Investigate the Effect of Varying Solution Concentration on Osmosis in a Potato Chip
Prediction
A definition of osmosis is: 'the movement of water molecules from an area of high water concentration to a low water concentration across a semi-permeable membrane' (Oxforddictionary 2000).
In a high concentration of water the amount of solute (e.g. sugar) is low. These solutions are usually known as a dilute or weak solution.
But in a low concentration of water the amount of solute (e.g. sugar) is high. These solutions are usually known as concentrated or strong solutions. When a weak solution and a strong solution are separated by a partially permeable membrane, the water will move from the area of high concentration to the area of low
…show more content…
Using this information, I have come to the prediction that with a high concentration of sucrose in the water, the mass of the potato will decrease and the cells will become plasmolysed. In a low concentration of sucrose the cells will become turgid.
Preliminary work
I have based my prediction on a prelimary experiment we did amongst our class, this experiment involved us placing potato chips into various concentrations of sucrose solution and observing the potato's change in mass according to the solution they were placed in.
Carrying out a preliminary experiment helped me to decide how long to leave the potato chips in the sucrose solution. In the preliminary I left them for 24hrs however I found this an insufficient time and this helped me to decide on leaving the potato chips for 2hrs in the final experiment. Preliminary Experiment Results
-----------------------------------------------------------
solution mass before mass after 24hrs change in mass
0 1.5 2 0.5 0.1 1.7 2 0.3 0.2 1.6 1.8 0.2 0.3 1.6 1.9 0.3 0.4 1.5 1.9 0.4
-----------------------------------------------------------
Variables
In order to create a fair test, certain aspects of the experiment will have to be kept the same whilst one key variable is changed. In my experiment, I have chosen to
My prediction is that as the concentration increases, the potato cell will lose more weight. This is because of the osmosis of water particles from the potato cell cytoplasm to the solution, resulting in a loss of weight. As the concentration decreases, the potato will lose less weight until a certain point where the osmosis of particles in and out of the potato cells will be equal. I also predict that as the salt
As the Concentration of the Sucrose Solution decreases, the more the potato’s mass increases. This is due to the solution being hypertonic. So, as the solute concentration gets lower, the potato’s water concentration will get higher, therefore more water particles from the solution will absorbed by the potato. Some changed very little in mass because the concentrations of the H2O molecules in the potato and outside the potato were equal. This equality in concentration is called Isotonic.
The lab for this paper was conducted for the topic of osmosis, the movement of water from high to low concentration. Five artificial cells were created, each being filled with different concentrated solutions of sucrose. These artificial cells were placed in hypertonic, hypotonic, or isotonic solutions for a period of 90 min. Over time, the rate of osmosis was measured by calculating the weight of each artificial cell on given intervals (every 10 minutes). The resulting weights were recorded and the data was graphed. We then could draw conclusions on the lab.
Osmosis is the diffusion of water across a membrane to create an equilibrium between the levels of concentration of a solute both inside and outside the cell. In this case the solute will be sugar as the potato core will be immersed in sucrose solution.
Figure 1: Percentage change in potato tuber mass vs. sucrose concentration. The percent change in mass decreased as the sucrose concentration increased. Relative osmotic concentration was measured as the percent change in mass of sucrose concentration over one hour.
Osmosis is a special type of diffusion. It is the diffusion of water molecules across a semipermeable membrane (a membrane that allows for the diffusion of certain solutes and water) from an area of higher water concentration to one of lower water concentration. For example, if a 1 M aqueous starch solution is separated from a .5 M aqueous starch solution by a semi-permeable membrane, then water molecules will move from the .5 M aqueous starch solution (higher water molecule concentration) toward the more concentrated 1M starch solution (lower water molecule concentration) until an equilibrium of water molecules exists between the two solutions. Since the semi-permeable membrane did not allow for the passage of starch molecules, the 1M-starch solution will gain in volume as the water moves in (Figure 3).
By definition, osmosis is the diffusion of water across a selectively permeable membrane in response to gradients of concentration, pressure, or temperature (G. Audesirk, T. Audesirk, B. Byers). Diffusion is the passive movement of molecules or particles along a concentration gradient, or from regions of higher to regions of lower concentration (Diffusion). In the experiment, osmosis and diffusion occurred where the results indicated a change in mass when the egg was placed in different concentrations of corn syrup solution. My hypothesis stated that if the concentration of the solute is lower than the solvent, then the egg will shrink in size. With a majority of the results decreasing in weight, my hypothesis was proven to be correct.
Van’t Hoff’s Law suggests that the osmotic potential of a cell is proportional to the concentration of solute particles in a solution. The purpose of this experiment was to determine if there are any differences between the osmolalities, the no-weight-changes of osmolalities, and the water potentials of potato cores in different solutions of different solutes. The percent weight change of the potato cores was calculated through a “change in weight” method. The potato core’s weight was measured before and after they were put into different concentrations of a solute for 1.5 hours. In our experiment, there were no significant differences from the osmotic potentials of our results and the osmotic potentials of other scientists work. Ending with chi square values of 2.17 and 2.71, and p values of 0.256 and 0.337, concluding that there is no difference in water potentials of potato cores in different solutions of different solutes at varying concentrations.
Effect of Sucrose Solution on Osmosis Aim: The aim of the experiment is to show how varying the concentration of sucrose solution affects osmosis by changing different molar solutions of sucrose and water and how it affects the potato. Introduction: In this investigation I will be exploring the effect of varying concentration of sucrose sugar solution on the amount of activity between the solution and the potatoes. Osmosis is the movement of water molecules across a partially permeable membrane from a high water concentration to a low water concentration.
After we completed our experiment, we used the equation, Y=-iCRT, where i was the ionization constant (1), C was molarity (.2, .4, .6, .8, 1), R was the pressure constant (.0831), and T was the temperature of the room in Kelvin (294 degrees). The hotter the temperature of the room, the faster the experiment will go. In the experiment, when the molarity of sucrose was at .4M, the molar concentration of sucrose had a water potential that was equal to the potato tissue water potential, meaning that the potato cell has reached equilibrium. The initial and final mass of the potato at .4 M was .3g, so there was no change in mass.
The Graphs below show the percent changes in mass for both the class averages and our group's averages:
The purpose of this experiment was to investigate the effect of the change in concentration of sucrose on the rate of osmosis in cylinders of potatoes.
Osmosis is the movement of water molecules from high concentration to low concentration through semipermeable membranes, caused by the difference in concentrations on the two sides of a membrane (Rbowen, L.). It occurs in both animals and plants cells. In human bodies, the process of osmosis is primarily found in the kidneys, in the glomerulus. In plants, osmosis is carried out everywhere within the cells of the plant (World Book, 1997). This can be shown by an experiment with potato and glucose/salt solution. The experiment requires putting a piece (or more) of potatoes into glucose or salt solution to see the result of osmosis (a hypertonic type of solution is mostly used as it would give the most prominent visual prove of
Within every cell, a movement of a solvent occurs through a semipermeable membrane to equalize the concentration of solute on both sides of the membrane. The diffusion of water across the cell’s membrane down to its concentration gradient is called osmosis. In this case, the concentration gradient is the difference of density between one side of the cell membrane to the other. Since the cell’s membrane is permeable, particles can flow freely in and out of the cell, but the net flow will be strong in the direction of lower concentration until the system has reached a stage of equilibrium, the point at which both sides of the membrane are equal. In the
Diffusion is the passage of solute molecules from an area of high concentration to an area of low concentration (Campbell & Reece, 2005). An example is ammonia diffusing throughout a room. A solute is one of two components in a chemical solution. The solute is the substance dissolved in the solution. The solvent, the other component, is any liquid in which the solute can be dissolved (Anderson, 2002). Diffusion requires little or no energy because molecules are always randomly moving; this is due to their kinetic energy. Diffusion occurs only when there is an imbalance in the areas of