Lunar and Planetary Institute

Space Stations - Beans in Space!
EXPLORE! Health in Space

Space Stations - Beans in Space!


Jumping BeansIn Beans in Space! children ages 8–13 perform 20 arm curls with cans that simulate the weight of beans on Earth, and the weight of the same number of beans on the Moon or in space. They explore what happens to muscles in space that do not have to fight the force of gravity.

What's the Point?

  • Weight and mass are not the same thing
  • Although mass remains the same in space, weight changes in microgravity
  • Because everything weighs less in space (including your own body parts!) your muscles do not need to work as hard as they did on Earth, and they begin to atrophy


The following materials are for one Beans in Space! activity set
Three sets are recommended for a station

  • 3 opaque non-breakable containers (coffee cans work well)
  • Tape (to seal the containers)
  • 3 cups of beans (for each Earth can only)
  • ½ cup of beans (for each Moon can)
  • Paper or foam to stuff inside the Earth and Moon cans so that the beans don't rattle
  • Labels for each can
  • Children's Guide

For the facilitator:


  • Prepare the three containers of Earth, Moon and and space beans. There is no reason to have exactly 1,559 beans in each of the Earth containers. Placing a specific number on the container label, however, will help the children to realize that even though the weight of an object may change in space, the mass of those objects will remain the same.
  • Label the can containing 3 cups of beans "1559 Beans on Earth", the cans containing 1/2 cup of beans, "1559 Beans on the Moon", and the empty can "1559 Beans in Space."
  • Make sure the lids on the containers are on tight or sealed so there can't be any peeking!
  • Place the sets of cans at the station with a copy of the Children's Guide


Described in the Children's Guide


Once they have completed the experiment, the children should understand that weight and mass are not the same thing, that weight is dependent upon the pull of gravity, and that in microgravity objects are weightless. Because objects, including body parts, essentially weigh nothing in space, our muscles do not have to work as hard and they, therefore, become weak and begin to atrophy. One of the foremost challenges for astronauts is to get enough exercise (2+ hours per day!) to offset this deterioration of muscles.

A Little Background for the Facilitator

Astronauts may seem to have a lot of fun in microgravity — doing flips in mid-air, pushing off effortlessly from one part of the spacecraft to sail to another part. However, there are some down sides for astronaut health!

On Earth, our muscles have to work when we walk and run and jump. Earth's gravity pulls against us, making our muscles work hard — and keeping them strong! On the Space Station objects have no weight — and little effort is required of our muscles to lift things or move around. Standing, walking, and even breathing on Earth requires more muscle strength than in space. Because we don't need as much muscle in space, our body stops maintaining them — our muscles atrophy. Astronauts have to exercise about 2 hours a day to force their muscles to work and stay healthy for their return to Earth. Even with the exercise, astronauts still experience some muscle loss and have to build their muscles when they are back home on Earth.

We'll face the same challenges on the Moon and Mars, though not so severely; the Moon's gravity is about 1/6th that of Earth's and Mars has about 1/3rd the gravity. So, our muscles will get a bit of a workout on the Moon and Mars, but we will still need to exercise more to ensure that we are healthy when we return to Earth.

"Mass" and "weight" often are interchanged, however, they are very different things. The mass of an object is simply how "much" there is of it — the amount of matter it contains, and that remains constant no matter where it is.1,559 beans are 1,559 beans — no matter where they are!

Weight, however, depends on gravity. Weight is mass multiplied by gravity. Because Earth's gravity is different from the Moon's gravity, an object of the same mass will weigh more on Earth than on the Moon. And it will not weigh anything in the microgravity environment of the Space Station (see notes on microgravity at the beginning of this module). So 1,559 beans on Earth weigh more than 1,559 beans in space.

Last updated
February 9, 2010

Back to top