Wednesday, October 1, 2008

osmosis biology lab

So while I'm pointing out useless scores and numbers, and factoids and senseless drivel, I thought I'd share with ya'll the biology lab I started this evening.  I feel so-very-college-student saying that sentence.  ;)


What we're looking at here is four glasses, each containing 2 pieces of potatoes cut into 10mm x 10mm x 40 mm (or as close as I could get...precision counts here, so the exact measurements and their volume have been documented).



  The fluids are different solutions of salt water, from 0% up to 7%.



The potatoes will sit in their lovely saltwater bath overnight.  And possibly all morning depending on how busy I get tomorrow.  I have three daycare kids (and as you may recall, 3 chitlens of my own) so it's gonna be a swingin' happenin' place tomorrow.  Such is life being me.



This evening I hypothesized (really, I did, it was part of the lab) regarding what would happen to each spud-remain in size, increase in size, decrease in size, etc.  In the morning (or whenever I get around to it) I'll take said taters out of the salt water solutions and measure their volume again.  I'll document and chart and graph and do a lab write up that will take me no less than 3 hours I am sure.



My thoughts are, the 0% solution potatoes will swell, as I think potatoes are already starchy enough that the water in comparison is hypotonic, meaning the water will diffuse back into the potato.  I think the 1.75% solution potatoes will remain the same.  The 3.5% and 7% potatoes will shrink though, because their environment is now hypertonic, and the water will diffuse out of the potatoes causing their cells to wither and wilt and dehydrate a bit.  Such are my hypotheses.

I feel nerdier already.



But suck on that, Trebek.


Christine #2 said...

I so remember this lab. I hated the lab with liver, yuck-o. I always had trouble with the measurements. It's actually harder to cut a rectangle than I thought.

Lorie said...

yeah on your A!!

And how fun to have a science experiment in your kitchen!! And not one accidentally growing in the fridge!!

heather said...

i am so proud of you. I totally dropped out of biology in college. I seriously could not even make it through one whole class it was so horribly boring.