What If? Lab
What if you jumped on the Moon?
On the Moon, the pull that brings you back down is much weaker. How high could you jump? Jump on the Moon with Olly!
The Moon's gravity is only about one sixth as strong as Earth's. In our model, a jump that lifts a child about 29 centimeters on Earth carries them about 1.8 meters on the Moon, and they stay in the air for about 3 seconds instead of half a second.
For a fixed take-off speed v, jump height h = v²/2g and air time t = 2v/g both scale as 1/g. With the model's 2.4 m/s take-off and lunar g = 1.62 m/s², the jump rises from 0.29 m to 1.78 m and lasts 2.96 s instead of 0.49 s: about 6.06 times as high and as long.
The big question
When you jump, you go up a little. Then you come back down. Earth pulls you down.
The Moon pulls too, but much less. What would happen if you jumped on the Moon?
Every jump is a contest between your legs and gravity. Your legs push you up off the ground, and gravity pulls you back down, slowing you until you stop rising and fall.
The Moon is much smaller than Earth, and its pull is much weaker. So if you jumped just as hard on the Moon, how high would you go, and how long would you hang in the air? In this lab you can jump on Earth and on the Moon and compare.
A jumper leaves the ground with some upward speed and then decelerates at the local gravitational acceleration g until reaching the top of the jump. Change g and both the height and the time aloft change.
This lab compares the same jump on Earth (g = 9.81 m/s²) and on the Moon (1.62 m/s²) with a simple ballistic model, and asks what the model leaves out about real jumping in a spacesuit.
Try the experiment
Make a prediction
On Earth your jump goes up a little. You jump just as hard on the Moon. How high do you go?
A jump lifts a child about 29 centimeters on Earth. With the same push on the Moon, about how high would the model's jump go?
A 2.4 m/s take-off reaches 0.29 m on Earth. Under lunar gravity, the model's jump height is about…
- About the same, 29 centimeters
- About 1.8 meters, six times higher
- About 29 meters, a hundred times higher
| Control | In our world | What if… | Range |
|---|---|---|---|
| Where you jump · The world you are standing on. Each world pulls with its own strength; the Moon pulls about one sixth as hard as Earth. | 2 | 3 | 0–9 |
| Your mass · How much of you there is. It stays the same on the Moon; only your weight changes. | 30 kg | — | 10–120 kg |
| Jump speed · How fast your legs push you up as you leave the ground. The model keeps it the same on every world. | 2.4 m/s | — | 0.5–4 m/s |
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Established fact
The Moon pulls you down much less than Earth.
Gravity on the Moon's surface is about one sixth of Earth's (NASA).
Lunar surface gravity is 1.62 m/s² against Earth's 9.80, a ratio of about 0.165 (NASA Moon Fact Sheet).
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What the model shows
In the model, your jump goes about six times higher on the Moon.
In this model, a jump of about 29 centimeters on Earth reaches about 1.8 meters on the Moon, and lasts about 3 seconds instead of half a second.
Model, v = 2.4 m/s: h = 0.294 → 1.778 m and t = 0.489 → 2.963 s, both × 6.06 (= 9.81/1.62).
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What the model shows
In the model, a scale on the Moon shows a much smaller number.
In this model, a child who weighs 30 kilograms on an Earth scale would see about 5 kilograms on the Moon, though their mass is still 30.
Model: W = 30 kg × 1.62 m/s² = 48.6 N, displayed as 4.95 kg on an Earth-calibrated scale.
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Established fact
Astronauts on the Moon seemed to bounce as they walked.
NASA says the Moon's low gravity is why astronauts in moonwalk films seem to almost bounce across the surface.
NASA links the bounding gait seen in moonwalk footage to the one-sixth lunar gravity.
In our world
On Earth, a child's jump goes up about as high as a ruler is long.
It is over very fast. Up and down takes about half a second.
In the model, a child pushes off the ground at 2.4 meters per second. On Earth, gravity takes away about 9.8 meters per second of that upward speed every second, so the child rises about 29 centimeters, nearly the length of a 30-centimeter school ruler, and lands about half a second after leaving the ground.
The model's child has a mass of 30 kilograms, and an Earth bathroom scale shows 30.
With v = 2.4 m/s and g = 9.81 m/s², the model gives h = v²/2g = 0.294 m and t = 2v/g = 0.489 s. A 30 kg child weighs W = mg = 294 N, which an Earth-calibrated scale displays as 30.0 kg.
The model treats the jumper as a point leaving the ground at a fixed speed, with no air resistance; it ignores how a real jump uses crouching, arm swing and the ground's firmness.
Jump on the Moon
In our pretend lab, Olly takes you to the Moon. You jump just as hard as before.
Up, up, up you go, six times higher than on Earth! Then you float down slowly. It takes about 3 seconds.
Choose 'Moon' and jump again with exactly the same push. The Moon's gravity takes away only about 1.6 meters per second of upward speed each second, so you keep rising for much longer. The model's jump reaches about 1.8 meters, about six times as high as on Earth.
Coming down is slow too. The whole jump lasts about 3 seconds instead of half a second. And the bathroom scale? It shows only about 5 kilograms, though you are made of exactly the same amount of you.
With g = 1.62 m/s², the model gives h = 1.778 m and t = 2.963 s, both 6.06 times the Earth values, since 9.81/1.62 = 6.06. Weight falls to 48.6 N, 16.5 percent of Earth's, which an Earth-calibrated scale reads as 4.95 kg; mass stays 30 kg.
The ratio is independent of take-off speed in the model: any jump is 6.06 times higher and longer on the Moon. Because time aloft scales as 1/g and not 1/√g, the motion looks strikingly slow.
Why it happens
The Moon is much smaller than Earth. So it pulls on you much less.
A small pull slows you down only a little. So you keep going up for a long time.
How hard a world pulls depends on how much stuff it is made of and how big it is. The Moon has only about one eightieth of Earth's mass, and its radius is about a quarter of Earth's. Put together, its pull at the surface is about one sixth of Earth's.
A weaker pull slows your rise more gently, so the same push carries you higher, and it speeds up your fall more gently, so you drift down slowly. Your legs are just as strong; the Moon just does not fight back as hard.
Surface gravity is g = GM/R². NASA's fact sheet gives the Moon a mass of 0.07346 × 10²⁴ kg (1.23 percent of Earth's) and a mean radius of 1,737.4 km (0.273 of Earth's), so g_Moon/g_Earth ≈ 0.0123 ÷ 0.273² ≈ 0.165, matching its listed 1.62 m/s².
With fixed take-off speed, energy conservation gives h = v²/2g and kinematics t = 2v/g. The model's limits: it fixes take-off speed, assumes uniform gravity and no air, and does not model a spacesuit, footing or how hard a person can really push off on loose, dusty ground.
Real moonwalkers
Real astronauts have walked on the Moon. In videos, they seem to bounce along!
That is because the Moon's pull is so weak.
Astronauts have really walked on the Moon. NASA says that the Moon's gravity, one sixth of Earth's, is why astronauts in films of moonwalks seem to almost bounce across the surface. They left behind equipment, flags and even a camera.
The ground they bounced on is covered in gray, powdery dust and rocks, called regolith, made by billions of years of space rocks hitting the surface. Real astronauts wore spacesuits, which our model leaves out, so a real moon jump would not match the model exactly.
NASA attributes the bouncing gait seen in moonwalk footage to lunar gravity of one sixth of Earth's. The surface is a rubble layer of charcoal-gray dust and debris, the regolith, ground up by impacts over billions of years, above fractured bedrock.
The model's fixed take-off speed is a simplification: real lunar movement depended on suits, footing on regolith and technique, so actual jump heights would not scale exactly as 1/g. What it isolates cleanly is the role of g.
Amazing facts
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Astronauts left a camera on the Moon.
If you visited the right places on the Moon, you would find equipment, American flags and even a camera left behind by astronauts.
NASA notes that equipment, American flags and a camera left by astronauts remain on the lunar surface.
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One crater on the Moon is wider than a big city.
Tycho Crater on the Moon is more than 85 kilometers wide.
With almost no atmosphere to slow impactors, the Moon is heavily cratered; Tycho is more than 85 km across (NASA).
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There is ice hiding in dark places on the Moon.
Spacecraft have found ice in places near the Moon's poles that are always in shadow.
Missions including Lunar Prospector, LCROSS and LRO found high concentrations of water ice in permanently shadowed polar regions (NASA).
Words to know
- gravity
- the pull between objects that makes things fall toward a planet or moon
- mass
- how much stuff something is made of; it is the same everywhere
- weight
- how hard gravity pulls on your mass; it changes from world to world
- regolith
- the layer of dust and broken rock covering the Moon
- take-off speed
- how fast you are moving upward as your feet leave the ground
Discovery challenge
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How strong is the Moon's pull compared with Earth's?
About how strong is gravity on the Moon compared with Earth?
Lunar surface gravity is about what fraction of Earth's?
- About one sixth as strong
- Twice as strong
- Exactly the same
Show the answer
About one sixth as strong
About one sixth: much weaker.
About one sixth, so you feel much lighter.
About 0.165 (1.62 vs 9.80 m/s²).
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In the model, how high does your Moon jump go?
In the model, a 29-centimeter Earth jump goes about how high on the Moon?
The model's lunar jump height for a 2.4 m/s take-off is about…
- About 1.8 meters
- About 29 centimeters
- About 29 meters
Show the answer
About 1.8 meters
About 1.8 meters, six times as high as on Earth!
About 1.8 meters, six times as high.
…1.78 m (v²/2g with g = 1.62).
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On the Moon, which stays the same: your mass or your weight?
When you go to the Moon, what stays the same?
Moving from Earth to the Moon leaves which quantity unchanged?
- Your mass
- Your weight
- How long a jump lasts
Show the answer
Your mass
Your mass! There is the same amount of you.
Your mass stays the same; your weight is about one sixth.
Mass; weight W = mg changes with g.
Experiments to try
- Watch Try it What If? Lab What if you lived on Mars? You would be made of exactly the same amount of stuff on Mars, but Mars pulls on you less than Earth does. In our model, a bathroom scale there would show only a little over a third of your Earth reading, and your jumps would go more than twice as high.
- Watch Try it What If? Lab What if you could stand on Saturn? You could not really stand on Saturn: it is a ball of gas and liquid with no solid surface. But imagine floating at its cloud tops. Saturn has 95 times Earth's mass, yet in our model you would weigh only about 14 percent more than at home, because Saturn is so wide that its cloud tops are very far from its center.
- Watch Try it What If? Lab What if gravity disappeared? Gravity is the pull that makes a dropped ball fall and keeps your feet on the ground. Switch it off in our model and watch what a ball does instead, then find out why astronauts float.
- Watch Try it What If? Lab What if you tried to swing in space? A swing is a pendulum: gravity pulls the seat back down to the middle every time it rises. In our model, a swing with 2-meter ropes takes about 2.9 seconds to go there and back on Earth. Switch gravity off and the seat simply stays where you let it go.
- Watch Try it What If? Lab What if you tossed a ball straight up? A ball tossed straight up slows down, stops for a split second at the top, then falls back. In this lab you toss it at 8 meters per second and watch its speed. Here is the surprise: it comes back past your starting point just as fast as it left.
- Watch Try it What If? Lab What if a pendulum clock went to the Moon? A pendulum clock keeps time by counting swings, and gravity sets how fast each swing goes. In our model, a 1-meter pendulum takes about 2 seconds per swing on Earth but almost 5 seconds on the Moon, so a clock set up on Earth would show only about 24 minutes for every real hour.
Explore next
- Watch Try it What If? Lab What if you lived on Mars? You would be made of exactly the same amount of stuff on Mars, but Mars pulls on you less than Earth does. In our model, a bathroom scale there would show only a little over a third of your Earth reading, and your jumps would go more than twice as high.
- Watch Try it What If? Lab What if you could stand on Saturn? You could not really stand on Saturn: it is a ball of gas and liquid with no solid surface. But imagine floating at its cloud tops. Saturn has 95 times Earth's mass, yet in our model you would weigh only about 14 percent more than at home, because Saturn is so wide that its cloud tops are very far from its center.
- Watch Try it What If? Lab What if gravity disappeared? Gravity is the pull that makes a dropped ball fall and keeps your feet on the ground. Switch it off in our model and watch what a ball does instead, then find out why astronauts float.
- Watch Try it What If? Lab What if you tried to swing in space? A swing is a pendulum: gravity pulls the seat back down to the middle every time it rises. In our model, a swing with 2-meter ropes takes about 2.9 seconds to go there and back on Earth. Switch gravity off and the seat simply stays where you let it go.
- Watch Try it What If? Lab What if you tossed a ball straight up? A ball tossed straight up slows down, stops for a split second at the top, then falls back. In this lab you toss it at 8 meters per second and watch its speed. Here is the surprise: it comes back past your starting point just as fast as it left.
- Watch Try it What If? Lab What if a pendulum clock went to the Moon? A pendulum clock keeps time by counting swings, and gravity sets how fast each swing goes. In our model, a 1-meter pendulum takes about 2 seconds per swing on Earth but almost 5 seconds on the Moon, so a clock set up on Earth would show only about 24 minutes for every real hour.
- Watch What If? Lab What if the Moon had air? The Moon has almost no air, so its sky is always black and it has no weather. Scientists have found that the Moon once had an atmosphere, billions of years ago, but it was lost to space or became part of the ground. Explore what air would change, and why small worlds lose theirs.
- Watch Try it What If? Lab What if Earth had no Moon? The Moon's pull stretches Earth's oceans and gives us most of our tides. Take the Moon away in our tide model and see what is left: the Sun still makes tides, but they are less than half as big as the Moon's.
For parents & teachers
What children will learn
- The Moon's gravity is about one sixth of Earth's.
- With the same push, a jump on the Moon goes about six times as high and lasts six times as long.
- Mass stays the same everywhere; weight depends on gravity.
- Models simplify: real moon jumps also depend on spacesuits and footing.
Recommended ages: 4 to 17 · About 10 minutes
Talk about it
- What games would be fun, or tricky, in one-sixth gravity?
- Why is your mass the same on the Moon but your weight different?
- What might make a real jump on the Moon harder than the model says?
Try at home or in class
- Measure how high you can jump against a wall with a grown-up's help, then multiply by six to find your model Moon jump.
- Count how long a jump lasts by filming it on a phone, then multiply by six for the Moon.
Key vocabulary: gravity, mass, weight, regolith, take-off speed
Where these facts come from
- Earth's Moon: Facts , NASA Science
- Moon Fact Sheet , NASA Goddard Space Flight Center
- Earth Fact Sheet , NASA Goddard Space Flight Center
- University Physics Volume 1, §5.4 Mass and Weight , OpenStax
Checked, not yet human-reviewed. Last updated October 24, 2026. Spotted a mistake? Tell us.