Re: How are soap bubbles similar to human cells?

Firstly the most obvious, both are three dimensional many people think of 
cells as flat. A scanning electron micrograph of a cell clearly shows them 
as nearly spherical. However while a bubble is perfectly spherical a cell 
may have some rigidity and alternative shape, especially when amongst 
other cells in tissues and organs of the body. A single cell in a solution 
would be almost spherical. 

More technically if one leaves aside the contents of a cell, an empty 
cell, the similarities are quite significant. A bubble is made of soap, a 
detergent. A cells membrane is made of fat, or lipids. Both detergents and 
lipids have an extremely similar chemical structure and behave in an 
almost identical way. They are described as “polar”. They both have a 
polar head that which is hydrophilic (water loving) and non-polar tail 
that is hydrophobic (water hating). The tails (repelling against any 
water) will all point into the center providing a protective ring of polar 
heads that happily interact with the surrounding water in any solution – 
this is called a lipid or detergent “micelle”. In a similar way, 
detergents in water form microscopic bubbles or micelles. 

If you increase the size of your micelle (detergent or lipid) it will form 
a bilayer with an inside and outside ring of polar bodies with their tails 
pointing together and their heads to the outside and inside. This is the 
basis of a cell membrane and also a bubble. In a cell the inside is filled 
with cellular organelles and cytoplasm, in a bubble the inside is filled 
with air.

Any cell textbook should have a picture of a lipid micelle and lipid 
bilayer.