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In zero (or micro) gravity there are lots of problems for a birthday cake. Cakes "rise", and flames "burn up", without gravity how could any of this happen?

Will my cake fail to rise? Will my candles burn?

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    $\begingroup$ Candles will burn if you provide air flow. But first, crew commander will use extinguisher on you and strangle you next. $\endgroup$ – Deer Hunter Jul 29 '13 at 10:45
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    $\begingroup$ Also, if you fly on a spacecraft like Apollo, with reduced atmospheric pressure, not only will the cake bloat unaesthetically, once you light the candles, due to increased oxygen content, the candles will burn entirely in matter of seconds and then the cake will catch fire and burn up right to the plate, frosting, pastry and cream, all of it, with a very bright flame... (well, if you try "lite" with fat-free cream, that cream might survive). $\endgroup$ – SF. Jul 29 '13 at 11:02
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    $\begingroup$ Would a spherical instead of cylindrical cake be acceptable? $\endgroup$ – Philipp Jul 30 '13 at 8:26
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    $\begingroup$ @Philipp if you use a mold you can have any gravity defying shape you want :) $\endgroup$ – James Jenkins Jul 31 '13 at 10:26
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    $\begingroup$ @Philipp how would you make (and especially bake) a spherical cake?! :) $\endgroup$ – Zoltán Schmidt Aug 13 '13 at 11:03
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The cake will "rise" for the same reasons it does in gravity (yeast or other agents releasing gases as a metabolic byproduct, when heated, or as a chemical process and reacting to other ingredients, given sufficient time and providing for other required conditions to activate the rising agent). The only problem is, it will "rise" equally in all directions in a zero gravity environment, so you might want to start shaping your dough well before it starts increasing in volume due to internal pressure upon release of gases, maybe even contain this process completely within a cake shaped container that you bake the dough in (there's no real names for such "kitchen tools" yet for those that will be required in zero gravity, so I'm just using some generic terms - I'm sure Gordon Ramsay would have something to yell about regarding my choice).

And the candles will burn without the flame "rising" in a single direction, but again - equally in all directions, so the "flame" will be more or less spherical, with only the candle wick slightly misshaping it towards a cylinder shape (assuming it will distribute wax due to suction - a byproduct of burning and expanding in volume - equally along its length). So the flame would look like a product of a sphere and a cylinder (slightly flattened "top"), but nearly completely flattened where the candle wax is still solid ("bottom") due to candlestick's surface tension, melting of wax, and suction of air from all directions equally - but the candlestick is slightly in the way and this air pressure slightly increases there as the path narrows). This experiment has been performed on Mir and the video is available on YouTube, and the shape the flame forms confirms all the physical processes described, albeit the experiment seems to have been conducted in a smaller to sea-level Earth's atmospheric pressure, or in atmosphere with slightly smaller percentage of oxygen (the colour of the flame suggests the former to be more probable cause of it).

                     Candle flame in Zero-G on the Mir

                     Candle flame in Zero-G on the Mir

Yes, you could have a cake in zero-g, and you could eat it, but then you wouldn't have it any more. :)

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