Investigating the Factors that Affect Water Uptake by Potatoes
Plan
Osmosis is the movement of water from a region of a high concentration
to a low concentration of water through a selectively permeable
membrane.
Aim
To find the concentration of the solution in the vacuole of the
potato.
Prediction
I predict that when the potato chip is placed into the water solution,
its mass will increase because that water moves from a high
concentration to a low concentration. When the potato chip is placed
in 100% salt solution, I predict its mass will decrease.
Variables
* Concentration of the salt
* Size of the potato chip
* Time of incubation
* Variety of potato
* Skin on potato chip
* Temperature
* Volume of water
Scientific Explanation
I think that when the potato chip is placed in water its mass will
increase because water moves from a high concentration to a low
concentration. This process is called osmosis which is the movement of
water from a high concentration to a low concentration through a
selectively permeable membrane.
The water is stored in the vacuole in the cell of the potato chip and
as that expands then so does the mass of the potato chip.
Method
The following apparatus were used:
* Scales
* Potato chip
* Water solution
* Measuring jugs + beakers
* Thermometer
* Boiling tubes
* Stop clock
* Knife
* Pipette
Salt Concentration (m)
Volume of water (cubed cm)
Volume of salt solution (cubed cm)
0
30
0
0.2
27
3
0.4
24
6
0.6
21
9
If we say that the right hand side in picture 1 is the potato, and the
Investigation to Find the Water Potential of a Root Vegetable Introduction Water potential is the tendency of water molecules to move from one place to another. Osmosis is the movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane. I will be investigating the water potential of a carrot to find out at what concentration of salt solution (molar dm-3) equilibrium can be sustained between the net movement of water molecules in to the carrot cells, and the net movement of water molecules out of the cells, therefore finding out the water potential of the carrot, and at what concentration of salt solution the movement of water molecules ceases, and what concentration the water is at inside the carrots cells. I will need to include and explain the relevant AS knowledge demonstrated by this investigation. This includes ideas about osmosis, explaining also how this can affect the structure of plant cells, and showing extremes such as plasmolysis.
Investigating Osmosis In A Potato Introduction: "Osmosis is typically defines as the flow of one constituent of a solution through a membrane while the other constituents are blocked and unable to pass through the membrane. Experimentation is necessary to determine which membranes permit selective flow, or osmosis, because not all membranes act in this way. Many membranes allow all or none of the constituents of a solution to pass through; only a few allow a selective flow. In a classic demonstration of osmosis, a vertical tube containing a solution of sugar, with its lower end closed off by a semi-permeable membrane, is placed in a container of water. As the water passes through the membrane into the tube, the level of sugar solution in the tube visibly rises.
Osmosis in Potato Chips Preliminary Experiment to investigate Osmosis 1M Sugar 50:50 0M (water) Initial mass 2.40 2.05 2.34 Final mass 2.01 1.85 2.43 Change in mass -0.39 -0.21 0.09 % change in mass -12.5% -10.5% 3.84% Evaluation From doing our preliminary experiment it enables us to gain a better result for our real experiment. From this experiment we have learnt a few things through trial and error, for example. If we had used a wider variety of concentrations, our results would have been more accurate. By using a syringe to measure the solution we would have also got a more accurate result. We could have also weighed the potato chips more accurately so they were roughly the same size with no skin.
The Effect of Water Concentration on the Mass of Potato Tissue Aim: The aim of this investigation is to discover the effect of water concentration on the mass of potato tissue, and also to investigate the movement of osmosis through potato tissue. Scientific Knowledge: When a substance such as a sugar dissolves in water, the sugar molecules attract some of the water molecules and stop them moving freely. This, in effect, reduces the concentration of water molecules.
7. Remove 6 disks at a time from the petri dish and weigh them using
Osmosis in Potato Tubes Osmosis: Osmosis is the movement of water molecules through a semi-permeable membrane from a high concentration to a low concentration. Diagram: [IMAGE] [IMAGE] Aim: To see the effects of different concentration of sugar solution on Osmosis in potato tubes. Key factor: In the investigation we change the sugar solution from: 0%-10%-20%-30%-40%-50% this is the independent variable; the dependant variable is the change in mass. Prediction: I predict that all the potato tubes in pure water or low concentration sugar solution will swell because water enters their cells by osmosis.
* Note the mass down in the table at the end of the first page.
Factors Affecting Osmosis in Potato Tissue Introduction: I am going to design and modify an experiment used to show osmosis in potato chips in different concentrations of sucrose solution. I am also going to investigate on how potato chips change in volume and weight when placed in different concentrations of sucrose solution. I will also conduct a preliminary experiment before my final experiment. Aim: To investigate the effect of different concentration of sucrose solution on potato chips. Hypothesis: I would expect the potato chips to turn flaccid when they are placed in a strong sucrose solution because the water from within the cells will diffuse out leaving the potato flaccid.
Water Potential of Potato Cells Aim: To demonstrate the Water Potential of Potato Cells. Objectives: · To show the water potential of potato cells using various measured concentrations of a sucrose solution and pieces of potato. · To record and analyse data to verify observed results. · The method and procedure was carried out as per instruction sheet. Observations: The experiment shows that the lower the concentration of the sugar solution, in the Petri dish, the mass of the potato increased.
the same way as it does potato. I would also widen the range of sugar
there would be no flow of water into or out of the cell so the cell
When I am not using them I will place them away from my experiment and
4. Put each group of potato discs in one of the 6 test tubes and watch
The Effect of Salt Solution Concentration On The Mass Of Potatoes Introduction = == == == ==