Osmosis and Diffusion

Osmosis and Diffusion are a type of Passive Transport.

Osmosis and diffusion are a type of a passive transport. This means that when they pass through the membrane, they do not need any energy. This is because they are Some molecules are small enough they can move through on their own. If the molecules are too big to just pass through, they travel through protein channels. When protein channels are used it is called facilitated diffusion.

Testing It Out

Hypothesis:

If a tube of drinking water is placed in a cup of distilled water, the mass of the tube will decrease because the solutes will leave the tube making it a hypertonic solution.

If a tube of drinking water is placed in a cup of clear soda, the mass of the tube will increase slightly because the solution (soda) is more isotonic.

If a tube of drinking water is placed in a cup of dark soda (non-diet), the mass of the tube will increase because the solution (soda) is more hypotonic.

Variables

Independent Variable: type of solution (distilled water, sodas)

Dependent Variable: mass of the each tube

Control Variables: amount of solution, amount of water within the tube, the type of water in the tube

Steps

1. using a funnel, pour 15mL of drinking water into a dialysis tubing. Tie the ends of the tubing with a piece of string. Measure the mass of each tube and record it. Label this tube 1.
2. Repeat Step 1 two more times with separate tubes. Label each of these 2 and 3.
3. Pour 270mL of each solution into three separate cups (be sure to label each appropriately).
4. Put the dialysis tubing into each cup.
5. Let it sit for 24 hours.
6. Take out the tubes and pat them dry (be careful not to squeeze them).
7. Measure the mass of each tube and record them in your data table.