Solids, Liquids & Gases
Compare and group materials as solids, liquids, or gases based on their observable properties and behaviour
What a learner can do afterwards
- Define solids (fixed shape, hard to compress), liquids (flow, take shape of container), gases (spread out, fill space)
- Sort at least eight everyday materials into solid, liquid, or gas categories
- Explain tricky cases like sand (solid particles) or steam (gas, not visible water droplets)
1 · Read
You already know solids, liquids, and gases by name. Today you compare how each one behaves and practice sorting real things into the right group, even some tricky ones.
Mia sorts things on the table. A rock keeps its shape and feels hard, so it is a solid. Orange juice flows to fit its glass, so it is a liquid. Air from a fan spreads out unseen, so it is a gas. She groups by behavior, not looks.
Three tricky cases. Sand pours, but each grain keeps its shape, so sand is a solid made of many pieces. Steam is a gas you cannot see. The white cloud above the kettle is tiny liquid droplets, not the gas. Toothpaste sits between the rules: it keeps its squeezed shape but flows under pressure, so it sorts closest to liquids.
Solids keep their shape, liquids flow to fit their container, and gases spread out to fully fill it, so sort by how each one behaves, not just how it looks.
The rewritten readings were written for this dataset.
2 · Watch
Take it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.