Gravity's Pull: Why Everything Falls Toward Earth's Center
Shared by A STEM Educator
Students will construct a written CER argument explaining that Earth's gravitational force pulls all objects toward Earth's center of mass, using evidence from drop experiments and orbital mechanics to support their reasoning with Newton's law of universal gravitation.
Lesson Overview
Students investigate Earth's gravitational force by dropping objects, analyzing motion data, and examining how gravity pulls toward Earth's center of mass — not just 'down.' They build a CER argument connecting satellite orbits and space station design to gravitational principles.
Materials
- Inflatable globe or beach ball (globe model)
- Small objects of varying mass: eraser, marble, crumpled paper, coin
- Meter stick or tape measure
- Motion sensor or slow-motion phone camera (optional)
- Printed globe diagram (for arrow-drawing activity)
- Sticky notes
- Whiteboard markers
- CER writing frame handout
- Four-Quadrant note sheet (printed)
Scaffolded Task Progression
[ Interactive graph / diagram — available in the full lesson ]
Draw an arrow FROM each person showing the direction gravity pulls them. Then write your initial claim: Does gravity pull everyone toward the same point, or in different directions?
Use the CER starter: *I claim that gravity pulls objects toward _____ because _____.*
Write a claim sentence AND sketch a simple diagram showing what you think gravity 'cares about' when pulling objects on Earth's surface.
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