The Edexcel core practical on the properties of water: a temperature-time graph for melting ice, the specific heat capacity of water, and the funnel method for the latent heat of fusion.
What you will learn
- Write a 6-mark method for a temperature-time graph of melting ice
- Read the melting point and melting time from the graph and explain the flat part
- Calculate the specific heat capacity of water and the specific latent heat of fusion from results
- Say whether a mistake makes the result too big or too small
Melting ice, step by step
Fill a beaker with crushed ice straight from the freezer and push a thermometer (or a temperature probe) into the middle.
Record the temperature, then heat gently and steadily, stirring all the time, and read the temperature every 30 seconds. Keep going until all the ice has melted and the water has reached about 20 °C.
- Crushed ice packs round the thermometer, so it reads the ice and not the air.
- Stirring keeps the whole mixture at one temperature.
Safety: hot plates stay hot long after they look cold, so let them cool before you touch them. Keep water well away from mains sockets, and stir with a stirring rod, never with a glass thermometer. Use a low-voltage heater, switch it on only when it is covered by water or ice (out of water it overheats), and clamp the beaker or stand it on a stable heatproof mat so it cannot tip over.
The rest of this lesson and its 9 practice questions are locked.
In this lesson
- Melting ice, step by step
- The graph
- Two values from your results
- Try it: Why each step?
9 practice questions, marked as you go; about 25 minutes in all.
Key terms
Stirring all the time, Less steeply
In this unit: Particle model, density and gas pressure
Density and its required practical, changes of state, specific latent heat, and the particle model of gas pressure, including p₁V₁ = p₂V₂.