Monday, September 23, 2013

Class 4 & 5: Diffusion and Osmosis

In classes 4 to 5 we did a large lab on demonstrating diffusion and osmosis. First we went through all of the important terms and background information.

Definitions:

Diffusion: Molecules travel from an area of high concentration to low concentration, such as perfume spreading through the air.

Osmosis: Transfer of water molecules from area of high concentration to low concentration through a semi-permeable membrane like a cell. Stopping when equilibrium is reached.

Hypertonic: A solution that where there are more solvent than solute

Hypotonic: Opposite of hypertonic, where a solution has more solute than solvent

Isotonic: Equal amount of solute and solvent


LAB:

Part 1: Starch diffusion through a cell (fake cell made with dialysis tubing)
Part 2: Osmosis of 6 different concentration fake cells
Part 3: Determining the solute % of 4 different potatoes through osmosis of its cells
Part 4: Determining the solute % of 4 different energy drinks (same as above basically)
Extra Part 5: Diffusion of benedict's solution into a NaCl cell. Calculate percent diffusion

For a complete formal lab report with data visit:

Pictures of the lab:


Potatoes!


6 Different concentration solutions!


6 fake cells!


More potatoes!


Cell after osmosis




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