Grade 3 · Science · Lesson 18

States of Matter in Action

All the material around us is made of matter. Matter exists in three main states: solid, liquid, and gas. The state of matter depends on how the tiny particles (atoms and molecules) inside it are arranged and how much they move.

What this lesson teaches

1Describe the three states of matter and their key properties
2Classify everyday materials as solid, liquid, or gas
3Explain how matter changes state when heated or cooled

Free · 7 days · No credit card

Unlock the full HSEA system for 7 days.

Create a kid profile, open any lesson, save progress — your family uses HSEA exactly the way a paying family does. Cancel anytime. Nothing to set up, no card required.

✓ All 1,680 lessons, Grades 1–6, every subject
✓ Profiles + saved progress for every kid
✓ Final exams + printable certificates

Start your 7-day free trial →

Already convinced? See full membership plans →