6.MS-PS2-4MA STE 6.MS-PS2-4: Use evidence to support the claim that gravitational forces between objects are attractive and only noticeable when one or both objects have very large mass. MS-ESS1-2MA STE MS-ESS1-2: Develop and use a model to describe the role of gravity in the motions within galaxies and the solar system. SEP-2NGSS SEP-2: Developing and Using Models — students build and test mental models of gravity wells and orbital motion. SEP-6NGSS SEP-6: Constructing Explanations — students synthesize evidence from the simulation to explain why planets orbit rather than crash or escape.
Phenomenon-FirstStudents encounter the orbiting-vs-crashing phenomenon before receiving formal explanation, activating prior knowledge and curiosity (Bransford et al., 2000). Spatial ReasoningInteractive spacetime grid visualization builds spatial mental models of gravitational fields (Newcombe, 2010). Productive ExplorationTrial-and-error orbit launching creates productive struggle that deepens conceptual encoding (Kapur, 2016). Retrieval PracticeEnd-of-simulation quiz prompts active retrieval of concepts, strengthening long-term retention (Roediger & Butler, 2011).
Simulation

Gravity Wells

Explore how mass, gravity, and motion work together to create orbits. Build gravity wells, launch objects into space, and discover why planets do not simply fly away or crash into the Sun.

Before You Begin
Read this first, then investigate

This is a four-step investigation into gravity, mass, and orbital motion. Complete each step in order.

Common Misconception

Gravity does not only pull things straight down. Gravity pulls objects toward the center of mass. In space, this pull can bend an object's path into an orbit — the object is constantly falling, but also moving forward fast enough to keep missing the mass.

What is this simulation showing?

Students test how mass changes the shape of a gravity well and how moving objects respond to that pull. Imagine spacetime as a rubber sheet — a massive object pushes the sheet downward, and nearby objects roll toward the depression.

Why do objects orbit?

An orbit happens when forward motion and gravity are balanced. The object is constantly falling toward the massive body, but also moving forward fast enough to keep missing it. Too slow: crash. Too fast: escape. Just right: orbit.

① Mass
② Build Well
③ Launch Orbit
④ Quiz
Phase 1
Gravity and Motion Concepts
Unlock all three gravity concepts to reveal how mass, gravity, and motion work together. Each one tells a different part of the story.
✓
Low Mass
🌙
A small object creates a shallow gravity well. Its pull is weaker and affects nearby objects less strongly — like a golf ball resting on a trampoline.
✓
High Mass
☀️
A massive object creates a deeper gravity well. Its stronger pull can bend paths into orbit across enormous distances — like a bowling ball warping a trampoline sheet.
✓
Motion Matters
🚀
Gravity alone does not make an orbit. An object also needs sideways motion. Too slow means crash. Too fast means escape. The right balance creates a stable orbit.
Why this matters