Cooling Curves
The aim of this practical is to investigate the cooling curves of two substances through a phase
change (freezing).
Method:
Firstly, 10g of stearic acid was weighed into a boiling tube and the mass was recorded. About 150cm 3
of tap water was placed into a beaker. The apparatus was set up by placing the beaker on top of a
tripod and a gauze, and clamping the boiling tube in place so that it is in the water, but not touching
the base of the beaker. A thermometer was placed into the stearic acid and the water was heated
until the stearic acid has turned from solid to liquid.
Whilst holding the clamp stand, the stearic acid tube was carefully lifted out of the beaker of water.
The stop clock had begun, and the temperature of the acid was noted. Using a suitable results table,
the temperature was recorded every minute, as the stearic acid cooled down, until it reached nearly
40C (this took approximately 40 minutes). We also noted on the results table the temperature at
which the stearic acid began to solidify.
The method was then repeated, but this time using paraffin wax.
Results:
Mass of Stearic Acid 10g
Mass of Paraffin Wax 10g
Time (minutes) Temperature of Substance (C)
Stearic Acid Paraffin Wax
0 73 73
1 64 64
2 63 59
3 62 58
4 62 58
5 62 58
6 62 58
7 61 58
8 61 58
9 61 57
10 61 57
11 61 57
12 61 57
13 61 56
14 61 56
15 61 55
16 61 55
17 61 54
18 61 54
19 61 53
20 61 52
21 60 51
The aim of this practical is to investigate the cooling curves of two substances through a phase
change (freezing).
Method:
Firstly, 10g of stearic acid was weighed into a boiling tube and the mass was recorded. About 150cm 3
of tap water was placed into a beaker. The apparatus was set up by placing the beaker on top of a
tripod and a gauze, and clamping the boiling tube in place so that it is in the water, but not touching
the base of the beaker. A thermometer was placed into the stearic acid and the water was heated
until the stearic acid has turned from solid to liquid.
Whilst holding the clamp stand, the stearic acid tube was carefully lifted out of the beaker of water.
The stop clock had begun, and the temperature of the acid was noted. Using a suitable results table,
the temperature was recorded every minute, as the stearic acid cooled down, until it reached nearly
40C (this took approximately 40 minutes). We also noted on the results table the temperature at
which the stearic acid began to solidify.
The method was then repeated, but this time using paraffin wax.
Results:
Mass of Stearic Acid 10g
Mass of Paraffin Wax 10g
Time (minutes) Temperature of Substance (C)
Stearic Acid Paraffin Wax
0 73 73
1 64 64
2 63 59
3 62 58
4 62 58
5 62 58
6 62 58
7 61 58
8 61 58
9 61 57
10 61 57
11 61 57
12 61 57
13 61 56
14 61 56
15 61 55
16 61 55
17 61 54
18 61 54
19 61 53
20 61 52
21 60 51
