Osmosis in potatoes and showing you Kidney Dyalisis

Last tuesday (Before break) we wrapped up osmsosis with a demonstration involving pieces of potato placed into different solution.

I weighed three different pieces of potato and placed them into different solutions.
The first was placed into pure water.  The second was placed into a 10% Salt solution and the third was placed into a 2%Starch solution. (Keep in mind -  a NORMAL potato cell contains approximately 2% starch.)



Potato in test tube

We then made predictions on if the piece of potato would weigh more, less, or the same after it has sat in each solution and what type of solution we would consider each to be.  There were the results we got.

Test tube	Gained or lost mass	Type of solution
1 – Pure water	Gained	Hypotonic
2- 10% Salt Water	Lost	Hypertonic
3 – 2% Start Solution	Stayed the same	Isotonic

After that I moved into a demonstration that once again showed different types of passive transport.  Look at the pictures below and read the descriptions to see what happened.

First we took our everyday simulated
unfiltered blood

We placed that into dialysis tubing
 (A semi-permeable membrane)

We placed that into a beaker of water to see what would happen

And VOILA - we have simulated Urine!
watch the following video to see
what actually happened here!