MadSci Network: General Biology

Re: Why does iodine pass through a plastic bag?

Date: Wed Jun 24 10:49:50 1998
Posted By: David Beck, MadSci Admin
Area of science: General Biology
ID: 897863169.Gb

This works because plastic has pores in it and thus the plastic bag acts 
as a semi-permeable membrane. The cornstarch particles are too large to 
pass through the pores in the plastic, they are large polymers of glucose. 
The iodine passes easily because it is a atom, and thus much smaller than the 
starch. Water molecules are too large too pass through the pores, and thus the
only thing that can move across the membrane are the iodine ions.  The iodine
ions move about randomly, and in the course of this, some of them pass through
the pores. 
Shannon Beck

Current Queue | Current Queue for General Biology | General Biology archives

Try the links in the MadSci Library for more information on General Biology.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-1998. All rights reserved.