Play Dough Planets (Grades 3-5)

How big is Mars? What about Jupiter? Find out for yourself with this big-time activity.

The planets in our solar system are so huge and so far apart that it can be hard to imagine how they compare. Find out for yourself by crafting some planets of your own. But get ready, because to build planets, you’re going to need a LOT of raw materials!

What You Need

• 3 pounds of modeling clay or play dough (make your own play dough using this recipe)

What To Do

Before you start building, make a prediction. Which planet do you think is the biggest? The smallest? Which two planets do you think are closest in size? How much bigger is the Earth than its moon? Write down your predictions and set them aside.

Earth vs. Moon

1. Divide the dough into 50 equal-sized balls (as equal as possible).
2. Choose an average-sized ball and set it aside.
3. Squash the other 49 balls back together. You now have the Earth and Moon.

Squash your dough back together before moving on to the next experiment.

Earth, Moon and Mars

1. Divide your dough in half. One half is Earth.
2. Make seven balls out of the other half. One ball is Mars.
3. Take another one of these seven balls, and divide it into seven. One of those is the moon.

To do a scale model with these, Earth and Mars would be seven city blocks apart! Squash your dough back together before moving on to the next experiment.

Solar System

1. Write the name of each of the nine planets on separate pieces of paper. Spread the labeled papers out on a table. This is where you will be placing the play dough to make each of the planets.
2. Divide the dough into 10 equal balls. Squash 6 of them together. This will be Jupiter. Place the ball on the paper labeled Jupiter.
3. Take another 3 balls and squash them together. This is part of Saturn — place this ball on the paper labeled Saturn.
4. Divide the ball of play dough that is left into 10 equal parts. Squash 5 of them together and add them to Saturn. Take 2 and squash them together. This is Neptune. Place the Neptune ball on its paper. Take another 2 and squash them together. This is Uranus. Place the Uranus ball on its paper.
5. With the ball that is left, make 10 equal sized balls. Squash 9 of them together, and add to Saturn. Saturn is complete.
6. Divide the remaining ball into 2. One part is Earth. Place this ball on its paper.
7. Now this is when things get tricky! Divide the ball that is left into 10. Nine of them make up Venus. Place that ball on the paper labeled Venus.
8. Make 10 balls out of the one that is left. Use 9 to create Mars. Place the Mars ball on its paper.
9. Divide the ball of play dough that is left into 10. Nine of them make up Mercury. Place the Mercury ball on the paper labeled Mercury.
10. The last ball is Pluto.

What About the Sun?

The sun is so much larger than all of the planets that if you used a 3-pound tub of play dough to make the nine planets, it would take 980 tubs to make the sun!