Regents Review Materials – Living Environment

Hello Students, I’m posting some videos and diagrams to help you review for the upcoming Regents Exam.

Here is a video of osmosis in a slice of red onions.   Notice how the size of the red/purple pigment changes when we add the salt solution (the purple will shrink, as the salt sucks the water out of the cells).  The fresh water diffuses out of the cell to balance out the amount inside and outside.  Because it is only water moving (instead of something else, like soda, perfume, or even temperature) we talk about OSMOSIS.



Here is another video about diffusion.  In this one, you can see both the water diffusing out of the cell when we add the salt solution, as well as the water diffusing back thorough the cell membrane into the cell when we add fresh water.  In both cases, the we are seeing water trying to balance out in equal proportions inside and outside the cell.

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