Melting and Cooling Notes & Questions | Class 2 Chemistry | Drishti OS

Melting and Cooling

NCERT anchor

Looking Around 2 — activities like watching ice cream melt, or butter melting on hot roti, connect to Healthy Food and daily life.

What you'll learn

Melting happens when a solid gets warm and turns into a liquid.
Cooling can turn some liquids back into solids (like water freezing into ice).
Heat is needed to melt; cold is needed to freeze.

Key concepts

Verbal: Melting = solid → liquid (by heating). Freezing = liquid → solid (by cooling).

Symbolic: Ice (solid) --heat--> Water (liquid). Water (liquid) --cold--> Ice (solid).

Level 1 — Things that melt with heat

Ice, butter, chocolate, and candle wax melt when warmed.

Level 1 — Things that freeze with cold

Water freezes into ice in a freezer.

Level 1 — Examples around us

Solid melts to liquid	Where we see it
Ice → water	Ice cube left outside
Butter → oily liquid	Butter on a hot pan
Chocolate → soft liquid	Chocolate in warm hands

Level 2 — Can it go back?

Melted butter can be cooled to become solid again (in the fridge). Melted ice (water) can freeze again.

Level 2 — India

Ghee turns from solid to liquid on a warm day; it becomes solid again in cold winter.

Worked example

A chocolate bar is left in the sun. What happens, and why?

Step 1 — The sun's heat warms the chocolate.
Step 2 — Chocolate changes from solid to soft/liquid.
Step 3 — This is called **melting**.
Answer: The chocolate melts because of heat.

Common mistakes

Mistake	Why	Fix
Melting is the same as dissolving	Both look like "disappearing"	Melting = heat changes state; dissolving = mixing with liquid
Ice always stays solid	Not considering heat	Ice melts with heat
Melted things can never be solid again	Ignoring cooling	Many melted things can be frozen/cooled back

Quick check

What happens to an ice cube left on a table?
Name one solid that melts when heated.
What do we call it when a liquid turns back into a solid?

Stretch: Does chocolate melt faster in the sun or in a fridge? Why?

Revision tip: Watch an ice cube melt and describe the change in your own words.

Open the Practice tab for graded questions on Melting and Cooling.

Melting and Cooling