The phase change of wax
Determining the melting point of candlewax
Principle:
The melting point of candlewax is the temperature at which:
1. The solid material turns to liquid (by heating it up).
2. The liquid turns to solid (by cooling it down).
You are now going to investigate what happens to the temperature if you cool down candlewax.
Research question:
What is the flow from the cooling curve of wax?
Hypothesis:
How do you think the graph will look like?
Make a draft of it here.
Theory:
Which theory do you need for this from your study book?
Requirements:
Test tube with 1.5 cm candlewax
Test tube rack
Gas burner (Bunsen burner) with tripod
and gas
Erlenmeyer or beaker
Thermometer
Stopwatch
Clips
Method:
1. Note down everything that you observe (smell, colour and what you see).
2. Fill the glass (here the erlenmeyer) with 200 mL water.
3. Heat up the water until all the wax has melted and the water
temperature is around 90 °C.
4. Take the test tube with the wax out of the water and put it in the test tube rack.
Place the thermometer in the wax and put the test tube in the rack.
5. Measure the temperature every 30 sec. and note it down in a chart.
6. Draw a graph showing temperature against time and determine the melting point.
Observations:
What have you observed?
Conclusion:
What conclusion (s) can you draw from your research?
Discussion:
What have you learned and why does/doesn’t this deviate from your hypothesis?
t in s
T in ⁰C
0
30
60
Etc.
