
Distance
from the
sun in AU
Distance from the planet in Km
6.96 x 10^5
--
--
Mercury
2.44 x 10^3
0.39 AU
Venus
6.05 x 10^3
0.723 AU
Earth
6.38 x 10^3
1 AU
Moon
1.74 X 10^3
Mars
3.40 X 10^3
1.524 AU
Jupiter
7.14 X 10^4
5.203 AU
Io
1.82 X 10^3
384,400 km= ______________
AU
421,700 km= ______________
AU
Ganymede
2.63 x 10^3
1,070,000km=_____________ AU
Saturn
6.03 x 10^4
Titan
2.58 x 10^3
Uranus
2.56 x 10^4
19.18 AU
Neptune
2.43 x 10^4
30.06 AU
Pluto
1.16 x 10^3
39.53 AU
Charon
6.35 x 10^2
9.539 AU
1,220,000km=_____________ AU
196,000km= ______________ AU
Creating a Scale
As you can see, even when expressed in one of the largest units (km) used to describe Earthbound
distances, the sizes of and distances to the planets require numbers raised to large powers of ten. In order to
fully appreciate the relative sizes and distances within the solar system, it is necessary to scale these
numbers down to values small enough so that we can "see" them in terms of more familiar distances. We
can accomplish this by dividing every number in Table 1 by some constant scale value.
Our sun's real radius is ____________km and the small sun I am creating for you has a radius of
_______cm. To calculate the constant for how many km 1 cm will represent in our model we can set up some
ratios and cross multiply.
______________________ = ______________________
So that…
1 cm = ____________________ km
make conversions.
this will be the constant you can use in teh following equations to
Project Instructions
As a class, we will be creating a scale model of the solar system. Each pair of students or individual students
will do the following calculations and then focus on a specific planet (and its moons if applicable). As a pair,
you will create your planet to scale according to your calculations and create a bright paper-sized “poster” to
educate other students about your planet. They will go up in the hallway at the correct distance apart from
each other to provide a scale model of the solar system.
Use the scale factors to calculate the size of your object and the distance of the object from the Sun (round
two decimal digits). Fill in these values in table 2.
- The formula for the scale size planet: radius of planet (km) / constant (km) = the number of cm your
planet's radius should be. This will also work for moon sizes.
The formula for distance from the sun to the planet: 1 AU = 1 Meter
Table 2
Object
Radius to scale (cm)
Distance to the sun (m)
Sun
109 cm
---
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Moons
Moon
Io
Ganymede
Titan
Charon
On your “posters” you should include: All of this needs to be easy to read and understand as well as colorful
and fun to look at.
○ The name of your planet (assigned
○ Actual measurements (distance to
on board))
sun, and moons’ distances to
○ Scale “planet” showing the size of
planet)
your planet according to our scale
○ Length of a day
○ Any moons
○ Length of a year
○
Three other facts you would like to
share about your plant
Individual Post-lab questions. These are to be done on your own and in complete sentences.
1. Look at all the pictures of the planets, and at table 2. Are all the pictures the right size?
2. Can you tell the difference between Jupiter and Neptune from the pictures? How about Neptune and
Uranus? Can you tell the difference between Earth and Mars? Explain your answers.
3. How does the spacing of the Kuiper Belt Objects (Pluto and Charon) compare to the spacing of the
Jovian planets and Terrestrial planets?
4.
Of the planets who had moons listed, which one has the farthest moon from the planet? Which one is
the closest? Is there a big difference between terrestrial and jovian?
5. Who was your partner? Did they assist with the project, or only write things down if you did? Were
they willing to assist with the poster? What was their biggest contribution to the project? What was
your biggest contribution?
6. How did this activity help you gain a better understanding of the size of our solar system?
Rubric
Calculations - conversions and calculations are all correct
______/ 10
Planet & “poster” - colorful, correctly sized, and informative
______/ 15
Post-lab questions - answered correctly in complete sentences
______/ 5
Participation - worked during class time and rated highly by partner
______/ 5
Total
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