Heavyweight Champion: Jupiter
Heavyweight Champion: Jupiter! is a 30-minute activity in which children confront their perceptions of gravity in the solar system. The children weigh themselves on scales modified to represent their weights on other worlds to explore the concept of gravity and its relationship to weight. They consider how their weights would be the highest of all the planets while standing on Jupiter, but their mass remains the same no matter where in the solar system they are! They compare the features of different planets to determine which characteristics cause a planet to have more or less gravity.
This activity should be conducted before The Pull of the Planets in order for the children to better understand gravity before they model it. These concepts involve more advanced science than previous activities in Jupiter's Family Secrets, and they explore more deeply the science of the Juno mission and the rich information it will return to us. Facilitators who choose to undertake this activity should have a firm grasp of the scientific basis so that misconceptions are not introduced to the children.
What's the Point?
For each group of 10 to 20:
- Computer and projector to show a brief movie of an astronaut walking on the Moon, such as Moon Walk
- 3–9 "solar system scales," prepared as described under "Preparation" using:
- 3–9 bathroom scales with dials (not digital)
- Thin black marker
- Solar System Scales Guide
- 3–9 posters (one for each "solar system scale"), prepared as described under "Preparation" using:
- Brightly colored poster board
- Thick marker
- Family Portrait...in Numbers
- Optional: 1 set of Our Solar System lithographs (NASA educational product number LS-2013-07-003-HQ), preferably double-sided and in color
- His/her My Trip to Jupiter Journal or just the relevant "Heavyweight Champion: Jupiter!" page
- 1 pencil or pen
- Review the complete background information and the Facilitator's Guide to Gravity.
- Select the number of scales to offer and which planets you'd like to feature. It is not necessary to provide a scale for every planet, but we recommend offering at least three, including Earth and Jupiter.
Caution: Offer a Saturn scale ONLY to advanced audiences who are prepared to tackle the high–level concepts broached by this "trick" planet.
1. Ask the children to consider what it would be like to explore other worlds in our solar system.
- Would they experience gravity on other planets and our Moon? How could we find out? Accept all answers.
- Do we experience gravity on Earth? How?It holds us to Earth's surface.
Optional: Invite the children to jump and test this principle for themselves.
2. Play one or more movies of an astronaut walking on the Moon and assess their opinions.
- Now what do they think: Does the Moon have gravity? Yes.
- Does it have the same amount of gravity as Earth? Less.
- Which planet characteristics cause a planet to have more or less gravity? Consider the following variables: presence of an atmosphere, planet diameter, planet mass, planet temperature, and/or distance from the Sun. Which do they think is most important in determining a planet's gravitational strength? Accept all answers.
Invite the children to write their hypotheses in their journals.
Facilitator's Note: There are many different misconceptions about gravity; children may think that it is related to an object's motion, proximity to Earth or the Sun, temperature, magnetic field, atmosphere, or other unrelated concepts. Guide conversations cautiously and listen carefully to what the children say to avoid supporting their misconceptions.
3. Discuss the concepts of weight and gravity.
4. Invite the children to test how much they would weigh on other planets! Ask them to weigh themselves on the scales you modified to see what effect each planet's gravity would have on their weights. In their journals, invite them to record their measurements for each scale. In addition, ask them to note the characteristics for each of those planets.
- On which planet did they weigh the most? Jupiter.
- What do the children think it would feel like to weigh that much? Have they ever carried a 100–lb. backpack? What would it be like to feel that kind of weight not only on your back, but your hands, legs, feet, and head?
- On which planet did they weigh the least?
- How high do they think they could jump on that planet?
- On which planet did the children have the most mass? The least? Trick question! Remind the children of their discussions during Dunking the Planets. While their weights varied, the children had the same mass on every planet.
Facilitator's Note: If you have a Saturn scale, they might notice that they weigh about the same on Saturn and Earth, because Saturn's gravitational pull is about the same as Earth's at its cloudtops (which are far above the planet's bulky — and gravitationally strong — center). Because the force of gravity depends on both mass and distance, planets that are less dense have less gravity at their cloud-tops or surfaces, which are far above the bulk of the mass in their interiors. This is why planets like Saturn appear to have less gravity than Neptune, despite Saturn's greater mass. You may need to remind the children of what they learned in Dunking the Planets in order for them to understand these difficult concepts.
You may also find that different sources report a range of weights/gravity for both Jupiter and Saturn. The point of this activity is simply to gather the sense that the children would weigh different amounts on the different planets, which can be seen regardless of which source is used to define the weight on the planets.
5. Invite the children to consider the planet properties they discovered in Jump Start: Jupiter and recorded in their journals. Alternatively, ask them to research planet properties in books or consider a copy of Family Portrait...in Numbers. Allow them time to consider the hypotheses presented in their journals and form their own conclusions.
Invite the children to share their conclusions about the gravity in the solar system.
- Everyone weighed the most on Jupiter; in other words, Jupiter had the strongest gravitational pull of all the planets. What properties make Jupiter the heavyweight champion? Jupiter has the greatest mass and size of all the planets.
- What allowed Jupiter to beat out Saturn, a close contender in size? Jupiter is more dense than Saturn; it has more mass for its size.
- What planets are not even contenders? Why? The inner planets are all much smaller and have much less mass than the giant planets.
- Which planet would the children like to visit someday? Would they be able to jump higher or lower there?
- Would they want to visit Jupiter? What kind of gravity will the Juno spacecraft experience as it approaches and orbits Jupiter? Juno will experience a strong gravitational pull.