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Summary All Criteria BTEC Level 3 Unit 2 Assignment 2
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Practical Scientific Procedures and Techniques assignment 2 Calorimetry all criteria and distinction received.
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Unit 2 Assignment 2 ‘Calorimetry’ Moreen MeroCalibration of thermometers:
The aim of this experiment is to calibrate an alcohol thermometer and a digital thermometer.
Boiling water and ice water were used as fixed points.
Risk assessment: Mercury : a hazardous substance, any broken thermometers must be reported
to the teacher, and cleaning must be carried by lab technicians.
Boiling water: being aware of the water when it boils, and being aware of the beaker itself as
it is also hot.
Broken glasses: being extreme careful with the thermometers, as they are fragile, they can
easily break.
How the experiment was carried out:
Lower fixed point : A beaker filled with ace and distilled water was set, an ungraduated
alcohol thermometer was hold in the ice, until it is steady, without touching the glass of the
beaker. The position of the alcohol column on the thermometer was marked with a pen. This
was repeated using different thermometers; graduated liquid thermometer, and digital
thermometer.
Upper fixed point: Bunsen burner, tripod and gauze was set. A beaker of distilled water was heated
and gently boiled. An ungraduated alcohol thermometer was carefully put in the boiling water, without
touching the glass of the beaker. Until the alcohol column is steady, the position of the alcohol column
of the thermometer was marked with a pen. This was repeated using different thermometers;
graduated liquid thermometer, and digital thermometer.
The alcohol thermometer was used to measure the Temperature of the water-bath
temperature of the water bath, and the temperature of the
water in the water bath was estimated after marking its
scale on the thermometer.
Lower fixed point Upper fixed point
Temperature of
temperature temperature
The water bath temperature was estimated based on the the lab 24 ℃
barked area on the thermometer, where the alcohol was stable. The estimated temperature for
the water bath was 39 ℃, this was based on some factors. As the marked area shows that the
temperature in closer to the lower fixed point temperature, which is 0 ℃. Which means the water bath
temperature is not higher that 50 ℃. Other factor is that the temperature of the room was estimated
between 23-25 , and it is close to the water bath temperature marked, which indicates that the
temperature of the water bath might be between 39-40 ℃.
Results table for calibration of thermometers showing temperature recorded
The thermometer Lower fixed point Upper fixed point
temperature recorded temperature recorded
Alcohol in glass thermometer 0℃ 100 ℃
Digital thermometer 0℃ 100 ℃
, Unit 2 Assignment 2 ‘Calorimetry’ Moreen Mero
How accurate the thermometers were found: the alcohol in glass thermometer was quite
accurate, as the temperature that was recorded for the lower fixed point was 0 ℃, and for the
upper fixed point was 100 ℃, but this does not prove that these temperatures were accurate, as the
thermometer was ungraduated without scales. The temperature was recorded when it was steady and
stable as certain point. Which indicates the temperature of what was measured. For the ice water, the
thermometer was fixed inside the beaker without touching the glass of the beaker, so it can read the
temperature of the ice only, which must be carried quickly before the ice melts, and therefore it will not
be accurate enough for the lower fixed point temperature. For the boiling water temperature, same
procedures were followed, as soon was the water boils, the thermometer was fixed inside the beaker
without touching the glass, which obviously will not be accurate to record, as it could lead to breaks in
the thermometer and cause error. So the thermometer must only read the temperature of the boiling
water, to get accurate lower fixed point temperature. For the digital thermometer, the temperature was
more accurate, as it shows the exact temperature on its screen. Bit also is has some errors, as it showed
0.3 ℃ for the lower fixed point, which is 0 ℃ in essence. But this indicates some inaccuracy. For
example, the thermometer might have not been steady in the ice, or the accrual thermometer might have
errors in reading accurately. The same issue for the boiling water, as it showed 100.7 ℃, which could
be cause of the same issue, or maybe the thermometer touched the glass of the beaker, which was
basically hotter than the water. however, the temperature would must show 100 ℃ for the boiling water,
and 0 ℃ for the ice as a high accuracy, which it was quite measured with the thermometers.
Finding cooling curve:
The aim of this experiment is how to monitor the temperature of a certain substance as it cools down
from liquid form to solid.
Risk assessment: No specific hazard is linked with the solid wax. Hot water must be handled with
extreme care.
How the experiment was carried out:
Stearic acid was melted in a boiling tube using the water bath. While the wax is melting, a setup of
clamps and stand was carried out, so the boiling tube of the melted wax inside will be held with the
thermometer inside it accurately, to allow the thermometer to be fixed steadily in the wax of stearic
acid, and not touching the glass of the boiling tube. The clamps will be adjusted to hold the boiling tube,
and the thermometer in a steady and accurate way, so the thermometer will read the temperature of the
wax accurately with no factors affecting it, such as the glass of the boiling tube, or the clamps
adjustment. Once the boiling tube is adjusted along with the thermometer, a timer was started, and each
minute, the temperature of the wax was recorded, till it reaches 50 ℃.
A trial experiment was carried out, and then the actual experiment. In the actual experiment, the timing
for the recording stopped as the temperature of the wax reached 48 ℃. And in both experiments, the
temperature was recorded every minute. The recording number changed as to improve the cooling
curve, and see how the temperature rate changes, or it will stay at the same rate. The time between each
recording was kept at 1 minute, is it gives accurate reading, and significant change to the temperature
between each minute. The second experiment was carried more independently and based on each
student’s decision on the way they handle the experiment. In the first experiment, the wax powder was
boiled, and then used to record the temperature as it cools down and become solid. And in the second
experiment, the wax powder was boiled and ready, for the temperature to be recorded.
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