Core practical: specific heat capacity and melting ice

1. Put a known mass of water in an insulated beaker.
2. Heat it with an electric immersion heater. Measure the energy supplied with a joulemeter, or use a voltmeter, ammeter and stopwatch: E = I × V × t.
3. Record the temperature rise with a thermometer, stirring the water.
4. c = ΔQ ÷ (m × Δθ)
Insulate the beaker and use a lid to reduce energy lost to the surroundings. The measured value is usually a bit higher than the true value (4200 J/kg °C), because some energy heats the surroundings, not the water.

1. Put crushed ice (from a freezer, below 0 °C) in a beaker with a thermometer.
2. Heat gently (for example in a warm water bath), stirring, and record the temperature every 30 seconds.
3. Plot temperature against time.
The temperature rises to 0 °C, then stays flat while the ice melts, then rises again once all the ice has melted.

Heating a substance increases its internal energy. This either raises its temperature or changes its state, not both at once.
During melting, the energy breaks the bonds between particles (increasing their potential energy), not their kinetic energy, so the temperature stays constant. This energy is the latent heat.