This key facts covers Two Types of Latent Heat within Specific Latent Heat for GCSE Physics. Revise Specific Latent Heat in Particle Model for GCSE Physics with 13 exam-style questions and 30 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 4 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 4 of 12
Practice
13 questions
Recall
30 flashcards
📚 Two Types of Latent Heat
Specific Latent Heat of FUSION (Lf):
- Energy to change between solid ↔ liquid (melting/freezing)
- For water: Lf = 334,000 J/kg
- "Fusion" = fusing/joining (particles come together when freezing)
Specific Latent Heat of VAPORISATION (Lv):
- Energy to change between liquid ↔ gas (boiling/condensing)
- For water: Lv = 2,260,000 J/kg
- MUCH bigger than fusion — particles must completely separate
Why Lv is much greater than Lf: Going solid → liquid only loosens bonds. Going liquid → gas completely breaks them. More bond-breaking = more energy needed.
Quick Check: Calculate the energy needed to melt 2 kg of ice at 0°C. (Lf of water = 334,000 J/kg)
E = m × L = 2 × 334,000 = 668,000 J (668 kJ). This is the energy needed to break the bonds in ice — temperature stays at 0°C throughout.