Ap Biology Lab Report

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Diffusion and Osmosis Through Dialysis tubing

We did this experiment to test the diffusion of different substances through dialysis tubing. We used what we knew about diffusion to make predictions on what we thought the mass of the dialysis tubing to be after submerging them for 30 mins and we knew that diffuse occurs from highest concentration to lowest concentration.

Since the dialysis tubings are filled with different substances than what they are being put into then they should all gain or lose mass. If the dialysis tubing is submerged in different substance than what is in the tubing then some of the dialysis tubings will lose mass and some will gain mass.

To begin this experiment we filled 5 dialysis tubings with one of the five substances: water, egg white, NaCl, glucose, or sucrose. The equipment used was: 5 dialysis tubing, a scale, bekers, water, egg white, sucrose, glucose, NaCl, and 5 cups. We put the five dialysis tubing filled with one of the five substance into a cup filled with one of the substance: water, egg white, NaCl, glucose, or sucrose. Then we let them sit in there for 30 mins then took them out of the cups and remassed them.

Our results were:

Original Mass of dialysis tubing
Water Sucrose Glucose

NaCl
Egg White

9g

9.8g

10.4g

9.8g

9.4g

Our substance combinations were:

water in water-water in the dialysis tubing submerged in a cup of water

sucrose in egg white-sucrose in the dialysis tubing submerged in a cup of egg white

glucose in NaCl-glucose in the dialysis tubing submerged in a cup of NaCl

NaCl in sucrose-NaCl in the dialysis tubing submerged in a cup of sucrose

egg white in glucose-egg white in the dialysis tubing submerged in a cup of glucose

Post Submerge
Water Sucrose Glucose NaCl Egg White

9g

11.7g

11.8g

8g

8.7g

The dialysis tubing did let some of the different solutions in but not all of them. Most of the dialysis tubing gained mass and some lost some mass as well. We found that the substances go from an area of high concentration to an area of low concentration. The data supports our purpose of doing this experiment to find out what happens when a substance in a dialysis tubing is put into a cup of a difference substance to see which ones gain mass and which ones lose mass. A pattern of the data is that the control group did not gain or lose mass. Two of the substances gained mass and two of the substance lost mass. Our results proved our hypothesis that some of the dialysis tubings would gain mass and some of the dialysis tubing would lose mass. Because two of the dialysis tubings gained mass and two of the dialysis tubings lose mass it just shows that the substances went for an area of high concentration to an area of low concentration.

A few errors of our experiment is that we could have not used enough of the substances in the dialysis tubings or we could have left the dialysis tubings the cups of substance for a long amount of time which could have changed our results majorly because the more time the dialysis tubings sit in the cup of substances the more they had time to diffuse.

Osmosis through Dialysis Tubes

We performed this experiment to see how water moves across a semi-permeable membrane. We filled the dialysis tubes with different Mole concentrations of sucrose, and we used our knowledge of osmosis to figure out the different concentrations. If the dialysis tube increases both in size and weight, then that dialysis tube had the highest mole concentration of sucrose.

We learned that during osmosis, a form of passive diffusion which means that it requires no energy to move across the membrane, water will always move to the area where the water concentration is lower, so if the sucrose has a high mole concentration then the water will move into the bag since there is less water...
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