1. OSMOSIS and DIFFUSION

2. Molecules are always moving
Molecules move randomly and bump into each other and other barriers

3. Diffusion
Molecules in solution tend to slowly spread apart over time. This is diffusion.

4. Diffusion
Movement of molecules from an area of high concentration to an area of lower concentration.
Factors that affect the rate of diffusion: size of molecules, size of pores in membrane, temperature, pressure, and concentration.

5. Diffusion [High] [Low] concentrated, high energy molecules
diffuse, low energy molecules

6. Diffusion will continue until equilibrium is reached
Diffusion will continue until equilibrium is reached. This means there will be an equal distribution of molecules throughout the space. This is why food coloring moves throughout a beaker of water; why odors smell strong at first and then disappear over time.
Equilibrium, a result of diffusion, shows the uniform distribution of
molecules of different substances over time as indicated in the
above diagram.

7. Which molecules will diffuse in each of the figures below?1 2 3 4 5 6

8. ANSWERS 1 2 3 4
No Movement 5 6
No Movement

9. Osmosis
Osmosis is the movement of WATER across a semi-permeable membrane
At first the concentration of solute is very high on the left.
But over time, the water moves across the semi-permeable membrane and dilutes the particles.

11. Over time molecules will move across the membrane until the concentration of solutes is equal on both sides. This type of solution is called ISOTONIC.

12. Below are examples of red blood cells in different types of solutions and shows what happened to the red blood cells.

13. PLANT CELLS Hypotonic Solution Hypertonic Solution
Turgor Pressure builds in the cell and causes osmosis to stop
because of the rigid cell wall.
Plants will wilt when cells
lose water through osmosis.

14. As viewed under the microscope
ELODEA CELLS
As viewed under the microscope

15. THE END