Temperature of Hot Water and Cooling Rate Lab

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:

Apparatus:

• 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 the 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:

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.

William Anderson (Schoolworkhelper Editorial Team)

William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0

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