Changing States – Melting and Freezing

📚 Key Concepts

🔹 How Do States Change?

Heating Effects:

  • Ice → Water: Melting (solid to liquid)
  • Water → Vapour: Evaporation (liquid to gas)

Cooling Effects:

  • Vapour → Water: Condensation (gas to liquid)
  • Water → Ice: Freezing (liquid to solid)
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🔹 State Change Processes

1. Melting

  • Conversion of solid to liquid
  • Requires heat energy
  • Examples: Ice melting, candle wax melting, butter melting

2. Freezing

  • Conversion of liquid to solid
  • Releases heat energy
  • Examples: Water freezing to ice, wax solidifying

3. Evaporation

  • Conversion of liquid to gas
  • Requires heat energy
  • Happens at surface at all temperatures

4. Condensation

  • Conversion of gas to liquid
  • Releases heat energy
  • Happens when gas is cooled

🔹 Other Substances That Change States

Examples:

  • Candle wax: Solid → Liquid → Solid
  • Coconut oil: Liquid in summer → Solid in winter
  • Ghee: Solid when cool → Liquid when heated
  • Chocolate: Solid → Liquid when heated