Why do you get pruney in water?

Question

I need a very scientific reason of why you prune up in the bath tub.

I need an ultra extremely scientific answer...

Answer 1

Skin cells expand from absorbing water (osmosis).

There is less osmosis in an ISOTONIC solution; i.e. one having similar dissolved salts concentration to blood plasma.

You can put red blood cells in water, watch them burst (hemolysis from absorbing the hypotonic water solution).

In isotonic solution the RBCs would not change size or appearance.

In hypertonic solution (excess of dissolved salts) the RBCs become 'crenated.' They shrink from losing water....

If your skin cells enlarge they have more surface area for covering the same amount of you. The excess surface area causes wrinkling.

A very obsese person who undergoes liposuction also ends up with excess skin in flaps and folds, from skin of former fat surface area now covering a smaller surface area person. But that is not the same as getting wrinkly skin in water.

This question must be #117 after 'Why is the sky blue?'

Answer 2

http://www.kidshealth.org/kid/talk/qa/wrinkly_fingers.html

Answer 3

pressure