Freezing

• Freezing is the change of a liquid into a solid when it loses heat (gets cold enough).
• Water freezes into ice; juice can be frozen into ice pops.
• Freezing is the opposite of melting — melting adds heat, freezing removes heat.
• Freezers keep foods like ice cream solid by keeping them very cold.

Level 1 — Core idea

Verbal: Put a tray of water in the freezer overnight, and by morning it has turned into hard ice — the cold took away its heat.

Symbolic: Liquid - heat -> solid (freezing).

Visual: Water in an ice tray starts as a clear liquid and turns into solid, cloudy-white ice cubes after freezing.

Level 2 — Going deeper

Freezing and melting are reverse changes of state between solid and liquid — one removes heat, the other adds heat.

NCERT anchor

NCERT Looking Around 3 — making ice at home, storing ice cream in the freezer.

What happens to water left in the freezer overnight?

Step 1 — The freezer removes heat from the water.
Step 2 — Without enough heat, the liquid water turns solid.
Answer: **It freezes into ice.**

Is freezing the same as melting?

Step 1 — Melting: solid to liquid (heat added).
Step 2 — Freezing: liquid to solid (heat removed).
Answer: **No**, they are opposite changes.

• What happens to water when it freezes?
• Is freezing the opposite of melting?
• Why do we keep ice cream in the freezer?
• Stretch: How can juice become an ice pop?

Revision tip: Remember: freezing = liquid to solid, always with heat removed (cooling).

Open the Practice tab for graded questions on Freezing.