Unit 2: Assignment 2 - Cooling Curves
ABSTRACT
In this assignment I used the cooling curve to determine the rate of
cooling of substances, obtained data using the equipment provided in
order to construct cooling curves, analysed the rate of cooling of
substances from the recorded data using the cooling curves to draw
conclusions and I also evaluated the accuracy of my practical work in
relation to the analysis of the cooling curves. Moreover, I also
calibrated the thermometers that were provided to me, the alcohol,
mercury and digital thermometers. Calibrating thermometers updates
the indications and thus allowed me to maintain accurate, reliable and
consistent results when taking the temperature measurements.
PART- I
CALIBRATION OF THERMOMETERS
INTRODUCTION
Calibration is the process of ensuring that an instrument that might be
used in an experiment will produce precise readings. Calibration is
vitally important when taking measurements as it enables the users to
have confidence in the results that they monitor, record and
subsequently control.
Over time there is a tendency that an equipment’s accuracy might drift
while measuring parameters such as temperatures. To be sure that the
results being measured are accurate, there is an ongoing need to
maintain the calibration of equipment throughout its lifetime to produce
reliable, accurate and repeatable measurements.
The objective of calibration is to minimise any errors in measurements
by confirming the accuracy of the equipment.
, APPARATUS
1. Thermometers (alcohol, mercury and digital)
2. Crushed ice
3. Water
4. 500 ml Glass beaker
5. Stopwatch
6. Bunsen burner
7. Tripod and gauze
8. Glass rod
9. Heat resistant mat
RISK ASSESSMENT
• Wear a lab coat and goggles when performing the experiment.
• Handle the glassware very carefully. Mishandling glassware could
cause cuts.
• When reading the degree make sure there is no parallax.
• Heat the water in the beaker gently so the temperature doesn’t
rise up very fast.
• Stir to ensure even distribution of heat.
PROCEDURE
Calibrating – Using Ice:
1. I filled an insulated glass beaker with crushed ice.
2. Added 1/2 cup of water from a sink. I allowed the ice mixture to
sit for five minutes.
3. Inserted the sensing end of the thermometers into the centre of
the ice mixture and pushed the thermometers to the middle of the
glass beaker.
4. For the digital thermometer I let it sit in the ice mixture for at
least 30 seconds. The thermometer should display 0 C on its
o
display. If the thermometer read “Error” or another temperature,
I had to repeat steps 3 and 4.
5. I pressed the “Reset” button located on the side of the
thermometer. The digital thermometer was thus calibrated.
6. For the alcohol and mercury thermometers I inserted them in the
beaker with the crushed ice and recorded the readings.
ABSTRACT
In this assignment I used the cooling curve to determine the rate of
cooling of substances, obtained data using the equipment provided in
order to construct cooling curves, analysed the rate of cooling of
substances from the recorded data using the cooling curves to draw
conclusions and I also evaluated the accuracy of my practical work in
relation to the analysis of the cooling curves. Moreover, I also
calibrated the thermometers that were provided to me, the alcohol,
mercury and digital thermometers. Calibrating thermometers updates
the indications and thus allowed me to maintain accurate, reliable and
consistent results when taking the temperature measurements.
PART- I
CALIBRATION OF THERMOMETERS
INTRODUCTION
Calibration is the process of ensuring that an instrument that might be
used in an experiment will produce precise readings. Calibration is
vitally important when taking measurements as it enables the users to
have confidence in the results that they monitor, record and
subsequently control.
Over time there is a tendency that an equipment’s accuracy might drift
while measuring parameters such as temperatures. To be sure that the
results being measured are accurate, there is an ongoing need to
maintain the calibration of equipment throughout its lifetime to produce
reliable, accurate and repeatable measurements.
The objective of calibration is to minimise any errors in measurements
by confirming the accuracy of the equipment.
, APPARATUS
1. Thermometers (alcohol, mercury and digital)
2. Crushed ice
3. Water
4. 500 ml Glass beaker
5. Stopwatch
6. Bunsen burner
7. Tripod and gauze
8. Glass rod
9. Heat resistant mat
RISK ASSESSMENT
• Wear a lab coat and goggles when performing the experiment.
• Handle the glassware very carefully. Mishandling glassware could
cause cuts.
• When reading the degree make sure there is no parallax.
• Heat the water in the beaker gently so the temperature doesn’t
rise up very fast.
• Stir to ensure even distribution of heat.
PROCEDURE
Calibrating – Using Ice:
1. I filled an insulated glass beaker with crushed ice.
2. Added 1/2 cup of water from a sink. I allowed the ice mixture to
sit for five minutes.
3. Inserted the sensing end of the thermometers into the centre of
the ice mixture and pushed the thermometers to the middle of the
glass beaker.
4. For the digital thermometer I let it sit in the ice mixture for at
least 30 seconds. The thermometer should display 0 C on its
o
display. If the thermometer read “Error” or another temperature,
I had to repeat steps 3 and 4.
5. I pressed the “Reset” button located on the side of the
thermometer. The digital thermometer was thus calibrated.
6. For the alcohol and mercury thermometers I inserted them in the
beaker with the crushed ice and recorded the readings.
