Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: lancenti on 11/10/2009 17:03:07

Title: What determines how many bubbles form in a liquid?
Post by: lancenti on 11/10/2009 17:03:07

It's been a while since I last posted, but I hope you guys can help me out!

Does anyone have any idea on how heat or concentration or how vigorous whisking might affect the formation of bubbles in a liquid? I'm trying to make the MOST bubbles with as small a size as possible - i.e. I just want foam.

So far, I've established that very hot water prevents the small foam from forming - in fact I get really few big bubbles and almost no small bubbles this way.


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Title: What determines how many bubbles form in a liquid?
Post by: Madidus_Scientia on 18/10/2009 17:23:02

At my workplace we have tanks of heated chemicals which have foamers on the surface, the foam acts as insulation to conserve heat. We have found that foam with smaller bubbles is the most effective. Our foamers work by just pumping a jet of the liquid (which has a surfactant in it to help make the bubbles) through nozzles down into the surface, we have found that the best way to achieve smaller bubbles is to have the end of the nozzle close down to the surface but not actually in the liquid.

I would also be interested if anyone has other ideas for a better way to make foam.

Title: What determines how many bubbles form in a liquid?
Post by: RD on 18/10/2009 17:40:33

Quote from: Madidus_Scientia on 18/10/2009 17:23:02

I would also be interested if anyone has other ideas for a better way to make foam ?.

What about using the same recipe as fire fighting foam (http://en.wikipedia.org/wiki/Fire_fighting_foam),

or closely inspect many pints of Guinness  ... http://news.softpedia.com/news/Mathematics-And-the-Best-Beer-53143.shtml

Quote

smaller bubbles need a higher internal pressure to balance the greater surface tension,
 which is inversely proportional to the radius of the bubbles.

http://en.wikipedia.org/wiki/Widget_%28beer%29

Title: What determines how many bubbles form in a liquid?
Post by: Madidus_Scientia on 18/10/2009 18:28:33

Well, we don't want too much foam, or the tank will overflow;

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fimg200.imageshack.us%2Fimg200%2F6960%2Fwhoopsk.jpg&hash=a8d4672e0a26a2b9b7924c14ba555eba)

That's what happens if your bubbles are too big!

Title: What determines how many bubbles form in a liquid?
Post by: RD on 19/10/2009 03:15:15

Last time I saw something like that Steve McQueen was fighting it ...

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