Is it possible to boil water by stirring it?

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Discussion Overview

The discussion revolves around the question of whether it is possible to boil water by stirring it, exploring theoretical and practical aspects, energy requirements, and implications for various setups. Participants consider both the physics behind the process and real-world applications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • Some participants suggest that theoretically, work done on a liquid can increase its temperature, referencing the Joule experiment.
  • Others argue that practical limitations, such as heat loss to the environment, would prevent boiling without specific conditions.
  • A few participants mention cavitation as a practical method to achieve boiling through stirring.
  • Some contributions highlight that the starting temperature of the water and atmospheric pressure are significant factors in determining the feasibility of boiling through stirring.
  • One participant describes a scenario in centrifugal pumps where water can boil due to insufficient heat dissipation, suggesting a practical example of the phenomenon.
  • Another participant emphasizes the substantial energy required to boil water, noting the latent heat of vaporization and comparing it to other methods of generating steam.
  • Real-world examples are provided, including industrial processes and nuclear reactor operations, where stirring or pumping can lead to heating effects.
  • Some participants share personal experiences and calculations related to the energy input required for stirring water to boiling temperatures.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement regarding the feasibility of boiling water by stirring. While some acknowledge theoretical possibilities, others emphasize practical challenges, leading to multiple competing views on the topic.

Contextual Notes

Participants note limitations related to assumptions about energy loss, the efficiency of stirring mechanisms, and the specific conditions under which boiling might occur. The discussion remains open-ended with various factors influencing the outcome.

Who May Find This Useful

This discussion may be of interest to individuals exploring thermodynamics, fluid dynamics, engineering applications, and those curious about practical experiments related to heating liquids.

  • #31
russ_watters said:
7 minutes? You know you're supposed to keep the door closed, right?
I did the experiment on my microwave yesterday and found that it's output is about 400 watts. It's nameplate output is 650 watts. So I googled and found that several sources said that microwave ovens should be replaced every 7 to 10 years due to degradation of the magnetron. I had never heard such a thing.

My microwave is 46 years old, which means it's losing about 5½ watts per year. If it continues at the same rate it with be 2036 when it reaches half of its rated value. Perhaps I'll take some load off it by heating my water in my blender, as it's only 34 years old.
 
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  • #32
I must confess I've never owned a microwave or a blender.
 
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  • #33
PeroK said:
I must confess I've never owned a microwave or a blender.
You spend a lot of time at the neighbor's house apparently... :smile:
 
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  • #34
OmCheeto said:
My microwave is 46 years old, which means it's losing about 5½ watts per year. If it continues at the same rate it with be 2036 when it reaches half of its rated value. Perhaps I'll take some load off it by heating my water in my blender, as it's only 34 years old.

Wow! 46 years.

I think our current microwave is about 15 years old. It works okay but the controller board is going. We can see oddities in its behavior increasing. I wonder if there's some not-too-complicated way to run it without the controller board?
 
  • #35
JT Smith said:
I wonder if there's some not-too-complicated way to run it without the controller board?
I used a power meter ...

... until its LED control gave up.
 
  • #36
Weird.

I connected my Kill-a-Watt meter to my blender and microwave and found their efficiencies in heating water:

Microwave oven: 29%
Blender: 25%

Unfortunately for my blender, it draws a mere 330 watts whilst my microwave draws 1300 watts.
 
  • #37
OmCheeto said:
My microwave is 46 years old,
Perhaps the seal needs checking.
 
  • #38
OmCheeto said:
My microwave is 46 years old, which means it's losing about 5½ watts per year. If it continues at the same rate it with be 2036 when it reaches half of its rated value. Perhaps I'll take some load off it by heating my water in my blender, as it's only 34 years old.
Wait a bit longer and you'll have a refrigerator can generate electricity as a byproduct.
 
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