# Why do some fuses burn under water? **URL:** \ **Category:** Factual Questions\ **Created:** [December 14, 2002, 11:07pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803 "2002-12-14T23:07:43Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [December 14, 2002, 11:07pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/1 "2002-12-14T23:07:43Z")
Do they get oxygen from the water? Are they not really “burning”? ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [December 14, 2002, 11:15pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/2 "2002-12-14T23:15:58Z")
They are burning, and supply their own oxygen from chemicals:[Plastic Igniter Cord Instantaneous Fuse](http://www.nobel-enterprises.com/jindex.html?ssp_pyro_prod.html) > [@](#): > > Articles contain mixtures of one or more of the following: Red Lead, Potassium Nitrate, Nitrocellulose,Silicon and Potassium Perchlorate, Blackpowder. With the exception of Red Lead and Silicon, all contain potent oxidizers. ---
**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\ **Post date:** [December 14, 2002, 11:16pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/3 "2002-12-14T23:16:36Z")
WAG: they contian an oxidizer, a chemical that releases oxygen as it breaks down. That’s how solid rocket boosters work in a vacuum, anyway. ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [December 15, 2002, 3:24pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/4 "2002-12-15T15:24:51Z")
They also have a water proof coating on them. I have some. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [December 15, 2002, 3:41pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/5 "2002-12-15T15:41:11Z")
For the same reason bombs explode underwater: they contain everything they need for the chemical reaction. ---
**Author:** ![scotth](https://avatars.discourse-cdn.com/v4/letter/s/b9e5f3/32.png) [@scotth](https://boards.straightdope.com/u/scotth)\ **Post date:** [December 15, 2002, 3:44pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/6 "2002-12-15T15:44:29Z")
Expanding on what Fear Itself said: Nitrocellulose is the same thing as smokeless gun powder (more or less). That particular item doesn’t even “oxidize” per say, but simply breaks down when heated, releasing more heat in the process. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [December 15, 2002, 5:17pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/7 "2002-12-15T17:17:49Z")
\>\> That particular item doesn’t even “oxidize” per say You don’t say! ---
**Author:** ![mrcrow](https://avatars.discourse-cdn.com/v4/letter/m/838e76/32.png) [@mrcrow](https://boards.straightdope.com/u/mrcrow)\ **Post date:** [December 15, 2002, 8:14pm UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/8 "2002-12-15T20:14:52Z")
> [@](#): > > \*Originally posted by scotth \* > \*\*Expanding on what Fear Itself said: > Nitrocellulose is the same thing as smokeless gun powder (more or less). > That particular item doesn’t even “oxidize” per say, but simply breaks down when heated, releasing more heat in the process. \*\* its exothermal once reacted by the percussion cap.🆒 :rolleyes: ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [December 16, 2002, 12:50am UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/9 "2002-12-16T00:50:13Z")
Magnesium and Aluminum burn hot enough that they can dissociate water into hydrogen and oxygen gas. Underwater flares normally rely on oxygen provided by the pyrotechnic mixture, but the chemical equilibrium between H[sub]2[/sub]O + Mg \<—\> H[sub]2[/sub] + MgO lies very far to the right. Firefighters learned this, much to their consternation, in the [Chicago Magnesium fire](http://www.fireworld.com/magazine/magnesium.html). ---
**Author:** ![Rhum\_Runner](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@Rhum\_Runner](https://boards.straightdope.com/u/Rhum_Runner)\ **Post date:** [December 16, 2002, 1:54am UTC](https://boards.straightdope.com/t/why-do-some-fuses-burn-under-water/142803/10 "2002-12-16T01:54:53Z")
I am sure you all saw the videos in school of what happens when you put pure sodium or potassium in water. 🙂