Education and
Public Engagement
at the Lunar and Planetary Institute
Health in Space

Space Stations - Beans in Space!


Children perform 20 bicep curls with cans that model the weight of dried beans on Earth and the weight of the same number of beans on the Moon or in space. They explore how astronauts need to exercise each day — just like us on Earth — but for 2+ hours each day!

Activity Time

5 minutes

Intended Audience

Families or other mixed-age groups, including children as young as 4 years old with assistance from an older child, teen, or adult
School-aged children ages 5–7 and 8–9
Tweens up to about age 13

Type of Program

Facilitated hands-on experience
Station, presented in combination with related activities
Passive program
☐ Demonstration by facilitator

What's the Point?


For the facilitator:

For Each Group of 1–3 Children


There are approximately 3,000 beans in 3 cups of navy beans. Placing a specific number on the container label 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.

The day before the activity

Provide the “Earth,” “Moon,” and “Space” cans in a bag or bin, or place them at a table so that participants can access them.


1.  Share ideas and knowledge.

2.  Exercise like an astronaut! Encourage each participant to lift the can labeled “3000 Beans on the Moon” in one hand and the can labeled “3000 Beans on Earth” up and down 20 times. Invite them to do the same “workout” with the can labeled “3000 Beans in Space” compared with the “Earth” can in the other arm.

3.  Compare observations and connect them to the “real world.” Prompt the children to compare their experiences lifting each of the cans with other children and/or family members. Prompt them to connect that experience to what astronauts experience in space.

For older children, emphasize the concept that weight and mass are not the same things. Although mass remains the same in space, weight changes in microgravity. Ask them if they think a can filled with 3000 dried beans — or anything else — has the same mass on Earth as 3000 beans in space or on the Moon.

4.  Explain that in space (a microgravity environment), astronauts’ muscles become smaller and weaker (i.e., begin to atrophy). Their muscles don’t have to work hard to lift their bodies or the equipment that the astronauts use — it is like lifting the “Space” can. In space, where there is no gravity for their muscles to pull against, their muscles become weaker. On the Moon, which has about 1/6 the pull of gravity that Earth has, future explorers’ muscles will get a little bit of a workout.  

5.  Conclude. Summarize that astronauts work out almost two hours every day while they are in space and even then, they still lose muscle mass. Kids and adults on Earth also lose muscle mass if we don’t exercise enough! There are many challenges astronauts face as they live and work in space. Daily life in space is different than life on Earth, but in both environments humans have the same basic needs.