PHY032 · Thermodynamics · Classes 9–12
Specific heat capacity
Objective: To find the specific heat capacity of a substance using an electric heater and a calorimeter.
🧰 Apparatus
- Insulated calorimeter
- Low-voltage immersion heater (12 V)
- Joulemeter or ammeter + voltmeter + stopclock
- Thermometer
- Balance
📐 Formulas and SI units
Q = m c ΔT (J)
Q = VIt for an electric heater
💡 Theory
Specific heat capacity c is the energy needed to raise 1 kg of a substance by 1 K: Q = mcΔT. Water has a very high c (4200 J/kg K), so it warms slowly and stores a lot of heat; metals warm quickly.
🪜 Procedure
- Measure the mass of the water (or metal block).
- Record the starting temperature.
- Switch on the heater and record the energy supplied (VIt).
- Stir and record the highest temperature reached.
- Calculate c = Q/(mΔT).
📋 Observations Simulated values
✅ Result and conclusion
42 kJ raises 1 kg of water by 10 °C; the same energy would raise 1 kg of copper by about 109 °C.
🔬 In a real lab
Heat leaks to the surroundings and warms the calorimeter, so the measured c is a little high.
⚠️ Safety
Use only a low-voltage heater; never switch it on out of liquid. Hot water and blocks burn: handle with tongs.
❓ Quick check
1. Which warms fastest with the same heat?
2. Unit of specific heat capacity?
3. Coastal cities have milder climates because water has…
🏋️ Practice
EasyHeat to warm 2 kg water by 5 °C?
Answer: 42 kJ
Medium900 J warms 0.1 kg aluminium by?
Answer: 10 °C
ChallengeWhy is water used in car radiators?
Answer: High c carries away lots of heat