published by
the National Aeronautics and Space Administration

This learning module for Grades 5-8 contains four lessons that explore the scale, relative sizes, and composition of the planets in our solar system. Each lesson provides opportunity for students to build physical models and investigate within a context that is easily understood. Lesson 1 models the orbital distances between the planets; Lesson 2 compares the relative sizes of the planets to those of fruits and vegetables; Lesson 3 models planetary interiors/cores; and Lesson 4 examines characteristics of planet surfaces that make them able to support or not support life.

This resource is part of NASA's Solar System Exploration website.

See Related Materials for an editor-recommended digital solar system simulator and for a link to NASA's Kepler Mission, "A Search for Habitable Planets".

3-5: 4A/E4. The earth is one of several planets that orbit the sun, and the moon orbits around the earth.

6-8: 4A/M3. Nine planets of very different size, composition, and surface features move around the sun in nearly circular orbits. Some planets have a variety of moons and even flat rings of rock and ice particles orbiting around them. Some of these planets and moons show evidence of geologic activity. The earth is orbited by one moon, many artificial satellites, and debris.

4B. The Earth

6-8: 4B/M2ab. The earth is mostly rock. Three-fourths of the earth's surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin layer of air.

6-8: 4B/M2cd. Earth is the only body in the solar system that appears able to support life. The other planets have compositions and conditions very different from the earth's.

4F. Motion

6-8: 4F/M3b. If a force acts towards a single center, the object's path may curve into an orbit around the center.

4G. Forces of Nature

6-8: 4G/M2. The sun's gravitational pull holds the earth and other planets in their orbits, just as the planets' gravitational pull keeps their moons in orbit around them.

11. Common Themes

11B. Models

3-5: 11B/E4. Models are very useful for communicating ideas about objects, events, and processes. When using a model to communicate about something, it is important to keep in mind how it is different from the thing being modeled.

6-8: 11B/M1. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly. They are also used for processes that are too vast, too complex, or too dangerous to study.

11D. Scale

6-8: 11D/M3. Natural phenomena often involve sizes, durations, and speeds that are extremely small or extremely large. These phenomena may be difficult to appreciate because they involve magnitudes far outside human experience.

12. Habits of Mind

12B. Computation and Estimation

3-5: 12B/E3. Judge whether measurements and computations of quantities such as length, weight, or time are reasonable by comparing them to familiar values.

6-8: 12B/M5. Estimate distances and travel times from maps and the actual size of objects from scale drawings.

Common Core State Standards for Mathematics Alignments

Standards for Mathematical Practice (K-12)

MP.4 Model with mathematics.

Ratios and Proportional Relationships (6-7)

Understand ratio concepts and use ratio reasoning to solve
problems. (6)

6.RP.3.a Make tables of equivalent ratios relating quantities with whole number measurements, find missing values in the tables, and plot the pairs of values on the coordinate plane. Use tables to compare ratios.

6.RP.3.d Use ratio reasoning to convert measurement units; manipulate and transform units appropriately when multiplying or dividing quantities.

Expressions and Equations (6-8)

Reason about and solve one-variable equations and inequalities. (6)

6.EE.7 Solve real-world and mathematical problems by writing and solving equations of the form x + p = q and px = q for cases in which p, q and x are all nonnegative rational numbers.

Solve real-life and mathematical problems using numerical and
algebraic expressions and equations. (7)

7.EE.4.a Solve word problems leading to equations of the form px + q = r and p(x + q) = r, where p, q, and r are specific rational numbers. Solve equations of these forms fluently. Compare an algebraic solution to an arithmetic solution, identifying the sequence of the operations used in each approach.

<a href="http://www.compadre.org/portal/items/detail.cfm?ID=12446">National Aeronautics and Space Administration. NASA Johnson Space Center: Modeling the Solar System. Washington: National Aeronautics and Space Administration, 2003.</a>

NASA Johnson Space Center: Modeling the Solar System, (National Aeronautics and Space Administration, Washington, 2003), <http://solarsystem.nasa.gov/educ/lesson-view.cfm?LS_ID=722>.

NASA Johnson Space Center: Modeling the Solar System. (2003). Retrieved December 18, 2014, from National Aeronautics and Space Administration: http://solarsystem.nasa.gov/educ/lesson-view.cfm?LS_ID=722

National Aeronautics and Space Administration. NASA Johnson Space Center: Modeling the Solar System. Washington: National Aeronautics and Space Administration, 2003. http://solarsystem.nasa.gov/educ/lesson-view.cfm?LS_ID=722 (accessed 18 December 2014).

NASA Johnson Space Center: Modeling the Solar System. Washington: National Aeronautics and Space Administration, 2003. 18 Dec. 2014 <http://solarsystem.nasa.gov/educ/lesson-view.cfm?LS_ID=722>.

@misc{
Title = {NASA Johnson Space Center: Modeling the Solar System},
Publisher = {National Aeronautics and Space Administration},
Volume = {2014},
Number = {18 December 2014},
Year = {2003}
}

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An interactive orbital simulator: build a system of heavenly bodies and watch the gravitational motions. Users can set initial positions, velocities, and masses of up to 4 planets.

A link to NASA's Kepler Mission website, whose goal is to survey the Milky Way Galaxy to discover planets where liquid water and, thus, life might exist. Includes an array of resources for the K-12 classroom.