## Activity for Parents and Teachers to Teach the Size and Distances of Planets

By Raphael Kohlberg

Practically all kids are interested in the planets and outer space. You can encourage their interests in astronomy while teaching them math and science at the same time with these simple activities for older elementary students. These activities will also help reinforce critical thinking skills.

Before beginning, make sure your child has some basic background information such as the names and order of the planets in our solar system. Showing your child a model or illustration would be helpful. Explain to your child that most illustrations show the planets in relative size. Discuss with your child the meaning of relative size, showing that the pictures depict how big the planets are when compared to each other and the sun. Ask your child to identify the smallest planet and the largest planet.

If your child understands the sizes and ratios of planets fairly easily, challenge them a little bit more by explaining the astronomical unit (AU). (An AU is a simplified number used to describe a planet’s distance from the sun. An AU is equal to the average distance from Earth to the sun, approximately 149,600,000 kilometers.) Help your child draw the following conclusions:

• Planets farther away from the sun than Earth have an AU greater than 1.
• Planets closer to the sun than Earth have an AU less than 1.

Teachers can emphasize the distance of the planets from the sun by taking a class outside to a large area. Different students could each represent a planet by taking the following number of steps away from an object representing the sun:

• Mercury = 1 step from the sun
• Venus = 2 steps from the sun
• Earth = 2.5 steps from the sun
• Mars = 4 steps from the sun
• Jupiter = 13 steps from the sun
• Saturn = 24 steps from the sun
• Uranus = 49 steps from the sun
• Neptune = 76 steps from the sun

After portraying the model, the teacher should ask students to describe what they observed about the distances of the planets from the sun and from each other. The teacher should point out the math connection of this activity, and thus explain how closely related math, science, and outer space actually are.