1. Materials: worksheet
Which solution is more concentrated: A glass of water with 5 spoonfuls of sugar dissolved in it or a glass of water with 2 spoonfuls of sugar dissolved in it? Why?
What does it mean to be a selective college?

2. Announcements
*If you have not made up the unit 3 test, you must set up an appointment with me to do so. *If you did not complete the work from Monday, Tuesday, or Wednesday, talk to me to get your make up assignments.

3. SB1d: Explain the effects of water on life’s processes
SB1d: Explain the effects of water on life’s processes. (osmosis, diffusion). Essential Question: How do living things maintain balance as the world around them changes?

5. Diffusion Lab

6. Pre Lab: What happens when you spray air freshener in a room??

7. Introduction: In this lab, you will observe the diffusion of a substance across a semi permeable membrane. Iodine is a known indicator for starch. An indicator is a substance that changes color in the presence of the substance it indicates. Watch as your teacher demonstrates how iodine changes in the presence of starch.

8. Procedure
1. Into the plastic bag add about 1 level teaspoon cornstarch. Fill with about half a cup of water. Hold the bag shut and shake gently to mix. Finally, tie the bag shut so nothing can escape 2. Into the clear plastic cup, fill to top of the ridges with water and add 30 drops of iodine liquid. 3. Put the plastic bag containing the cornstarch solution into the iodine solution so the part filled with the cornstarch solution is submerged in the iodine solution. 4. Wait about 15 minutes. 5. While you are waiting, fill in the table and observations.

9. SUmmary
*How does the size of particles affect their rate of transport? *In your own words, define diffusion. *In which direction do particles move during diffusion?