h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Does anyone actually know why you need water AND soap to make bubbles? I guess it has something to do with the surface tension... But I thought soap destroys the water's surface tension!? Well, I ain't that good at physics...

It's probably possible to make bubbles using any liquid, although water based is best. As for 'needing soap', it depends on how long you want the bubbles to last. I often get bubbles when pouring coffee or tea, but they don't last long.

Thinking about it, it's more a case of needing water. Bubbles won't form from pure detergent because it's too thick. Adding water thins it down. I don't know about soap destroying surface tension, though. All I know is it cuts through grease and allows you to get the dishes clean.

Why is it that farts smell 10x worse than normal when they have been bubbled through bath water?

It's actually becase the soap isn't the thing that actually does the cleaning... it's still the water. Soap makes water thinner than water and allows it to remove those annoying bits on your plates.. now for the really stuck on bits I recommend using a pressure washer filled with H2SO4 but that's just me... Removes the bits and the plate.

Ford

Hey, stop thief, bring back my bubble and squeak.

I saw a really impressive demonstration of the physics of bubbles a while back. It was by a prof of mathematics at Rice U. in Houston, part of an evening non-credit course. He had a bunch of wire frames in weird shapes and made the bubbles adhere to the shapes. The weirdest was like the lines on a basketball or baseball, sort of a double saddle shape. He got the bubble to fill the things, touching all the wire, then he blew on the soap film and made it "jump" to the "other" possibility. Maybe you had to be there, but it was impressive, trust me. BTW, he gave me the recipe for the liquid, it had soap, water and glycerine.



- Steve K.

You might find the answer to some of these questions in my own Bubble entry http://www.h2g2.com/A302761
And then again, you might not

I beg to differ that it is not the soap that does the cleaning... try cleaning a greasy plate with pure water.
Strangely, I've written an Entry on the subject, How Soap Works http://www.h2g2.com/A283259

This conversation seems silent, most probably since noone has recomended a good book on Soap Bubbles. So, I wold like to recommend a book by Göran Rämme. I first heard him lecture on Soap Bubbles while waiting for a bunch of delayed nobel laureates to give their customary talks in Uppsala. He is a very entertaining and most enthusiastic speaker totally stuck with abusing bubbles. Well, actually, of late I hear he has even started doing foam research! Some instrumentation vital to bubble research, such as the many-barreled bubble-pipe were invented by this dude.

His latest book is called "Soap Bubbles in Art and Education" (Science Culture Technology Publishing , Singapore ,1998, ISBN 981-04-0648-7). An index can be found at
http://www.fki.uu.se/goran.ramme/index.htm.

Soapy water makes bubbles a lot bigger and better than ordinary water by affecting the surface tension. Contrary to popular belief, soap does not destroy suface tension, it just reduces it. So the 'skin' of the water becomes very stretchy, allowing it to be drawn out to cover a volume of air.. With ordinary water, this can happen, but only for very small bubbles (less than about 2mm), any larger than that, and the bubbles snap. It's like the difference between blowing a bubble with bubblegum and blowing a bubble with, say, dough. It's possible with a mouthful of dough, to get small bubbles, but the bubblegum is better as it stretches more before snapping.

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..oOOO..ooO..ooo..O....oOO..OOO..Oo..Ooo..o..oOo..ooOo..ooO..oOoo..???.

..oooo..ooO..OOo..OOO...

..OO oo OOO oo....