Diffusion And Osmosis Lab Report

Hypothesis: If we add higher concentrations of sugar to the dialysis tubing, then the net movement of coffee into the dialysis tubing will increase.

We hypothesize that as the solute concentration increases, more water will diffuse into the dialysis tubing (shown by a greater percent increase in mass).

The dialysis tubing will be clamped at one end in order to fill it and then clamped at the other end to seal the filled bag. If the bag is not soft and floppy, the experiment will not work. Blot a bag with a paper towel to absorb the moisture and weigh it, if this blotting process is not done it could interfere with the weight readings creating inaccurate information. After the bags of the solutions are prepared, they will be placed into five different beakers with different solutions. Beakers 1-4 will be filled with tap water and the fifth beaker is filled with 40% sucrose and water. Fill each beaker with just enough water or solution so that the bag is covered and place the bags in the beakers simultaneously and record each time. Every 10 min the bags are to be taken out, blotted, and weighed again before returning them back into their respective beaker for another 10 min. The process is repeated until you have reached 90 min. The weights should be recorded in grams (g).

A major determinant of diffusion in a biological system is membrane permeability. Small, uncharged molecules pass through cellular membranes easily, while most and/or charged molecules cannot pass through the membrane. The movement of water across a selectively permeable membrane, like the plasma membrane

1. The relationship between rate of diffusion/ osmosis, volume, and surface area can be easily seen and analyzed through the data that was collected from procedure one: Surface Area and Cell Size. Phenolphthalein is a dye-material in this lab that was used to determine whether a substance was an acid or base. This could be told as the phenolphthalein changed into a murky. Muddled and clouded color when mixed with acids. When the chemical aid was mixed in with a base, the color

In order to test the predictions of the hypotonic, hypertonic, and isotonic hypothesis for the solution  made during the study,  four samples of sucrose were taken and placed into two different beakers each containing a different concentration. Beaker 1 is  250- mL and contained 150-mL of 10% sucrose with dialysis tubing A, while beaker 2 (a large bowl) contained 1% sucrose, with dialysis tubing  B, C, and D. Tubing A contained 10-mL with 1% sucrose. Tubing B

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration until equilibrium is reached. Osmosis, however, is the movement of water according to its own concentration gradient across a selectively

Though the theory following the hypothesis is correct and the experiment was carried out with as much attention as possible in a high school laboratory, the results obtained were still indicative of a few errors and did not support the predicted hypothesis. From the results obtained it can be concluded that as the concentration of sucrose increases the average percentage change in mass decreases. This is because the salt concentration inside the potato cubes of 10%, 15% and 20% concentration is less that in the salt concentration on the sucrose solution, thus the three cubes submerged in the 10% - 20% concentrated solution lost mass (hypertonic). However the cube submerged

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).

There were several steps completed to prepare for the experiment. Three dialysis tubes were filled with approximately the same volume of distilled water and then were tied shut. The initial mass (in grams) of the tubes was taken using a triple beam scale. I then filled three 500 mL beakers with 400 mL of water each and dissolved different masses of solute (table sugar) in each beaker in order to make 5%, 10%, and 20% solutions. The beakers were labeled accordingly, and then 20 g, 40 g, and 80 g (respectively) of table sugar was weighed out using a digital scale and placed into the corresponding beakers. The sugar was stirred in using a stirring rod until all of the solute was completely dissolved.

From figure 2, we can observe diffusion taking place.’S’ represent starch, ‘i’ represents iodine and ‘g’ represent glucose. As initially, 1 inch dialysis tube consists of iodine and glucose and 3 inch dialysis tube consists of starch. However, after 1 hour, the iodine molecules got diffused into 3 inch dialysis tube and also the water in the beaker turned slightly cloudy in the final stage.

The class data that was received supported the group members’ hypothesis that the rate of osmosis will increase if the sucrose concentration increases as well. The trend line that was received from the data also supported the hypothesis because it increased as the sucrose concentration increased. The initial weight gain percents were all different because all of the groups’ sugar concentrations were not completely identical. The method used wasn’t entirely accurate because there could’ve been some flaws such as some bags weren’t secured enough and might have leaked sucrose into the de-ionized water causing the results to be different. The bags might have not been washed thoroughly which could have ultimately allowed sucrose into the de-ionized water. The results could have been more accurate if the baggies were left in the

Cells are always in motion, energy of motion known as kinetic energy. This kinetic energy causes the membranes in motion to bump into each other, causing the membranes to move in another direction – a direction from a higher concentration of the solution to a lower one. Membranes moving around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration, until they are equally distributed (Mader & Windelspecht, 2012, p. 50). Cells have a plasma membrane that separates the internal cell from the exterior environment. The plasma membrane is selectively permeable which allows certain solvents to pass through

Then, each group of students received the necessary materials to complete the experiment. When the students received the cups, they labeled cups to distinguish between the salt solution, distilled water, and control group. After weighing the cups and finding the mass of the cucumbers, the students poured 50 ml of water in one cup, 50 ml of salt solution in the other, and left the control cup empty. Then, the students placed the cucumbers into the cups and waited 30 minutes for the results. After the 30 minutes, the students removed the cucumbers from each solution and dried the cucumbers with paper towels. The students then weighed the cucumbers again and recorded their results. Lastly, the students found the difference from the original mass of the cucumbers and recorded their results.

The movement of water molecules across a semi-permeable membrane is the process of osmosis. If there is a solute and a solvent, each containing different concentration levels, then the water would move along its concentration gradient until each side of the membrane are equal. The water moves because the membrane is impermeable to the solute and the solute concentrations may differ on either side of the membrane. Water molecules may move in and out of the cell, but there is no net diffusion of water. Water will move in one direction or the other, and this is determined by the solute or solvents concentration levels. If the two solutions are of equal concentrations, they will be isotonic. If the concentrations are unequal, the