[neilep (OP)]

Wifey loves Marshmallows.

I can comfortably predict with a high degree of certainty what will happen when a marshmallow is placed inside her gob !!

..but..in a vacuum ?...is it going to expand with the lack of pressure or is the evacuation of gas  (including what's in the marshmallow) going to make it shrivel it into a marshmallow M & M ?

I don't know...do you ?



Men are the same as women, just inside out !

[daveshorts]

Basically a marsh mallow is a foam. If you drop the pressure the gas inside will expand and some will leak out. I don't think there is a lot to make the marshmallow collapse agian until you add the air back in...

A nice demo
http://phun.physics.virginia.edu/demos/marshmallow.html

Hmmm I am thinking kitchen(ish) science...

[neilep (OP)]

Thank you Dave,

You can see why it can be initially believed to be expected to shrink as the air is drawn out..akin to squeezing it.

Yes, Kitchen science..YAYYY !!..could you use one of those plastic bag vacuum/sealer things ?..or would you need a stronger force like a vacuum cleaner ?..perhaps one of those small hand held jobbies !

Men are the same as women, just inside out !

[eric l]

Your marshmallow could shrink back because of the elasticity of the film.  If there is no pressure left inside, the elastic film will shrink back to the initial volume, very much like when you let the air or gas bleed out of a balloon.  You don't have any vaccuum equipent around to test, do you ?

[neilep (OP)]

Thank you Eric.

I wish I did have a bell jar or something but alas no.

Could something be constructed using a jam jar and a valve ?...or would the jam jar be too fragile ?...probably something made by Pyrex perhaps ?



Men are the same as women, just inside out !

[eric l]

I would not trust a jam jar from a jam I bought in the supermarket.  But you may know the "Weck-jars" our mothers or grandmothers used for home-made preserves. These are made from thick glass, and have a glass cover and flat rubber ring as a joint between them.  Preservation is done by sterilization :  with a kind of spring fixing the lid on top of the jar, the whole is put in a bassin with water, xhich is heated to boiling temperature.  The pressure resulting from heating will find its way out along the flat rubber ring, and on cooling air pressure (or hydrostatic pressure in the bassin) will force the lid more thighly upon the jar, resulting in a partial vaccuum inside the jar.
Of course we will have temperature effects on the marshmellow to deal with, and the relative vaccuum obtained this way will not exceed 1/4 of the atmospheric pressure.  We should try to find some physics class with the right equipment, or some science museum.

[ROBERT]

quote:Originally posted by neilep


I wish I did have a bell jar or something but alas no.

What about a "marital aid" type vacuum pump [][:I]

[neilep (OP)]

quote:Originally posted by ROBERT

quote:Originally posted by ROBERT

quote:Originally posted by neilep


I wish I did have a bell jar or something but alas no.

What about a "marital aid" type vacuum pump [][:I]

It's worn out ![:I][][:I]

Men are the same as women, just inside out !

[Karen W.]

How about my vacuumn sealer, I would love to try this here and send you some lovely science photos of the experiment, tell me what you would like me to do, the steps you would like me to use. I already have the bags, the Sealer and the marshmellows is the rest self explainitory or have I missed something!!!!

Karen

[ROBERT]

quote:Originally posted by Karen W.

How about my vacuumn sealer, I would love to try this here and send you some lovely science photos of the experiment, tell me what you would like me to do, the steps you would like me to use. I already have the bags, the Sealer and the marshmellows is the rest self explainitory or have I missed something!!!!

Karen

For this demonstration the container around the marshmallows must be rigid, not a floppy bag.

[Karen W.]

I think I have a vacumn sealable jar that come with my vacuumn sealer, the tube is inserted into the top of lid and then voila! What do you think?

Karen

[Mjhavok]

Not really a fan of marshmallows myself, they taste to artificial :-S.

I like throwing them at people though. lol. j/k

What the hell. I tried to press "/" and the keyboard got confused. It was doing the action of CTRL + F (which opens the find box). Weird.

Steven

[ROBERT]

quote:Originally posted by Karen W.

I think I have a vacumn sealable jar that come with my vacuumn sealer, the tube is inserted into the top of lid and then voila! What do you think?

Karen

If the jar is designed to be used with the vacuum pump then it should not implode. I doubt that the degree of vacuum would be as high as with "proper" laboratory vacuum equipment, but the marsh mallows should still expand a little with your kitchen apparatus.

[eric l]

Karen's sealable jar will do a better job than the Weck jars I suggested.
Anyway, I think I can safely disclose some testing I have done more than 15 years ago, and not with marshmellows but with other foamy structures.
We were working on plastisols (which are, roughly, solutions of PVC in plasticizer), and because the mixing equipment we had at hand was not really adequate for this applications, our mixes were too foamy by far.  So we made a lid for the mixer bucket, and connected it to a vaccuum pump.
Things got tricky :  if we pumped the air out to quickly, the volume increase of the foam would be so radical that some foam would even get into the safety lock before the pump.
But the safety lock had a bleeding valve, so we could regulate the flow, to a degree that for example only 10 % from the air flow came from the sealed bucket, and 90 % from the free atmosphere.
Well, there was a level where we actually had the foam collapsing, but that would take hours.
Anyway, the project was dropped after 3 or 4 months :  our additive could give the extra strenght we promissed, but showed some disadvantages (of which the price was not the least important).
If I transfer this bit of experience to your marshmallows, the behaviour will depend on the speed by which the air pressure around it is lowered.  And I admit there is some speculation in thinking that a marshmallow will behave exactly like a plastisol.

[Karen W.]

I will try it this weekend!

Karen

[another_someone]

quote:Originally posted by Mjhavok
What the hell. I tried to press "/" and the keyboard got confused. It was doing the action of CTRL + F (which opens the find box). Weird.

You haven't got some application that originated from a UNIX environment?

vi and some other UNIX editors use "/" for find.

George

[daveshorts]

quote:vi and some other UNIX editors use "/" for find.

So does Firefox - at least in linux anyway, much more convenient that having to press two keys... but I am probably biased.

[ariel]

wow, i recall doing this experiment in school and it was soooo long ago that i cant remember what happened hahahaha.
so i googled it and found a picture... looks like it expands

heres a random pic i found...


ariel

[Mjhavok]

quote:Originally posted by another_someone

quote:Originally posted by Mjhavok
What the hell. I tried to press "/" and the keyboard got confused. It was doing the action of CTRL + F (which opens the find box). Weird.

You haven't got some application that originated from a UNIX environment?

vi and some other UNIX editors use "/" for find.

George

No I haven't. It was in firefox. I closed and restarted it and it worked fine again. Weird.

Steven

[neilep (OP)]

So to enjoy BIG marsh-mellows I should put wifey in a vacuum chamber and feed them to her there......She will benefit from massive-marshmellow-madness-goodness !!





Also....on a side note  WHY are they called Marshmellows ?

Men are the same as women, just inside out !