Moon Leap

Opening Discussion

Ask your students if they have ever heard of gravity before. Does anyone know how gravity affects us on Earth? Look for responses like “It’s what pulls you back down to Earth when you jump up.” Or “It’s what keeps us on the ground.”

Ask if anyone knows if the effect of gravity on the Moon is the same, stronger, or weaker than it is on Earth. After a few guesses, if you can, show them this NASA video of an astronaut jumping on the Moon (click here) and then have them guess again. After a few guesses (or, if you couldn’t show the video), tell them that the Moon’s gravity is weaker than the Earth’s – in fact it is 1/6^th as strong as on Earth. When you’re on the Moon, you are 1/6^th as heavy, but your muscles are as strong as they are on Earth, so you can jump 6 times farther.

The Challenge

See how high you can jump, and then calculate how high that jump would be on the Moon!

Doing the Activity

There are two versions of this activity, high jump and long jump. If you have time, try both!

High Jump Version:

1. Each child who wishes to try should get a turn to jump. For students who have difficulty jumping, you can challenge them to throw a ball or beanbag as far as they can, and measure that distance instead.
2. Give these instructions to each child:
   • Stand facing the chart paper on the wall, holding a marker.
   • Reach your hand over your head, as high as you can, and make a mark on the paper with the marker. This is your starting point.
   • Take a small step back (no running starts!), bend your knees and jump as high as you can, making a mark on the paper with your marker at the highest point.
   • Measure the distance between your starting mark and your jumping mark. This is how high you jumped. Write down your measurement.
3. After every child who wants to try has had a turn to jump, have your students calculate how high their jump would have been on the Moon by multiplying their measurement by 6. For older children, encourage them to do the math on paper. For younger children who have not yet learned how to multiply, you can use a calculator. The resulting Moon jump measurement is how high their feet would be off the ground if they had jumped on the Moon. You can have each child record this height on the paper on the wall, measuring this time from the floor to their Moon jump measurement.

Long Jump Version:

1. Each child who wishes to try should get a turn to jump. For students who have difficulty jumping, you can challenge them to throw a ball or beanbag as far as they can, and measure that distance instead; or challenge a child in a wheelchair to see how far they can propel their chair with one big push.
2. Children should work in teams of 2-4 for this activity. If your resources or space are limited, this activity can also be accomplished instead as one large group, with each child taking a turn jumping, and you marking their jumps on the floor. Give these instructions to each team:
   • Make a mark on the floor with a piece of tape. This is your starting line. Jumpers should stand with their toes touching this mark.
   • When you are ready, and without taking a running start, bend your knees and jump as far forward as you can from a standing position. One member of the team should be in charge of noting where your toes landed. Another member of the team can place a piece of tape there and write your name on that piece of tape.
   • Measure the distance from the starting line to your jump, and record that number somewhere.
3. After every child who wants to try has had a turn to jump, have your students calculate how far their jump would have been on the Moon by multiplying their measurement by 6. For older children, encourage them to do the math on paper. For younger children who have not yet learned how to multiply, you can use a calculator. You can have each child record their distance in some central location so you can see the whole group’s results.

Let’s Talk About It

Ask your students if they were surprised by the results. Could anyone jump over their own head on the Moon, or farther than their own height? Who jumped the highest/farthest? What do they think it would be like to walk on the Moon? What would it be like to play basketball, soccer, or another sport? Reinforce the idea that the reason they can jump higher or farther on the Moon is because gravity is weaker there; and the reason that they can jump less high or far on Earth is because gravity is stronger.

Build On What They Talked About

If your students would like to, they can try again. You can also try the standing long jump, if you already did the high jump, and the high jump if you already did the long jump.

Another extension is to try the same activity for different bodies in our solar system. The activity is the same, but the calculations are different. Instead of multiplying by 6, use these numbers for other planets, moons, and the Sun:

• Mercury – 2.6
• Venus – 1.1
• Mars – 2.7
• Jupiter – 0.4
• Saturn – 0.94
• Uranus – 1.1
• Neptune – 0.9
• Pluto – 15
• Sun – 0.035
• Titan – 7.1 (Moon of Saturn)
• Ganymede – 6.7 (Moon of Jupiter)
• Triton – 12.8 (Moon of Neptune)
• Ceres – 33.3 (Dwarf planet in the Asteroid Belt)

Visit NASA’s solar system site at http://solarsystem.nasa.gov/planets for amazing images and information on each of these planets and moons, which you can share with your students.