--- title: "The Particle Model" description: "Use the particle model to explain the properties of solids, liquids, and gases, including differences in arrangement, movement, and spacing, and apply the model to explain density, compressibility, an" canonical: https://lightmysky.com/learn/science/the-particle-model-mt_b6kZgqolEd source: https://lightmysky.com/learn/science/the-particle-model-mt_b6kZgqolEd.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # The Particle Model Use the particle model to explain the properties of solids, liquids, and gases, including differences in arrangement, movement, and spacing, and apply the model to explain density, compressibility, and the anomalous expansion of water Subject: Science · Area: Matter & Materials · Ages 11 to 12 Page: https://lightmysky.com/learn/science/the-particle-model-mt_b6kZgqolEd ## Ready when they can - Draws particle diagrams for solids, liquids, and gases showing correct arrangement and spacing - Explains why gases are compressible but liquids and solids are not - Explains why ice floats on water using the anomalous expansion of water - Uses particle spacing to explain why gases are much less dense than solids and liquids ## Lesson: Squashing Gases and Floating Ice You already know solids, liquids, and gases are made of tiny moving particles, and that gas particles are spread far apart while solid particles are packed close together. Now let's use that to explain why some things squash easily and others don't, why gases weigh so little for their size, and why ice floats instead of sinking. *(drawing: A gas has far fewer particles in the same size box than a solid. All that empty space is why gases squash easily and weigh so little for their size.)* Squashing means pushing particles closer together. Gas particles start far apart, so there's plenty of empty space to push into, and the gas squashes easily. Liquid and solid particles are already touching, so there's no space left. That's why you can't squash a liquid or a solid, no matter how hard you push. **Example.** Mia squeezes a balloon full of air and it flattens easily, because the air particles inside are spread apart and simply move closer together. She then tries to squeeze a bottle full of water with no air inside, and it barely changes shape at all, because the water particles are already touching and have nowhere left to go. Here's something odd about water: when it freezes, its particles lock into a pattern with more space between them, not less. That extra space makes ice less dense than liquid water, so instead of sinking, ice floats on top. **Recap.** How closely particles are packed decides whether something squashes, how dense it is, and why ice floats instead of sinking. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Drawing Particle Diagrams](https://lightmysky.com/learn/science/drawing-particle-diagrams-mt_htAYR-iCFF) - [Matter Is Made of Particles](https://lightmysky.com/learn/science/matter-is-made-of-particles-mt_ylruY6VhOf) - [Solids, Liquids & Gases](https://lightmysky.com/learn/science/solids-liquids-and-gases-mt_YQkUdIHO8L) ## Opens up - [Physical vs Chemical Changes](https://lightmysky.com/learn/science/physical-vs-chemical-changes-mt_1hgck6ucII) - [How Materials Change State](https://lightmysky.com/learn/science/how-materials-change-state-mt_CyV7crZ8hl) - [The Gas Laws and the Ideal Gas Equation](https://lightmysky.com/learn/science/the-gas-laws-and-the-ideal-gas-equation-mt_G7DOTVl4KM) - [Density and How to Measure It](https://lightmysky.com/learn/science/density-and-how-to-measure-it-mt_HrKI1-UzfI) - [Conduction, convection, and radiation](https://lightmysky.com/learn/science/conduction-convection-and-radiation-mt_ySnOkVIu22) - [Atoms, Elements & Compounds](https://lightmysky.com/learn/science/atoms-elements-and-compounds-mt_Z_Wu_77ybI)