Diffusion lab

Purpose: The purpose of this lab was to study the diffusion of molecules

Through starch, iodine, sugar, and benedicts.

Hypothesis: I think the starch will seep through the bag and when we pour

the iodine in, it will become lucid in some areas and less in others.


1. dialysis tubing with string

2. pour starch solution into a 50 ml beaker

3. pour in and seal (starch)

4. rinse with water

5.set in water for 10 minutes

7.add iodine for testing

8.throw away bag and wash beaker well

Data and observation: After adding iodine solution to the water the bag

turned a dark black and the water kept it yellow-brown.

Calculations: The similarities and differences in the set up of an actual cell

and the anylize tube is…….

Similar and different


If I added a digestive enzyme to the starch solution inside the dialysis, the

starch would be able to pass through the membrane because the starch would

break down when the enzyme was added.

Conclusion: What I learned from this experiment was to see how a cell

membrane let some molecules pass through and some didn’t, the sugar and

starch. What happened was that when I added the iodine to the water and

the starch solution was inside of the tube. It showed that the water kept a

yellow brown color while the tube had a dark almost black color. Which

means that the starch couldn’t get through and the water could. With the

sugar, when adding the Benedict’s solution it changed colors because the

sugar and water was able to pass freely throughout the membrane. For our

lab the sugar benedict solution did not turn out the way planed. I think

because we did not wait long enough for results.