Introduction:

The rate at which an object cools (i.e. how quickly its temperature decreases) depends upon several factors, including:

  • Surface area
  • Volume
  • Type of insulation
  • Temperature difference with the surroundings

For this investigation, the effect of the temperature of water upon the rate of cooling will be investigated. The temperature-drop over 5 minutes (600 seconds) will be measured for 200ml of water at different start temperatures. The average rate of cooling can then be found by:

avg-rate-of-cooling

Apparatus:cooling

  • digital stopwatch
  • 250ml beaker
  • rubber bung
  • thermometer
  • bunsen burner
  • tripod
  • gauze
  • retort stand and clamp
  • goggles

Control Variables:

  • Volume of water used: 150ml
  • Size of beaker (i.e. constant surface area): 250ml
  • Time interval of cooling: 5.0 minutes (600 seconds)
  • Temperature of the room: 21°C

Method:

  • Fill an empty beaker with exactly 150ml of water (check side-scale of beaker)
  • Set up apparatus as shown above. Ensure the thermometer is about 2cm above the bottom of the beaker.
  • Light the bunsen burner and put on a blue flame. Heat up the water.
  • When the temperature on the thermometer has reached 90°C, immediately switch off the burner.
  • Start the stopwatch and time for 5.0 minutes.
  • Read the thermometer value at the 5.0 minute mark.
  • Before repeating the experiment, check the level of water is still 150ml (some may have evaporated) and add more water if required.
  • For different start temperatures, repeat steps 3-7 but turn off the burner at the desired temperature.

Results:

Start Temperature of Water (°C)Temperature after 5min (°C)Drop in Temperature

(°C)

Average Rate of Cooling x 1000 (°C/s)
80701017
7566915
7062813
6559610
605558

 

cooling-rate-graph

Conclusion:

There is a strong correlation between the average rate of cooling and the start temperature: the greater the start temperature, the faster the average rate of cooling.

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fawziya A.PriJorgestudentAngie Recent comment authors
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guest
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guest

risk assessment?

student
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student

5 mins is not 600 seconds

Angie
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Angie

How 5 minutes can be 600 sec ? I think it is 300 sec therefore the average rate of cooling is wrong.

brian
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brian

WOWWW!! best link ever.

Georgia
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Georgia

This is the best link EVER!!!!!!!!!

guest
Guest
guest

this was a real nice bit of work gotta love it

jack
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jack

helpful ._.

Alisha M.
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Alisha M.

this is very helpful thanks!

Guest
Guest
Guest

hi, nice work! Useful for the CAU

Nikesh C.
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Nikesh C.

thanks! this was very helpful.

Henry P.
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Henry P.

Perfect, thanks

callum E
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callum E

amazing wow its so good I cant believe it

S.Henry
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S.Henry

thanks

Alex
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Alex

i need another source like this to compare, but i can’t find any. help with link?

Nigel M.
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Nigel M.

Wow this has helped me so great thank !

Georgia M.
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Georgia M.

Risk assessment?

M. Gurung
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M. Gurung

This was very helpful.

guest
Guest
guest

lovely stuff

Johnny B.
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Johnny B.

you’re very helpful!

Tim B.
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Tim B.

thanks. A++ now

Billy
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Billy

I need help with this.

Jorge
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Jorge

Awesome