.Ask students for their definition of gravity. Access the Scientist Top Tips near the top of the page for Dr. Shara’s explanation of the concept. Explain that the force of gravity differs from planet to planet.

In Moon Olympics, students observe an animation of popular Earth activities like skate boarding. Then they make a prediction about how gravity would change that same activity if it were played on the moon. Students explore the results through animation and text.

Use this teacher solution to discuss predictions and results.
• Weightlifting Correct choice: 3 — On the Moon, you would be able to lift a barbell six times as big because gravity is one-sixth as strong as on Earth.
• Diving Correct choice: 3 — On the Moon, you wouldn’t even be able to dive because the Moon has no atmosphere or air pressure so the water would quickly evaporate.
• Golf Correct choice: 2 — On the Moon, you’d be able to hit a golf ball six times farther because gravity is one-sixth as strong as on Earth.
• Skateboarding Half Pipe Correct choice: 2 — On the Moon, you’d be able to jump higher, but you’d move more slowly since there would be less gravity to pull you back down.
• Parachuting Correct choice: 1 — On the Moon, your parachute wouldn’t even open because there’s no air! You’d free fall — slowly — to the Moon’s surface.

Ask students what results surprised them. Discuss what other popular Earth pastimes might be like on the moon.

Now that students have explored the effects of gravity and atmosphere on the Moon, they are ready to explore resources and form conclusions about how gravity, temperature, and atmosphere combine to make Earth a good home for humans – and how those factors differ on other planets.

Print and distribute copies of the Cause and Effect (PDF) graphic organizer. Have each student select a planet to focus on. Using the Investigate area and additional resources, have students fill in information about their planet. Finally, guide students to synthesize their facts and describe what life would be like on their selected planet.