Education and
Public Engagement
at the Lunar and Planetary Institute
Explore! Jupiter's Family Secrets

Investigating the Insides


Investigating the Insides is a 30–minute activity in which teams of children, ages 10 to13, investigate the composition of unseen materials using a variety of tools. This open-ended engagement activity mimics how scientists discover clues about the interiors of planets with cameras and other instruments onboard spacecraft.

What's the Point?


For each group of 20 to 30 children:

For each child:

For the facilitator:



1. Ask the children how scientists study planets.

Facilitator's Note: This activity serves as an open-ended engagement activity on how we study the planets. Scientists are able to directly observe some of a planet's characteristics, such as location in the solar system, size, mass, density, gravity, external composition, and more. Mathematicians were able to calculate the planets' orbits based on observations of their movements across the night sky. Telescopes and tools that measure invisible wavelengths of light, called spectrometers, allowed scientists a closer look at the planets' external compositions.

Scientists study the interiors through models they create, which are based on a planet's observable characteristics. Earth's interior is studied in part through seismic data. The giant planets and Earth all have magnetic fields, which are detectable by the radio signals they emit. Magnetic fields are generated deep within planets, so they provide clues to the internal structure and composition. Orbiting spacecraft experience slight variations in their trajectories that help scientists understand a planet's gravity well. By measuring the gravitational pull, scientists can tell more about how a planet's heavy material is distributed in its interior. That information will help them make educated inferences about a planet's composition.

2. Share that the Juno mission launched in 2011 to study Jupiter.

3. Tell the children that they are going to explore how we study planets, using balloons as models.

4. Invite the children to divide into groups of four and use their senses and the tools in the room to investigate their balloons. Each child or group should write down their observations in their journals. They must be careful not to pop the balloons, but they are allowed to use their senses and other tools to study their "planets." Have each team record a hypothesis about what is inside their balloon in their journals.

5. One at a time, invite each group to share their observations with the others. Ask the groups to share their hypothesis on what is inside of their balloons.


Ask the children to compare their balloons to planets.

Reiterate that Juno will investigate Jupiter — like the children did with their balloons — using a variety of sophisticated instruments.

Facilitator's Note: Juno will use sophisticated instruments, such as a microwave radiometer and magnetometer. For more information about the instruments onboard the Juno spacecraft, visit

Invite the children to pop their balloons to test their hypotheses (outside if there is water or whipped cream in any balloon).

Share with the children that scientists can never see exactly what is a planet or how its inside materials are arranged. Scientists cannot "pop" the planet to see if they are right! Their interpretation is based on the evidence they gathered. Their interpretation may be altered in the future as more evidence is collected, or new instruments are created.

If possible, build on the children's knowledge by offering them a future Jupiter's Family Secrets activity. Ten-year-old children may wrap-up their investigations of Jupiter by attending the concluding activity, My Trip to Jupiter, where they create scrapbooks to document their own journeys into Jupiter's deepest mysteries! Invite children ages 11 to 13 to return for the next program and use some of these tools to investigate Neato-Magneto Planets!