MadSci Network: General Biology

Subject: Why does iodine pass through a plastic bag?

Date: Sun Jun 14 17:26:09 1998
Posted by Sharon Emery
Grade level: teacher/prof
School: No school entered.
City: Wading River State/Province: NY
Country: USA
Area of science: General Biology
ID: 897863169.Gb

I found an experiment to perform and it works, but I don't understand
why.  Mix cornstarch and water, and place it inside a 
plastic bag, then seal it. Place the sealed bag in a beaker of
water plus 15 drops of iodine.  After 15min or so, the cornstarch
mixture becomes purple, and the water and iodine remain orange/brown.

Why does the iodine permeate the plastic bag?  I know it has to 
do with osmosis, but I don't know what chemical properties iodine
has that it can permeate the plastic.

Thanks for your help.

Re: Why does iodine pass through a plastic bag?

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

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.