Explore the three states of matter, how substances change state, and the particle model that explains why.
Matter exists as a solid, liquid, or gas. Solids have a fixed shape and volume; liquids have a fixed volume but take the shape of their container; gases have neither fixed shape nor fixed volume.
Classify ice, water, and steam by state.
Ice is solid, water is liquid, steam is gas — all the same substance (H₂O) in different states
Why does a gas fill its entire container, unlike a liquid?
Gas particles move freely and rapidly with large spaces between them, so they spread out to fill any available space
Classify a rock, cooking oil, and helium in a balloon by state.
Rock is solid, cooking oil is liquid, helium is gas
Matter changes state through melting (solid to liquid), boiling/vaporisation (liquid to gas), freezing (liquid to solid), and condensation (gas to liquid).
What is the change from solid directly to gas called?
Sublimation (e.g., dry ice/solid carbon dioxide)
Why does water vapour form droplets on a cold glass of juice?
The water vapour in the air condenses into liquid when it touches the cold surface
What is it called when a gas changes directly to a solid, skipping the liquid state?
Deposition (the reverse of sublimation)
1. Name the three states of matter.
2. What is the process called when a solid changes to a liquid?
3. What is the process called when a liquid changes to a gas?
4. What is the process called when a gas changes to a liquid?
5. Give an example of sublimation.
6. Classify wood, milk, and oxygen by state.
7. What is the process called when a liquid changes to a solid?
8. What is the process called when a solid changes directly to a gas?
9. Why does a solid keep its shape when moved to a new container, unlike a liquid?
10. Give an everyday example of condensation.