Marwa Afzal
Ms. Davies
Applied Science
Unit 2 Aim B
Introduction:
Calorimetry is used to measure the amount of heat released or absorbed
during a chemical reaction, transferred to or from a substance in a system.
We did this experiment to find the cooling of Stearic Acid and Paraffin Wax
against time.
Calibration of thermometers:
Method for Ice Water:
1. Fill a beaker with ice cubes and then add a bit of water into the beaker
2. Then, stir the water and leave to sit for 3 minutes on a timer and stir
3. After that, stir the water again and place the thermometer into the
beaker making sure the entire bulb is covered by the water
4. The temperature should then show as 0°C, if not then you must
measure the amount that the thermometer was off by and use this in
your results to get accurate results
Result:
Date Thermometer Temperatu Temperatu Temperatu Average
re of re of re of
boiling boiling boiling
water (°C) water (°C) water (°C)
19/9/23 Alcohol 5 4 4 4.3
19/9/23 Digital n/a (out of n/a n/a n/a
(clinical) range)
19/9/23 Digital (probe) -1.3 -0.7 -0.5 -0.8
Method for Boiling Water:
1. Fill a beaker with boiling water from the kettle.
2. Then, place the thermometer into the beaker and make sure the whole
bulb is submerged with the liquid.
3. Again, if the temperature does not show as 100°C you must measure
the amount the thermometer was off by and use that difference to get
accurate results.
Result:
,Marwa Afzal
Ms. Davies
Applied Science
Unit 2 Aim B
Date Thermometer Temperatu Temperatu Temperatu Average
re of re of re of
boiling boiling boiling
water (°C) water (°C) water (°C)
19/9/23 Alcohol 85 84 82 83.7
19/9/23 Digital n/a (out of n/a n/a n/a
(clinical) range)
19/9/23 Digital (probe) 98.1 97.9 98.3 98.1
Explanation of Results:
The results for the boiling water should have been 100°C for every result,
however there were multiple different results. Furthermore, the results for
the ice-cold water should have been 0°c each time. To improve the accuracy
of my results for stearic acid and paraffin wax I should calculate the
inaccuracy of the results for the calibration and use has been raised. For
example, on average the boiling water difference using the alcohol
thermometer was 83.7 so 100 – 83.7 = 16.4°C so when it comes to getting
my results for stearic acid and paraffin wax, I will add 16.4°C to get a more
precise result. Using the Digital Probe thermometer, the average
temperature was 98.1, so 100-98.1 = 1.9°C so this means when I get
my results, if the digital probe thermometer was used, I would have
to add 1.9°C. For the ice-cold water, I had to do -0.8 – 0 which gives
the difference of -0.8°C, so when finding my results through the
alcohol thermometer, I would need to subtract 0.8°C so that my
results stay accurate. However, when I used the alcohol
thermometer, when I get my results, I would need to subtract 4.3°C
from my results to gain a more precise value (4.3-0=4.3).
Evaluation of Thermometers:
I would say overall the best thermometer to use would be the digital probe
rather than the others, because not only was it the closest to the actual
results that I should’ve gotten but there’s also no chance of getting human
error, for example, not looking at the thermometer at eye level or having the
bulb of the thermometer always in the substance. Ultimately, if I did this
experiment again, I would use the Digital probe just because of its accuracy
and preciseness.
In school experiments, I found four main thermometers that can be safely
used in the school lab. These are:
, Marwa Afzal
Ms. Davies
Applied Science
Unit 2 Aim B
Mercury-in-glass thermometer – which is the one usually used in the
school labs, the mercury is contained in a sealed glass tube, the
temperature is read by the mercury moving in the tube and outside
there are marks with the different temperatures. However, this is not
as accurate as the person reading it may not be reading from eye level
which would cause the results to not be precise.
Infrared – a lens that focuses the infrared energy which it converts into
an electrical signal that displays into units of temperature. However,
this is only suitable to take temperatures from a distance rather than
up close which means it would not work well with my experiment.
Bimetallic strip – is made of two metals bonded together, used mostly
in industries to control temperatures, there is a strip which bends
towards the different metals of different temperatures. However, this is
not very accurate to get specific measurements so it would not be
suitable for my experiment.
Thermistor – electronic device resistance changes according to
temperature, measures electrical resistance changes and converts
them to temperature changes, which then shows the temperature with
the units. This is very accurate as it shows the exact temperature.
Digital Probe thermometers – a device that uses sensitive resistors in a
probe to measure temperature, they have quite a high temperature
range too along with everything being electrical. Overall, they are
quicker and more clarifying which makes them the most efficient and
accurate to use when doing experiments.