Type of Lesson
Hands-on Activity

Time Needed
45 - 50 minutes

Objectives / Standards Addressed

• Describe the sun, moon, and earth
• Describe, compare, and explain the motions of planets, moons, and comets in the solar system
  
  Summary of Lesson
  This is an introductory lesson about the planets of our solar system.
  
  Material for each group of 4 students
  50 grams of gray clay 100 grams of yellow clay 50 grams of green clay 50 grams of blue clay 50 grams of red clay a balance for each group
  
  Procedure
  1. Ask the question, "What do we know about the planets?" Get students to brainstorm about this question.
  
  2. Explain to the students that you can study astronomy through the use of models. The students will be creating a model of the solar system using clay to represent different planets and other objects in the solar system (asteroids, moons, etc.). The students can use as much or as little of the clay their group is provided. Students may use their books or previous knowledge to try to make an accurate model for the solar system. Tell students that their models should represent the true size and scale of the solar system.
  
  3. Allow 15-20 minutes for the students to build their models. During this time students should also pick a spokesperson to explain the model to the rest of the class.
  
  4. Lead a class discussion about the models:
  
• What are the strengths of our models?
  
• What are the weaknesses of our models?
  
• How are our models different from the real solar system?
  
• How are our models similar to the real solar system?
  
  5. As a conclusion, explain to the students that 99% of the mass of the solar system is found in the sun. That leaves only 1% for the rest of the solar system. In other words, for the models to be an accurate representation in terms of mass, 99 grams of clay would be needed to represent the sun, and only 1 gram could be used for all of the planets, 59 moons, and thousands of asteroids. Hold up 99 grams of yellow clay for the sun, and 1 gram of clay that represents everything else in the solar system. It is hard to believe, isn't it?
  
  Notes to the Teacher
  If there is time in the instruction period, ask students how they would change their models to make them more accurate.