2. I will cut five cylinders out of my living tissue, with equal mass and similar surface area. I will record their mass, so I can compare the mass of the tissue after the experiment.
3. I will then add one piece of living tissue to each test tube, and start a timer so I can monitor how long the tissue is exposed to the solutions.
4. After 30 minutes, I will drain the liquid from all my test tubes, remove my sample, and place it on a paper towel to absorb excess liquid which may affect its mass.
5. I will then record the new masses of my living tissue samples, and note any observations on its change in flexibility.
Equipment
Test tubes
Test tube rack
Water bath (40°)
Knife
Scales
Paper towels
To ensure that this experiment is fair, I will be using an equal amount of solution and living tissue. The solutions will all be heated to the same temperature, and kept at that temperature constantly before the experiment begins. The experiment will also be timed to ensure an equal exposure to the solutions. My living tissue samples will be of similar masses and have similar surface areas also and I will be absorbing excess liquid from my tissue samples before weighing them.
I hope to take around five results for my experiment, over a relatively large range, to make differences more apparent.
To make sure my results are reliable I will repeat my test several times, to ensure my results aren’t a fluke.
I expect my results to show that the tissue exposed to the dilute solution, will increase the mass of the tissue, and make it more turgid. In the concentrated solutions, the mass of the living tissue will decrease, and it will become more flaccid. I also predict that the more concentrated the solution, the more the mass will decrease.
These results should occur, because if the living tissue is in a dilute solution, then there would be fewer water molecules in than tissue, than in its surroundings, so water would diffuse from the solution, into the tissue, which would increase its mass. This would put more pressure on the cell wall, making it firmer or more turgid. In the concentrated solution, there are more water molecules in the living tissue, than in the solution, so osmosis should occur the opposite way, and water molecules should diffuse from the tissue into the solution. This would decrease the mass of the tissue, which would put less pressure on the cell wall, so the tissue would become flaccid.
I did a trial run of my experiment, and found my results to be as I expected, but not significantly. When I do my proper experiment, I will leave my living tissue in the solutions for longer, (45 minutes as opposed to 30 minutes), so my results are more apparent. I will also use a smaller borer to make my cylinders longer and thinner, I hope this larger surface area will increase the rate of osmosis.
These are the results of my trial run:
