Emilia Hawkins
Unit 2: Practical Scientific Procedures and Techniques
B: Undertake calorimetry to study cooling curves
Calibration of liquid and digital thermometers
Equipment
o Beaker
o Liquid thermometer
o Digital thermometer
o Stop clock
o Bunsen burner, tripod and gauze
o Heat resistant mat
o Crushed ice
Method for calibrating thermometers:
1. Fill a large beaker with crushed ice and top up with a small amount of tap water.
2. Stir with a glass rod and allow to stand for approximately three minutes.
3. Place the thermometer into the beaker, ensuring the sensor is fully immersed.
4. Take a reading after 30 seconds and note down the temperature measured. It should read
0oC.
1. Bring some water to the boil and pour into a large beaker.
2. Place the thermometer into the boiling water, holding it in the middle of the container.
3. Take a reading after 30 seconds and note down the temperature measured. It should read
100oC.
Calibrate liquid and digital thermometer
Results from calibration of liquid thermometer in iced water = 1 oC
Results from calibration of liquid thermometer in boiling water = 100 oC
Results from calibration of digital thermometer in iced water = 0.3 oC
Results from calibration of digital thermometer in boiling water = 100 oC
From the results of the calibration of both a liquid and digital thermometer, I found that the digital
thermometer was more accurate and this is illustrated above as the digital thermometer produced
results closer to my expectations than the liquid thermometer, e.g. the ice was closer to expected
0oC reading. This means that to measure the cooling curves for 2 solids I would use the digital
thermometer to eliminate the factor of human error when reading the values from the
thermometer. Also, the digital thermometer reads temperature to 1 decimal place, whereas the
, Emilia Hawkins
liquid thermometer can only be read to the nearest degree. By using a digital thermometer, it means
that my experiment can be repeated more easily because people might read a liquid thermometer
differently. Therefore making my results more reliable and accurate.
Investigating cooling curves for solids
Equipment
o Beaker
o Boiling tube
o Boiling rack
o Liquid thermometer
o Digital thermometer
o Stop clock
o Clamp, stand and boss
o Bunsen burner, tripod and gauze
o Heat resistant mat
o Stearic acid
o Paraffin wax
Method for cooling stearic acid / paraffin wax:
1. Using tongs, carefully lift the boiling tube from the water and place it into a boiling tube
rack.
2. Now measure an record the temperature every minute as the stearic acid / paraffin wax
cools.
3. Record the temperature at which you see the stearic acid / paraffin wax begin to solidify.
This is the melting temperature.
4. Record the temperature until it reached 35 oC.
Cooling stearic acid
Time (mins) Temperature (oC)
0 65.0
1 64.2
2 62.3
3 60.9
4 59.5
5 58.1
6 56.6
7 55.3
8 54.3
9 52.8
10 51.6
11 50.4
12 49.1
13 48.2
14 47.6
Unit 2: Practical Scientific Procedures and Techniques
B: Undertake calorimetry to study cooling curves
Calibration of liquid and digital thermometers
Equipment
o Beaker
o Liquid thermometer
o Digital thermometer
o Stop clock
o Bunsen burner, tripod and gauze
o Heat resistant mat
o Crushed ice
Method for calibrating thermometers:
1. Fill a large beaker with crushed ice and top up with a small amount of tap water.
2. Stir with a glass rod and allow to stand for approximately three minutes.
3. Place the thermometer into the beaker, ensuring the sensor is fully immersed.
4. Take a reading after 30 seconds and note down the temperature measured. It should read
0oC.
1. Bring some water to the boil and pour into a large beaker.
2. Place the thermometer into the boiling water, holding it in the middle of the container.
3. Take a reading after 30 seconds and note down the temperature measured. It should read
100oC.
Calibrate liquid and digital thermometer
Results from calibration of liquid thermometer in iced water = 1 oC
Results from calibration of liquid thermometer in boiling water = 100 oC
Results from calibration of digital thermometer in iced water = 0.3 oC
Results from calibration of digital thermometer in boiling water = 100 oC
From the results of the calibration of both a liquid and digital thermometer, I found that the digital
thermometer was more accurate and this is illustrated above as the digital thermometer produced
results closer to my expectations than the liquid thermometer, e.g. the ice was closer to expected
0oC reading. This means that to measure the cooling curves for 2 solids I would use the digital
thermometer to eliminate the factor of human error when reading the values from the
thermometer. Also, the digital thermometer reads temperature to 1 decimal place, whereas the
, Emilia Hawkins
liquid thermometer can only be read to the nearest degree. By using a digital thermometer, it means
that my experiment can be repeated more easily because people might read a liquid thermometer
differently. Therefore making my results more reliable and accurate.
Investigating cooling curves for solids
Equipment
o Beaker
o Boiling tube
o Boiling rack
o Liquid thermometer
o Digital thermometer
o Stop clock
o Clamp, stand and boss
o Bunsen burner, tripod and gauze
o Heat resistant mat
o Stearic acid
o Paraffin wax
Method for cooling stearic acid / paraffin wax:
1. Using tongs, carefully lift the boiling tube from the water and place it into a boiling tube
rack.
2. Now measure an record the temperature every minute as the stearic acid / paraffin wax
cools.
3. Record the temperature at which you see the stearic acid / paraffin wax begin to solidify.
This is the melting temperature.
4. Record the temperature until it reached 35 oC.
Cooling stearic acid
Time (mins) Temperature (oC)
0 65.0
1 64.2
2 62.3
3 60.9
4 59.5
5 58.1
6 56.6
7 55.3
8 54.3
9 52.8
10 51.6
11 50.4
12 49.1
13 48.2
14 47.6
