BTEC L3 EXTENDED DIPLOMA IN APPLIED SCIENCE
Unit 2: Practical Scientific Procedures and
Techniques
Assignment 2B: Undertake calorimetry to study cooling
curves
Thermometers and its calibration
Introduction
Importance of calibrating thermometers before undertaking an investigation
It is important to calibrate thermometers beforehand as it determines the
accuracy and quality of temperatures produced by thermometers. As
thermometers are used over long periods of time, the accuracy of results may
shift especially when using technologies, hence why calibration is necessary for
thermometers. To make sure that the temperatures we are producing are both
accurate and reliable, we need to continuously calibrate thermometers before we
carry out experiments.
The use of calibrating thermometers is to reduce any uncertainties in
temperatures obtained by establishing the accuracy of thermometers used.
Therefore, calibration is important as it allows us to control any
errors/uncertainties that may be present within measurements.
Benefits and limitations of alcohol/digital thermometers
Benefits of using digital Limitations of using digital
thermometers thermometers
Temperatures can be read quickly and Batteries in thermometer can die so
accurately need to be replaced from time to time
Small and portable Must be cleaned after each use
Most accurate reading of all Prone to interference with readings,
thermometer types e.g. food, drink
Benefits of using alcohol Limitations of using alcohol
thermometers thermometers
Freezes at -115˚Celsius so is Can be difficult to be seen as it is
appropriate for low temperatures transparent
Expands greater than other Thermometer always clings to the side
thermometer types of the tube
Thread may tend to break
Equipment list
- Bunsen burner
- Heatproof mat
- Gauze
- Tripod
- Ice
- Distilled water
- Beakers
1
, H.
BTEC L3 EXTENDED DIPLOMA IN APPLIED SCIENCE
Unit 2: Practical Scientific Procedures and
Techniques
- Digital thermometer
- Liquid thermometer
Risk assessment
Hazard Risk Control
Glassware, e.g. beaker Could break and cut you Keep away from edge of
surface
Hair Could get caught in Tie hair up
solution
Boiling water Could burn skin and Wear eye protection, if
eyes caught in eyes/skin,
flood eyes/skin with
water and seek medical
advice if necessary
Bunsen burner Could cause a fire Make sure to keep on
the safety flame, and if a
fire occurs, use a fire
blanket/heat-resistant
mat to cover and seek
medical assistance if
burns arise. Also, place a
heatproof mat
underneath the Bunsen
burner to avoid the risk
of a fire.
Water Could spill leading to If spilled, clean with
injury paper and dry
Lanyards Could get caught in Make sure to remove
solution
Method of calibration
Firstly, fill a beaker with water and put a few ice cubes in the water
(as shown in Figure 1) – make sure not to add too much water as this
could lead to the temperature taking longer to reach 0 ˚ C therefore
affecting the accuracy of your results. For example, I waited until there
was a steady temperature as this was the temperature at which there was a
Figure 1 – Image of thermometers
change in state.
being calibrated using icey water
Next, as soon as you have filled the beaker with ice and water, place a
digital/liquid thermometer in the water and leave the temperature to
settle for 1-2 mins. After 1-2 mins, record the temperature the water is at,
using the thermometer, and record 2 additional readings so that you can
calculate an average of the temperature reached. Repeat this for the
calibration of the other thermometer, e.g. digital/liquid.
Following this, fill a beaker with hot water and set up a Bunsen burner
(refer to Figure 2 for additional guidance) so that the water boils in the
beaker – make sure that when using the Bunsen burner, it is set as the safety
2