# heating water with mechanical energy **URL:** \ **Category:** Factual Questions\ **Created:** [May 4, 2006, 12:46pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376 "2006-05-04T12:46:03Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [May 4, 2006, 12:46pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/1 "2006-05-04T12:46:03Z")
We are given the task of heating a beaker of water using only mechanical energy. What are some ways that this could be done using simple materials? The mechanical energy can be converted to any other form of energy. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [May 4, 2006, 12:51pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/2 "2006-05-04T12:51:11Z")
Use a generator to power a heating element. ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [May 4, 2006, 1:12pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/3 "2006-05-04T13:12:57Z")
You could cool the water by the chilly reception you’ll get by asking people to do your homework on a message board dedicated to fighting ignorance. 😃 ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [May 4, 2006, 1:28pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/4 "2006-05-04T13:28:35Z")
If you take a pool pump (or almost any pump), and connect the inlet right to the output via a short hose and somehow get water into this ‘loop’. Run the pump for a bit and the water will heat up. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [May 4, 2006, 1:30pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/5 "2006-05-04T13:30:11Z")
How hot do you want the water to get? Stirring it, or pouring it onto the floor would get you _some_ heat. For higher temps, consider an underwater variation on the [Bow Drill](http://video.google.com/videoplay?docid=6648971288621833015&q=bowdrill&pl=true). ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [May 4, 2006, 1:39pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/6 "2006-05-04T13:39:58Z")
Rub two sticks together to make a fire. 😃 ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [May 4, 2006, 1:40pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/7 "2006-05-04T13:40:19Z")
My Vita-Mix will boil water in about 5 minutes from the friction of the blades. Is a Vita-Mix a “simple material”? Prob’ly not. ---
**Author:** ![glee](https://avatars.discourse-cdn.com/v4/letter/g/b5a626/32.png) [@glee](https://boards.straightdope.com/u/glee)\ **Post date:** [May 4, 2006, 2:06pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/8 "2006-05-04T14:06:10Z")
> [@solkoe](#): > > We are given the task of heating a beaker of water using only mechanical energy. What are some ways that this could be done using simple materials? > The mechanical energy can be converted to any other form of energy. How about converting the mechanical energy to heat? Or doing your own homework?! 😛 ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [May 4, 2006, 3:17pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/9 "2006-05-04T15:17:47Z")
You could also use a generator hooked up to a hot plate. Turning shaft is mechanical energy, which you convert to electrical energy to heat. ---
**Author:** ![casdave](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@casdave](https://boards.straightdope.com/u/casdave)\ **Post date:** [May 4, 2006, 4:16pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/10 "2006-05-04T16:16:34Z")
Think friction. ---
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [May 4, 2006, 4:39pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/11 "2006-05-04T16:39:40Z")
> [@NurseCarmen](#): > > You could cool the water by the chilly reception you’ll get by asking people to do your homework on a message board dedicated to fighting ignorance. > > 😃 NurseCarmen, I am 42 years old and this is hardly my homework. Never assume. ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [May 4, 2006, 4:48pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/12 "2006-05-04T16:48:48Z")
Why did you start the post “We are given the task?” I know you are new to the boards, so let me explain my reply. Quite often, kids come in and ask questions that have clearly come from school assignments. Some have even had the balls to put multiple questions in a single thread. Yours certainly looked the part. A question, no input, no ideas of your own. ---
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [May 4, 2006, 4:56pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/13 "2006-05-04T16:56:52Z")
> [@Rick](#): > > Rub two sticks together to make a fire. 😃 We thought of this but rejected the idea because even though the rubbing is mechanical, the energy from the burning fuel is chemical. In the same way, the idea of lighting a match is not a valid solution because only a fraction of the energy produced is mechanical. ---
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [May 4, 2006, 5:44pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/14 "2006-05-04T17:44:55Z")
> [@NurseCarmen](#): > > Why did you start the post “We are given the task?” > > I know you are new to the boards, so let me explain my reply. Quite often, kids come in and ask questions that have clearly come from school assignments. Some have even had the balls to put multiple questions in a single thread. Yours certainly looked the part. A question, no input, no ideas of your own. I understand your concern. It would be great to be able to get all the materials together and test my predictions experimentally. Unforturnately, I am more of a thinker than a doer. I did think of friction and heat from a generator. I was wondering if I was missing something obvious. I love this board because it is a fast way for me to pick the brains of many many people. For my part, I would be impressed if any of my students had the ambition to even ask for _my_ advice on a topic such as this let alone go online to look for an answer. I may be a new member but I have been reading the message board for over a year. I am familiar with how it works. All kinds of questions get asked. I love the message board because I can learn from so many people. In the future, I will phrase my questions in such a way as to not look like a student. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 4, 2006, 7:31pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/15 "2006-05-04T19:31:52Z")
Get two steel plates. Place the water on one and spin the other underneath and touching the first plate (obviously the top plate would need to be anchored from moving). The friction will heat things nicely (think of the brakes on your car). You can spin the plate with any number of methods but getting things hot enough to boil water wouldn’t be too hard and the whole setup can be purely mechanical. (Note maybe two “steel” plates are not the best material choices but whatever would be ideal the premise is the same) ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 4, 2006, 7:36pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/16 "2006-05-04T19:36:58Z")
Here is a simpler version of what I was talking about. 100% mechanical (human powered by hand). > [@](#): > > **Tyndall’s Water-Boiling Apparatus** > This is a Mechanical Equivalent of Heat demonstration. A [missing] belt connects the two pulleys, and allows the smaller pulley to be driven at a high rotation rate as the hand-crank is turned. Projecting upward from the smaller pulley is a thin-walled brass pipe, partly filled with water and closed with a cork. Two pieces of oak, hinged together, surround the pipe and are held in place by the hand of the demonstrator. The work done in turning the crank against the frictional torque serves to heat the water to boiling, whereupon the cork pops out. > > SOURCE: [http://physics.kenyon.edu/EarlyApparatus/Thermodynamics/Tyndalls\_Water-Boiling\_Apparatus/Tyndalls\_Water-Boiling\_Apparatus.html](http://physics.kenyon.edu/EarlyApparatus/Thermodynamics/Tyndalls_Water-Boiling_Apparatus/Tyndalls_Water-Boiling_Apparatus.html) ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [May 4, 2006, 9:52pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/17 "2006-05-04T21:52:31Z")
> [@kanicbird](#): > > If you take a pool pump (or almost any pump), and connect the inlet right to the output via a short hose and somehow get water into this ‘loop’. Run the pump for a bit and the water will heat up. Better yet, use a centrifugal pump and dead head it. If ‘mechanical energy’ isn’t limited to kinetic energy (and I don’t think it is), then I’d just set the beaker of water out in the sun. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [May 4, 2006, 9:56pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/18 "2006-05-04T21:56:27Z")
Setting the beaker in the sun? The water isn’t being heated by mechanical energy, but by radiation. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [May 4, 2006, 10:02pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/19 "2006-05-04T22:02:38Z")
> [@Lemur866](#): > > Setting the beaker in the sun? The water isn’t being heated by mechanical energy, but by radiation. You picking the beaker up and carrying it outside is certainly a contributing factor. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 4, 2006, 10:22pm UTC](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376/20 "2006-05-04T22:22:52Z")
The real question is, how could you _not_ heat up the water? The thing about heat is, it’s really easy to convert any form of energy to heat (far easier than the reverse). Any way you could possibly introduce mechanical energy to the system, you’re almost guaranteed to convert almost all of it to heat. [Next page](https://boards.straightdope.com/t/heating-water-with-mechanical-energy/355376.md?page=2)