Lesson 1 • Solid, liquid or gas?

This lesson introduces the unit context and content: exploring solids, liquids and gases, the scientific theory that explains their behaviour (the particle model), and the substances that are sometimes difficult to categorise.

Communicating matters

View Sequence overview

Students will:

  • demonstrate curiosity and ask questions about substances that are difficult to classify as solid, liquid or gas.
  • classify substances as solid, liquid or gas.


Students will represent their understanding as they:

  • participate in class discussions about solids, liquids and gases.
  • create a diagrammatic and written explanation of what’s ‘inside’ materials/substances.