Gravity and orbits model: a 6–8 stretchy fabric activity
What it is: a middle school model where stretchy fabric pulled tight over a large bowl or hoop dips under a heavy ball (the Sun). Marbles rolled around the dip curve and circle, a little like planets in orbit. Students describe how a bigger mass makes a deeper well and also discuss what the model gets wrong.
Time: about 40 minutes. Grade: 6–8.
Materials: a piece of stretchy fabric (an old T-shirt or a stretchy sheet), a large mixing bowl, embroidery hoop or laundry basket to stretch it over, binder clips or tape, a heavy ball about the size of an orange, a lighter ball the same size, and several marbles.
- Stretch the fabric tight over the bowl and clip it. Roll a marble across: it goes straight.
- Place the heavy ball in the middle. Ask: "What changed?" Roll the marble straight past the dip and watch it curve.
- Students try to roll a marble so it circles the Sun at least twice. Ask: "What speed works? What happens if it is too slow or too fast?"
- Swap to the lighter ball. Compare how deep the dip is and how much marbles curve.
- Discuss the limits: the marbles slow down from friction and spiral in, but real planets do not lose speed that way, which is why they keep orbiting for billions of years.
- Students write two ways the model is like the solar system and one way it is not.
Safety: keep marbles on the table with a tray around the model, and pick them up right away so no one slips.
Differentiation: students who need support focus on what changed when the heavy ball was added. Students who are ready time orbits for marbles started close to and far from the Sun and compare. English learners can use "The model is like / not like space because ___."
Quick check: ask: "Why does a marble that is moving too slowly fall into the Sun in this model?"
For more ideas at this grade, browse the other free activities on the Hub.
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About this resource
- Shared by
- @UpOnlyLearning · Curriculum team
- Posted
- Oct 31, 2026
- Type
- Lesson plan
- Grade
- Grades 6–8
- Subject
- Science
- Language
- English
- License
- Free for classroom, co-op and tutoring use. Please don't resell.