# The Naked Scientists Forum

### Author Topic: How many bubbles are there in a bar of soap?  (Read 10931 times)

#### science_guy

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##### How many bubbles are there in a bar of soap?
« on: 14/05/2008 03:59:10 »
I was watching the movie "Freedom Song" about the civil rights movement, and at one point in the movie the officials prevented the black people from registering to vote by requiring that they know how many bubbles there are in a bar of soap.

being a pursuer of the irrelevant, is such a thing possible to calculate?

how many bubbles ARE there in a bar of soap?
« Last Edit: 15/05/2008 09:29:25 by chris »

#### rosalind dna

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##### Re: How many bubbles are there in a bar of soap?
« Reply #1 on: 14/05/2008 10:43:07 »
It depends on what the reason is that you want to know about the
amount of bubbles in a bar of soap?

But as far as I know they are there because of trapped air bubbles in the initial making of a bar of soap before it's put on the shelves.

#### neilep

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##### Re: How many bubbles are there in a bar of soap?
« Reply #2 on: 14/05/2008 11:42:04 »
This is really an impossible question to answer though I can imagine if enough consistent tests were done with the same bars of soap you may be able to come to a  " generalistic guestimate "...

.....bubbles are of course different sizes and are produced in different ways dependent on how the bar of soap is used.....But how do you count them ?......bubbles can be tiny !.....I would not be surprised if the numbers were very very high indeed...in the many millions !.......perhaps even that may be an understatement in the extreme.....when you think of foam.....it literally is bubbles in vast quantities.

#### Karen W.

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##### Re: How many bubbles are there in a bar of soap?
« Reply #3 on: 14/05/2008 15:25:48 »
I was watching the movie "Freedom Song" about the civil rights movement, and at one point in the movie the officials prevented the black people from registering to vote by requiring that they know how many bubbles there are in a bar of soap.

being a pursuer of the irrelevant, is such a thing possible to calculate?

how many bubbles ARE there in a bar of soap?

Obviously not possible in my opinion just a way to insure no blacks were voting... just pure prejudice rearing its ugly head as You read!Thats a horrible thing..
I had never heard that one before... amazing the lengths they went to try to justify or continue their prejudices!

Depending on the vigor in which a bar of soap was used, how could one possibly count them so many are made and popped as the friction continues to create and destroy.... It seems impossible to me...also.. I agree with Neil.

#### Bored chemist

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##### Re: How many bubbles are there in a bar of soap?
« Reply #4 on: 14/05/2008 17:51:03 »
Surely the answer is "generally none"? After all, it's a solid block of soap*.
Of course, you can make lots of bubbles with a bar of soap and some water.

* Yes, I know there are floating soaps with bubbles in.

#### science_guy

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##### Re: How many bubbles are there in a bar of soap?
« Reply #5 on: 14/05/2008 19:03:59 »
maybe if you counted a "bubble" as to be about an inch in diamater... count the soap/water ratio of it, and divide the amount of soap into the amount in the bar?

anybody with too much time on their hands?

#### Karen W.

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##### Re: How many bubbles are there in a bar of soap?
« Reply #6 on: 14/05/2008 20:42:43 »
NOT I! LOL.. You are out of my range.. Go for it science guy! Hee hee hee!LOL

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##### Re: How many bubbles are there in a bar of soap?
« Reply #7 on: 15/05/2008 00:56:22 »
Which bar of soap? this one or that one

#### Karen W.

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##### Re: How many bubbles are there in a bar of soap?
« Reply #8 on: 15/05/2008 01:53:42 »
lol lol..good one!

#### science_guy

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##### Re: How many bubbles are there in a bar of soap?
« Reply #9 on: 15/05/2008 03:25:01 »
umm... that one!

#### Soul Surfer

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##### How many bubbles are there in a bar of soap?
« Reply #10 on: 15/05/2008 17:44:14 »
Basically it depends how much energy you are prepared to put into making the bubbles. Bubbles always have air at slightly higer pressure in them than the local atmospheric pressure because of the surface tension of the water film which tends to contract like an elastic band  the more curved the surface the higher the pressure in the bubble so to make small bubbles you need more energy.  You can see this because big bubbles are floppy and small bubbles quite hard.

#### neilep

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##### How many bubbles are there in a bar of soap?
« Reply #11 on: 15/05/2008 19:10:18 »
Despite the sage advice above , I have empirically counted all the bubbles produced by a bar of soap...and the answer is 73.

#### science_guy

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##### How many bubbles are there in a bar of soap?
« Reply #12 on: 15/05/2008 19:19:31 »
thankyou neilep! those must have been very big bubbles indeed!

#### neilep

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##### How many bubbles are there in a bar of soap?
« Reply #13 on: 15/05/2008 19:40:50 »
thankyou neilep! those must have been very big bubbles indeed!

LOL...you're still in my head !!

Well...it was a very very small bar.....about the size of an M&M !!

#### The Naked Scientists Forum

##### How many bubbles are there in a bar of soap?
« Reply #13 on: 15/05/2008 19:40:50 »