Scale Model of the Solar System

Purpose

Build a scale model of the solar system large enough to feel the distances, and explain why textbook diagrams are misleading.

Setup

Scale the Sun to a 24 cm basketball. Every other distance follows:

$$d_{\text{model}}=d_{\text{real}}\times \frac{0.24\mathrm{m}}{1.39\times 10^9\mathrm{m}}$$

Calculate first

Body	Real distance from Sun (km)	Model distance	Model diameter
Mercury	$5.79\times 10^7$
Venus	$1.08\times 10^8$
Earth	$1.50\times 10^8$
Mars	$2.28\times 10^8$
Jupiter	$7.78\times 10^8$
Saturn	$1.43\times 10^9$
Uranus	$2.87\times 10^9$
Neptune	$4.50\times 10^9$

Then walk it

1. Place the basketball at one end of the field.
2. Walk each distance, leaving a marker with the planet’s name and its model diameter written on it.
3. Photograph the line from the Sun end.

Two questions to answer on the field

1. Can you see the Earth marker from the Sun? What is Earth’s model size?
2. At this scale, the nearest star is about 7 000 km away. Name a city that far from here.

Analysis

1. Why do textbook diagrams almost never use a consistent scale for both size and distance? What do they gain, and what do they cost?
2. Working at this scale, how large would the Moon be, and how far from Earth?
3. Voyager 1 is about $2.4\times 10^{10}\mathrm{km}$ away. Where does that put it in your model?

Hand in

• Completed calculation table, work shown
• Photograph of your model
• Analysis answers

Curriculum connection

E2.5

quantify distances in the solar system and the universe by applying an understanding of relative distances and sizes and using appropriate units of measure

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E2.4

describe major components of the solar system and the universe and compare their characteristics

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A1.3

apply an engineering design process and associated skills to design, build, and test devices, models, structures, and/or systems

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