Quantitative Skills > Teaching Resources > Activities > BotEC: Volume of the Earth and Sun

Back-of-the-Envelope Calculations: Volume of the Earth and Sun

Barbara Tewksbury

Hamilton College
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Suppose you and your friends wanted to make a scale model of the Earth and the Sun. You start by cutting a one-inch cube of Play-Doh to represent the volume of the Earth.

- How many one-inch Play-Doh cubes would you have to cut in order to represent the volume of the Sun at the same scale?

- If you stacked the blocks up into a cube, how big would the cube be?

- And, finally, if you and all your friends mashed and shaped that huge cube into a sphere, and you made a sphere out of the Earth cube as well, how far away from your Play-Doh Sun would you have to hold your scale Earth to match the true scale of the solar system?

References and Resources

This SERC page describes the use of Back of the Envelope Calculations

A View from the Back of the Envelope (more info) : This site has a good number of easy simulations and visualizations of back of the envelope calculations.

The Back of the Envelope ( This site may be offline. ) : This page outlines one of the essays in the book "Programming Pearls" (ISBN 0-201-65788-0). The book is written for computer science faculty and students, but this portion speaks very well to back of the envelope calculations in general.

Controlled Vocabulary Terms

Subject: Geoscience:Lunar and Planetary Science
Resource Type: Activities:Classroom Activity:Short Activity
Special Interest: Quantitative
Quantitative Skills: Estimation
Ready for Use: Ready to Use
Topics: Solar system

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