# Motors running on water **URL:** \ **Category:** Factual Questions\ **Created:** [June 26, 2006, 3:53pm UTC](https://boards.straightdope.com/t/motors-running-on-water/362214 "2006-06-26T15:53:54Z")\ **Posts on this page:** 9\ **Page:** 3
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [June 28, 2006, 10:01am UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/41 "2006-06-28T10:01:54Z")
[QUOTE=Malacandra] No, it isn’t; it’s amorphous carbon plus some impurities, the result of incomplete combustion in the fireplace. You could indeed burn it in pure oxygen, of course. [/QUOTE] OK, but a lot of other things we consider ‘burnt’ are also the results of incomplete combustion - like water; the result of incomplete combustion of hydrogen in the presence of oxygen, but absence of fluorine. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [June 28, 2006, 11:05am UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/42 "2006-06-28T11:05:30Z")
[QUOTE=Chronos] Not a very good test. Elemental oxygen is also freakin’ everywhere, and it is, in fact, very reactive. It’s just being replenished as fast as it’s being reacted away. [/QUOTE] I know your point, but the kicksave on my point is that I DID say that it wasn’t reacting, which the oxygen is. There’s also got to be like multiple magnitudes of order more water than there is elemental oxygen on earth. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [June 28, 2006, 11:15am UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/43 "2006-06-28T11:15:49Z")
[QUOTE=Cardinal] I know your point, but the kicksave on my point is that I DID say that it wasn’t reacting, which the oxygen is. There’s also got to be like multiple magnitudes of order more water than there is elemental oxygen on earth. [/QUOTE] I think the distinction would be lost on most casual observers, for a few of reasons: – water _does_ react with things - for example, in causing metals to rust. – even when water isn’t actually reacting, it often _looks like it is_, because it is such a common solvent – oxygen is pretty much invisible, so it’s hard to see it reacting. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [June 28, 2006, 2:32pm UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/44 "2006-06-28T14:32:23Z")
[QUOTE=Mangetout] I think the distinction would be lost on most casual observers, for a few of reasons: – water _does_ react with things - for example, in causing metals to rust. – even when water isn’t actually reacting, it often _looks like it is_, because it is such a common solvent – oxygen is pretty much invisible, so it’s hard to see it reacting. [/QUOTE] A.Water is not changing chemically to make rust. The acidic or salty water acts as a medium for the reaction, and more water is produced by the oxidation of the iron atoms. [http://antoine.frostburg.edu/chem/senese/101/redox/faq/how-iron-rusts.shtml](http://antoine.frostburg.edu/chem/senese/101/redox/faq/how-iron-rusts.shtml) B. Most people don’t think that water is chemically changed when it acts as a solvent. C. Yes, it’s hard to see the oxygen reacting, but by this point in the class I’ve hopefully beat into them that “burning” means “combining with oxygen”, and they’ve already taken biology, so they know that elemental oxygen is involved in some very prevalent reactions. ---
**Author:** ![diggleblop](https://avatars.discourse-cdn.com/v4/letter/d/ac91a4/32.png) [@diggleblop](https://boards.straightdope.com/u/diggleblop)\ **Post date:** [June 28, 2006, 2:35pm UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/45 "2006-06-28T14:35:53Z")
I heard it takes a lot of energy to remove the H from H2O ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [June 28, 2006, 3:15pm UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/46 "2006-06-28T15:15:43Z")
[QUOTE=Cardinal] A.Water is not changing chemically to make rust. The acidic or salty water acts as a medium for the reaction, and more water is produced by the oxidation of the iron atoms. [http://antoine.frostburg.edu/chem/senese/101/redox/faq/how-iron-rusts.shtml](http://antoine.frostburg.edu/chem/senese/101/redox/faq/how-iron-rusts.shtml) [/QUOTE] Rust doesn’t consist solely of metal oxides: > [@](#): > > From [This Wikipedia article on ‘rust’](http://en.wikipedia.org/wiki/Rust) > Rust is the substance formed when iron compounds corrode in the presence of oxygen and water. It is a mixture of iron oxides and hydroxides. Rusting is a common term for corrosion, and usually corrosion of steel. (Graping mine for emphasis) ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [June 28, 2006, 5:28pm UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/47 "2006-06-28T17:28:26Z")
Having reread my link, I see that the hydroxides do come from the water. So basically (ha!) water is consumed to make rust. But I don’t get your point about metal oxides… OHHH. The iron is oxidized when it loses electrons, which is what I was referring to. The atom has been ionized by oxidation. In chemistry nerd-land, what the iron is combined with in the end is kind of immaterial to the term “oxidation”. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [June 28, 2006, 5:36pm UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/48 "2006-06-28T17:36:19Z")
Steve Martin is a trustee of the Los Angeles County Museum of Art. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [June 28, 2006, 5:38pm UTC](https://boards.straightdope.com/t/motors-running-on-water/362214/49 "2006-06-28T17:38:55Z")
Wow, what a screwup. :smack: :rolleyes: 😕 :o [Previous page](https://boards.straightdope.com/t/motors-running-on-water/362214.md?page=2)