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7. What happens if you start with hot water? Ice cold water? Salt water?

8. What happens if you cut the celery stalk at the base high enough so it
straddles two cups of different colors?

Cell Walls of Cotton

In this experiment, you were able to get the cotton balls in the water
because cotton balls are mostly air. Even the strands of cotton are mostly
air, because the strand is just the cell wall from the cotton plant.

1. Fill a glass of water so it is completely full
2. Take a cotton ball and try to add it to the glass of water without
spilling any water. (Hint: Scrunch up the cotton ball, and slowly get it
wet, then allow it to fall in.)

3. Get as many cotton balls into the cup as you can

Osmosis in Potatoes

One way substances can get into a cell is called passive transport. One
special kind of passive transport is osmosis, when water crosses into the
cell. This experiment allows you to see the process of osmosis in action. Are
you ready?

This experiment allows you to see the process of osmosis in action

1. Cut two thin slices of potato. The pieces should be about the same
thickness and be slightly flimsy.
2. Place both slices in separate glasses of water
3. Add salt to one of the glasses.

4. Wait about 15 minutes.
5. Pull out the two pieces of potato and make observations.

Questions
1. How was the concentration of salt different in each cup?
2. Which direction was water flowing in each cup?

3. Why did one potato become stiff, while the other became flimsy?

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