Name ______Class Period _____

Proportional Reasoning Task: Journey through the Solar System

1. If a rock weighs 1 lb on the Earth, estimate how much the rock would weigh on the moon. Show the method you used.

2. Define “unit rate”:

3. If a rock weighs 1 lb on the moon, estimate how much the rock would weigh on the Earth. Show the method you used.

4. Your little dog, Toto, weighs 5.4 lbs. on the Earth. Estimate Toto’s weight on the moon. Show your method.

5. Your spacesuit weighs 38 lbs on the moon. How much does it weigh on Earth? Show your method.

6. Now that you have visited the moon, you would like to check out a few planets. Find the unit rates and then calculate weights for the following planets:

If weight on Earth is 120 lbs
The weight on other planets = / Unit Rate Conversion Factor: 1 lb on Earth = ???? lbs on the other planet
Earth’s moon / 19.9 lbs
Mercury / 45.3 lbs
Venus / 108.8 lbs
Earth / 120 lbs
Mars / 45.2 lb
Jupiter / 283.6 lbs
Saturn / 127.6 lbs
Uranus / 106.6 lbs
Neptune / 135 lbs
Sun
(not a planet!) / 3248.6 lbs

7. Finding a pattern: describe the method you used to fill in the table, and then create a generalized equation for calculating a unit rate conversion factor.

8. Use generalized equation you developed to find the unit rate for converting weight on Jupiter’s moon Callisto. (120 lbs on Earth is 15.16 lbs on Callisto)

9. If your car weighed 100 lbs on Callisto, how much would it weigh on Earth?


Name ______Class Period _____

Proportional Reasoning Homework:

Journey through the Solar System

Note: unit rates calculated on the task sheet

Proportional Reasoning Task: Journey Through the Solar System

1. Cell phones weight about ¼ lb. Would you be strong enough to lift a cell phone on the sun? (Assuming you and the phone weren’t crushed or burned.) Find the weight of the cell phone on the sun and explain.

2. A refrigerator weighs about 300 lbs on Earth. Could you lift a refrigerator if you were on the moon? Find the weight of the refrigerator on the moon and explain.

3. You can use the same unit rates for gravity to find out how high a person can jump. Suppose you can jump a 4 foot tall fence on the Earth.

How tall a fence could you jump on the moon? ______

How high a fence could you jump on Mars? ______

How high a fence could you jump on Jupiter? ______


Teacher Resource for

Proportional Reasoning: Journey through the Solar System

Core Standards: 7.RP.1, 2b-c

Teacher Resources

An online weight calculator for the sun, other planets and various moons: http://www.exploratorium.edu/ronh/weight/