Sun-Moon-Earth Automaton Lesson

A lesson for learning about gear ratios and the sun-moon-earth system. Explore engineering principles such as analysis, compound gears, and modeling.

Overall:

• Slideshow 
• Loctite (enough for all students)
• Hot glue
• Play dough (for decoration)
• Paper (so students can use spirographs)
• Pencils

Per student:

• 1x vex gear
• 2x 60 tooth gear
• 6x 10 tooth gear
• 4x 20 tooth gear
• 3x 30 tooth gear
• 3x 40 tooth gear
• 1x base
• 1x 60 tooth spirograph
• 1x 90 tooth spirograph
• 1x outer dowel
• 1x connector
• 5 3-inch dowels
• 1 7-inch dowel

This lesson is 2 hours long. If class time must be split, gear ratio review slides have been included.

Review the lesson plan beforehand. Refer to the corresponding slides for each part of the lesson.

Using a 3D printer, print the required number of parts for each student.

Lay out all materials on a table for easy access. Do not let students sit at this table. Students will come up to the table to get materials, or materials may be passed out by classroom personnel.

• Systems
• Ask: What are some examples of systems? What are systems? (2 min)
• Discuss: Share answers and explanations. (3 min)

• Spirographs
• Distribute: Spirographs and gears of each size to each student (2 min)
• Ask: What happens when you change the inner and outer gears of spirographs? What patterns do you notice? Highlight: Collaboration in groups (8 min)
• Discuss: Explore inner and outer gear ratios and share observations as a class. (3 min)
• Highlight: Rotational symmetry of spirograph patterns (2 min)

• Gear Ratios
• Ask: How many times does the blue gear spin for one revolution of the yellow gear? (2 min)
• Discuss: Introduce the concept of ratios and share answers. (3 min)

• Explanation: Briefly explain the roles of gears in a gear train. (2 min)

• Simplifying Systems
• Ask: How can we simplify the sun-moon-earth system to create a model? (2 min)
• Discuss: Share ideas and approaches. (1 min)

• Introduction: Explain compound gears and their significance in gear systems. (5 min)

• Gear Problem
• Ask: How many times does the blue gear spin for one revolution of the yellow gear? (2 min)
• Discuss: Encourage students to solve the problem using their understanding of ratios. (3 min)

• Demonstration: Assemble a sample sun-moon-earth system while explaining how you put the base together. (5 min)

• Allow students the remainder of the class time to explore the model further and offer assistance as necessary.

If the activity is split between classes, use the gear ratio review slides for reinforcement.