Specific Heat Capacity (IGCSE)
Year 10 (IGCSE) 🌡️ Energy & Thermodynamics Calculate heat energy using Q = mcΔT in complex scenarios.
📊 Q = mcΔT: Advanced Problem Solving
At IGCSE, you need to handle multi-step problems — combining Q = mcΔT with other physics equations.
🌡️ Specific Heat Capacity
$$Q = mc\Delta T$$🔌 Multi-step example: A 500 W heater runs for 3 minutes, heating 1 kg of oil from 20°C to 50°C. Find the SHC of the oil.
Step 1: Q = P × t = 500 × 180 = 90,000 J
Step 2: c = Q ÷ (mΔT) = 90,000 ÷ (1 × 30) = 3000 J/kg°C
Step 1: Q = P × t = 500 × 180 = 90,000 J
Step 2: c = Q ÷ (mΔT) = 90,000 ÷ (1 × 30) = 3000 J/kg°C
⚖️ Mixing temperatures: 2 kg water at 80°C mixes with 3 kg at 20°C. Find final temperature T.
Heat lost = Heat gained: 2 × 4200 × (80−T) = 3 × 4200 × (T−20)
2(80−T) = 3(T−20) → 160−2T = 3T−60 → 220 = 5T → T = 44°C
Heat lost = Heat gained: 2 × 4200 × (80−T) = 3 × 4200 × (T−20)
2(80−T) = 3(T−20) → 160−2T = 3T−60 → 220 = 5T → T = 44°C
🧪 Measuring SHC in the Lab
The electrical method is the most common way to measure specific heat capacity in GCSE experiments.
🧪 Electrical Heating Method
$$Q_{\text{electrical}} = P \times t = V \times I \times t$$| 📝 Step | 🔬 Procedure |
|---|---|
| 1 | Weigh the block — record mass (m) |
| 2 | Insert heater and thermometer; record start temperature (T₁) |
| 3 | Switch on heater; record V, I, and time t |
| 4 | Record final temperature (T₂) |
| 5 | Calculate: c = VIt ÷ (m × ΔT) |
Real values of c will be slightly higher than the true value because some heat is always lost to surroundings — an important source of experimental error!
🌊 Why Water Has Such a High SHC
Water's SHC (4200 J/kg°C) is unusually high because of hydrogen bonds between molecules.
🌍 Coastal vs. inland climates: Coastal cities (London, Sydney) have milder temperatures year-round. Inland cities (Moscow, Chicago) have extreme seasons. Reason: the ocean's high SHC acts as a giant temperature buffer!
🚗 Engine coolant: Water-antifreeze mixture circulates through engines. The high SHC of water carries away huge amounts of thermal energy safely.
Ready to test yourself? Click the Quiz tab above to answer questions on this topic!
🌡️ SHC Advanced Calculator