What Is Osmosis?

Bag 1 was 10 mL and filled with dH2O and submerged in dH2O, resulting in being isotonic solution. Bag 2 was 10mL and filled with 20% sucrose, which was submerged in dH2O, resulting in a hypertonic solution. Bag 3 was 10mL and filled with 40% sucrose and was then submerged in dH2O, resulting in a hypertonic solution. In the sac containing no sucrose, just dH2O, there was no net movement; it maintained its initial mass of 16g throughout the 45 minute experiment, meaning it had 0% mass change (see Table 1). Bag 2 was the sac containing 20% sucrose and its mass was increased throughout the experiment and its final total mass change percentage was 7% (see Table 1). The sac containing 40% sucrose had the greatest mass change over the forty-five minute time period (see Table 1). The results in Table 1, coincide with the Graph 1. The sac filled with 0% sucrose had no mass change, therefore has 0 as its rate of osmosis (Graph 1). The sac with 20% sucrose had a rate of osmosis of 0.027g/min, making it the second biggest rate of osmosis. The sac containing the 40% sucrose had the largest rate of osmosis, being 0.098g/min (Graph 1). A table was added to fully understand rate of osmosis (refer back to Graph

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 Diffusion and Osmosis Lab determines the molarities of various sucrose solutions based on change in mass. Using table sugar in different amount of molar concentration 0.0M, 0.2M, 0.4M, 0.6M, 0.8M and 1.0M. The molarity of the solution of the sucrose solution in the dialysis tubing determines the amount of water that either move into the bag or out the bag, which also means its mass changed.

Using the graduated cylinder, measure 20mLs of the stock sucrose solution and 180mL of water to create a 3% sucrose solution and place it into the 250mL beaker (beaker #2). Place bags #1‐3 (red, blue, yellow) into beaker 2 and bag #4 (green) into beaker 1. Allow the bags to sit for one hour. After allowing the bags to sit for one hour, remove them from the beakers carefully open the bags, noting that often times the tops may need to be cut as they tend to dry out. Measure the solution volumes of each dialysis bag using the empty 250 ml beaker.

I. Abstract The purpose of these experiments were to examine the process, and subsequent effect, of osmosis and diffusion, in relation to weight and solute concentration. Osmosis was observed through the use of potato disks soaking in varying concentrations of distilled water and sucrose. Diffusion was observed through the use of a solution-filled dialysis bag soaking in a different solution.

Dialysis tubing works as a replica of a plasma membrane in the cell. Therefore, the results we see in our test corresponds to how a cell membrane diffuses liquids in a solution. Our bags were filled with 10ml of sucrose at different concentrations; 1%, 10%, and 20%. We had two bags of the sucrose at a 1% concentration since we will be using it for both beakers in the experiment. A dialysis bag that has a higher concentration of sucrose than the solution in the beaker would have to be losing its initial mass throughout

The dialysis bag that contained the greatest net movement of water going in or out of one individual bag turned out to be bag “D”. Bag “D” weighed 11.3 g at the start of the experiment before being placed into the sucrose solution. At the end of the 60-minute time frame, bag “D” weighed 15.7 g. As a result, that means that overall bag D increased therefore making it a gain and letting in more of the sucrose solution that was presented around the bag itself. The hypotheses that were conducted in the beginning both were accepted and rejected. The hypothesis for bag A was rejected because it was hypothesized that there would be a loss of weight but throughout each 15-minute interval, the weight increased from 10.7 g at 0 minutes, to 11.2 by 30 minutes and then decreased to 10.8 g at the 60-minute mark.

The movement of materials through a dialysis membrane was conducted in this experiment. In this experiment, dialysis tubing was used to model a semi-permeable membrane. Glucose and starch solutions were placed into the dialysis tubing, which was placed into the beaker that contained water and 35 drops of iodine (initially only 20 but 15 were added). The solution in the beaker tested negative in the glucose test. The initial color of the glucose and starch in the tubing was cloudy and translucent, and the initial color of the liquid in the beaker was a translucent yellow orange. After a few minutes of sitting in the beaker, the liquid in the dialysis tubing had become a purple color and the liquid in the beaker became a darker yellow. Iodine

Transport is the way particles move in and out of the cell. There are two types, active and passive transport. Passive transport includes diffusion, facilitated diffusion, and osmosis. Active transport includes endocytosis, exocytosis, and a protein pump. Both types are used for moving substances through the plasma membrane of a cell.

In this experiment, the dialysis bags was used to simulate a cell membrane. By setting different concentration of solution inside and outside the dialysis bags, osmosis occurred. Therefore, any increase in mass of dialysis bags indicated that water passed the dialysis bags in order to reach dynamic equilibrium. The hypothesis that the change in mass of the dialysis bags increased as the concentration of solution increased was tested.

The idea behind this experiment is to know how does relative concentrations of solutes affect the direction of osmosis.  Osmosis is the diffusion of water through a membrane.  Apparently, for this experiment, the dialysis tube would play the role of a cell membrane since it contains small pores.  These pores would distinguish which liquids are permeable and which ones are not.  The liquids that are going to be used for this experiment includes sucrose solution and water.  My hypothesis and prediction for this experiment is that the dialysis tube that contains water in and water outside of it will not have a change in mass.  While the dialysis tube that contains water in and sucrose outside of it will eventually lose mass.  In addition, the

Thereafter, the dialysis bags were placed with their corresponding numbers. The dialysis bags were weighed in 20 minute intervals for an hour. When measuring the mass of each bag, excess fluids were wiped off, and the bag was placed on a scale to measure the mass and placed back in the beaker. After the experiment, the bags were disposed and work space was

After the first 15 minutes the data is showing that there is movement between the dialysis bag and the hypotonic water. At this point it was indeterminate as to if the sucrose solution moved into the water by diffusion or not. We noted that the dialysis bag had gained weight at each 15-minute interval. At each interval the weight gain was slightly less from the previous weight gain. The most weight gained was in the first measurement when the gradient was the highest with the weight of the dialysis bag increasing 2.1grams with a 10.16% change.

Larger differences between the concentrations or water potential of the solutions results in a steeper concentration gradient, meaning a faster rate of osmosis. In effect the concentration outside of any cell is proportional to

1.1 Osmosis is the diffusion of water molecules through a semi-permeable membrane from the area of low concentration of solute to the area of high concentration of solute.