Part 1:Producing a cooling curve for water
Aim- To show how the temperature changes as a substance is cooled down
Hypothesis- As time increases, the cooling curve decreases making the relationship between time
and temperature inversely proportional as heat loss will lead to a decrease in temperature with no
change of state.
Introduction- A cooling curve is a line graph that shows how the state of matter changes, often from
a liquid to a solid or from a gas to a solid. The gradient of the cooling curve depends on the materials
thermal conductivity, heat capacity, and external
temperature.The gradient of the curve will be smaller if more heat is needed to raise the substance's
temperature since it will cool more slowly.
A substance cools more quickly the higher its thermal conductivity because heat is transported more
quickly. This reduces the rate at which heat is transferred out of the substance, reducing the rate of
cooling. Cooling curves are typically used as a tool to compare a liquid or as a method to ensure that
the liquid being used is suitable for continued use and will satisfy current requirements.(1)
Equipment-
100ml beaker
Calorimeter
Boiled tap water
Styrofoam cup
Stand and clamp
Stop clock
Thermometer
Calibrating a thermometer
Place the thermometer stem or probe into the ice water.Wait 30 seconds or until the reading stays
steady.Adjust the thermometer so it reads 0°c.(2)
Method-
I firstly filled 100 ml beaker to the mark with freshly boiled tap water. I then
poured this water into the thermometer. I wrote
down the water's temperature and set the stopwatch to work. I then took a temperature reading
every 60seconds for about 10 minutes.After I
wrote the findings on a graph showing the temperature (y-axis) with time (xaxis). I finally created
the bestfitting curve through my plots by drawing tangents to the curve at each location. Using the g
radients of the tangents, I calculated the "rate of cooling" at each position.
Risk assessment-
Boiling water- It has many health hazards which include burning yourself when in direct contact and
spillage which can cause someone to slip and when spilled next to a socket or any electricity, it can
cause you to get electrocuted and severely harm you. To prevent these potential hazards what I did
was make sure all chairs and bags are tucked in so no one would trip and spill the liquid and also
made sure to put on our lab coats and wore gloves to protect our skin and prevent direct contact.
Glassware- This is also another potential hazard as glassware can break. When this occurs, various
outcomes can happen including cutting yourself or someone around you. To prevent this, we
handled the glassware with care and also made sure all bags and chairs were under the table so no
, one would trip and drop the glass. Goggles also came in handy to prevent glass or hot water from
entering.
Results-
Ice water Hot water
Time(min) Temp(°c) Time(min) Temp(°c)
1. 0.1° 1. 87°
2. 0.1° 2. 82°
3. 0.1° 3. 80°
4. 0.1° 4. 79°
5. 0.1° 5. 77°
6. 0.1° 6. 76°
7. 0.1° 7. 76°
8. 0.1° 8. 75°
9. 0.1° 9. 74°
10. 0.1° 10. 72°
Ice cooling curve
TIME(minutes)
Aim- To show how the temperature changes as a substance is cooled down
Hypothesis- As time increases, the cooling curve decreases making the relationship between time
and temperature inversely proportional as heat loss will lead to a decrease in temperature with no
change of state.
Introduction- A cooling curve is a line graph that shows how the state of matter changes, often from
a liquid to a solid or from a gas to a solid. The gradient of the cooling curve depends on the materials
thermal conductivity, heat capacity, and external
temperature.The gradient of the curve will be smaller if more heat is needed to raise the substance's
temperature since it will cool more slowly.
A substance cools more quickly the higher its thermal conductivity because heat is transported more
quickly. This reduces the rate at which heat is transferred out of the substance, reducing the rate of
cooling. Cooling curves are typically used as a tool to compare a liquid or as a method to ensure that
the liquid being used is suitable for continued use and will satisfy current requirements.(1)
Equipment-
100ml beaker
Calorimeter
Boiled tap water
Styrofoam cup
Stand and clamp
Stop clock
Thermometer
Calibrating a thermometer
Place the thermometer stem or probe into the ice water.Wait 30 seconds or until the reading stays
steady.Adjust the thermometer so it reads 0°c.(2)
Method-
I firstly filled 100 ml beaker to the mark with freshly boiled tap water. I then
poured this water into the thermometer. I wrote
down the water's temperature and set the stopwatch to work. I then took a temperature reading
every 60seconds for about 10 minutes.After I
wrote the findings on a graph showing the temperature (y-axis) with time (xaxis). I finally created
the bestfitting curve through my plots by drawing tangents to the curve at each location. Using the g
radients of the tangents, I calculated the "rate of cooling" at each position.
Risk assessment-
Boiling water- It has many health hazards which include burning yourself when in direct contact and
spillage which can cause someone to slip and when spilled next to a socket or any electricity, it can
cause you to get electrocuted and severely harm you. To prevent these potential hazards what I did
was make sure all chairs and bags are tucked in so no one would trip and spill the liquid and also
made sure to put on our lab coats and wore gloves to protect our skin and prevent direct contact.
Glassware- This is also another potential hazard as glassware can break. When this occurs, various
outcomes can happen including cutting yourself or someone around you. To prevent this, we
handled the glassware with care and also made sure all bags and chairs were under the table so no
, one would trip and drop the glass. Goggles also came in handy to prevent glass or hot water from
entering.
Results-
Ice water Hot water
Time(min) Temp(°c) Time(min) Temp(°c)
1. 0.1° 1. 87°
2. 0.1° 2. 82°
3. 0.1° 3. 80°
4. 0.1° 4. 79°
5. 0.1° 5. 77°
6. 0.1° 6. 76°
7. 0.1° 7. 76°
8. 0.1° 8. 75°
9. 0.1° 9. 74°
10. 0.1° 10. 72°
Ice cooling curve
TIME(minutes)
