Wednesday, November 28, 2012

Gummy Bear Osmosis

I taught my grade 8 science class today about osmosis using gummy bears!!  YUM!!  I got the idea from THIS site.  

The idea is that if you put a gummy bear in water it is going to swell and absorb the water (high concentration of water in the dish to the low concentration of water in the bear).  When you put a gummy bear in salt water now there is a higher relative concentration of water in the gummy bear than in the salt water AND a higher concentration of salt in the water than in the bear.  The salt can not move in to the bear because it's selectively permeable membrane wont let in such big molecules so the water from the bear has to move out to equalize the concentrations   If you look closely you can even see the red colouring leaking into the salt water from the bear.  Very cool.

If that blew your mind just watch this video to explain osmosis again.

**See HERE for how we challenged Canadian Astronaut, Jeremy Hansen, to the gummy bear lab challenge under the sea!  See the results HERE**


AFTER only TWO hours!  - Notice how the ones on the left are larger and the ones on the right (salt) are smaller and the red dye has spread in to the salt solution.



I let them dry overnight.  Look at how the salt soaked ones are SMALLER than the normal ones even when dry!
Look at the results after 24 hours!!  The ones in water are HUGE and even though the ones in the salt water have grown they are not nearly as large and have lost their colour into the solution.  I wonder what they will look like once they dry out?





2 comments:

  1. wow i did this in science too. it was so awesome. :) but i have a question to ask (if you don't mind). Which one has the highest concentration of H2O gummy bears, the salt water, or just the normal water?

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  2. Not sure what you are asking? The plain water gummy bears have more water in them, higher concentration.

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