Rate Of Osmosis

The class average, or what we got as a class, was 2.333%. Three of the groups had hypotonic solutions, and the other two had hypertonic. Which is about the same as other studies found. One study from slideshare.net got 2.29% concentration. When their potato was placed in a 0% solution, there was a 2.52% change in weight, and gained 1.91g. Our potato had a 4.74% change in weight, and gained .61g. Once other study from slideshare.net got around 1.75% for their concentration of their potatoes. These all could have been different because of the water, kind of potato, size, shape, and other

The purpose of this lab was to determine the effect of solutions with different salt concentrations on the mass of a potato slice. The data collected and analyzed in this experiment seems to support the hypothesis, which stated that the mass of a potato slice would decrease, as the salt concentration increased. This can be evidenced in Graph 1 where the downward slope of the data shows a negative correlation between salt concentration and average percent change.

In activity 2, the experimenters first cut potatos and carrots into similar pieces. Then they weighed each core and measured the length of each core. Next, they put one carrot core and one potato core in each of the mystery sucrose solutions. After 30 minutes, the experimenters re-weighted the carrot and potato cores. Then, they culculated the change in mass and percentage change in mass of each core.

A concentration gradient is the difference between the concentration on the inside of the membrane and the concentration of the outside. This indicates that there is a high-water concentration in one area and a lower water concentration in another. Similarly, osmosis is the movement of water molecules through a selectively permeable membrane from a higher to lower concentration. The data above contains a hypertonic solution as there was a decrease in mass for potato pieces 1, 2, 3 and 4 from its original mass. The decrease in mass was a result of the concentration gradient as there was a difference in concentration of solute from the inside to the outside of the cell wall. In an hypertonic solution, the concentration of all dissolved solute is greater than the concentration in the cell. Since, water has a higher concentration within the cell, there is a net movement of water out of the cell. Leaving the cell through the process of osmosis and down its concentration gradient. However, water moves from a lower to a higher solute concentration.

However, there are also some errors in this experiment. Firstly, the potato pieces were not exactly the same size despite the care taken to cut them. A solution to this would be to use a form cutter, which would cut exactly equal shapes. Secondly, the temperature is not exactly a constant variable as it fluctuated throughout the experiment as the test tubes were even put in a refrigerator with a much lower temperature than in the room. A solution for improving could be to place the test tubes into an electric cooler in the beginning to make the temperature stable and put potato pieces when the test tubes are in the cooler. Also, errors could be decreased by using a more precise beaker. Finally, repeating the experiment several times would allow as to take the average results and have a more adequate result.

With different percentages of salt. Let them sit for 30 minutes and took them out. At the end we found that the potatoes lost water due to the salt. INTRODUCTION

My lab was based on one very important question, how can the weight of potatoes change if

The result showed the affects of osmosis, where particles moved to achieve equilibrium. The 0.2 M sucrose had a +8.37% change in mass as a class average and our group and +9.52%. The initial mass for these carrots were 2.1g and became 2.3g when the 2 days had ended. This happened because of the same reason for the 0.0 M sucrose, where the concentration of particles were greater inside the cell compared to the outside of the cell, causing the water molecules moving into the cell through the semi permeable membrane. However, the solution the carrots were dunked into had a 0.2 M sucrose, unlike the first solution. This caused the mass of the carrot to change less because there was already some particles outside of the cell, allowing for equilibrium to become reached a lot faster than 0.0 M sucrose. In 0.4 M sucrose, there was a class average of -2.34% and we had -4.76%. The initial mass was 2.1g with a final mass of 2.0g. This was the first solution to have a negative percentage change in mass from the other six. There was a decrease in mass of the carrot because water had moved from the carrot sticks into the solution around is trying to achieve equilibrium. The water molecules had moved from high concentration into lower concentration, moving our of the carrot cells, causing them to

The solutions of 2% and 10% both reached dynamic equilibrium as neither had lost nor gained water during the experiment, This indicates that the results may have been inconclusive because two, widely various solutions could not have both reached dynamic equilibrium with the potato cell. This leads to the idea that there were a few errors made while performing this experiment, which most likely had an effect on the results, causing them to be non-reliable. Firstly, the test tubes had not been properly cleaned before the experiment took place. This caused a strange smell and a colouration of the potato tuber, it may also have increased or decreased the osmotic potential, though this cannot be known as it is not known what chemical residue may have been left in the test tubes. Secondly, the potato cells had been left in for three days instead of the recommended 24hrs. This mistake may have caused the soft, sogginess of the potato which rendered it difficult to pat dry and handle. During this part of the experiment, pieces of the cells were broken and lost down drains or stuck to the paper towel, as well as many still containing much excess water. Because of this, the weights measured could be inaccurate and therefor unreliable. Based on the data found by Clemson University Student Robert.

We find that having heavy concentrated bag of molasses does make the rate of osmosis much faster. The more molasses there are in the bag the more the “cells tend to lose water because the water travels from an area of high concentration (inside of the cell) to an area of lower concentration (outside of the cell)” (Saucedo, 2012) which is also hypertonic which moves the cells faster. We do Accept our hypothesis since the result has shown that the more molasses the bag contain the faster the rate of osmosis.There are a lot of situation that could go wrong with this experience because one of thing that could go wrong with this experiment is that we could have measure things wrong especially with the molasses because the solution is extremely thick

I think that the increase of the concentration of the solution in the test tube the lower the mass of the potato will be. I came

This experiment went through a series of steps, starting with placing 100mL of different concentrations of sodium chloride (NaCl) in separate beakers. Sections of potato were punched out, then dried and recorded for initial weight. Five were placed in each concentration of the sodium chloride, and left to sit for an hour and a half. The mixtures were swirled about every fifteen minutes to prevent shells of water from building up around the core and causing error in the results. After the hour and a half, we removed the potato sections, dried them and then weighed them for the final weight.

In order to determine the molarity of the potato tissue we placed the potato tissue into different concentrations of sucrose (0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6M), we measure the percent change in weight and we measured the different molarities of sucrose. We placed potato cores into different concentration of sucrose, and then we measured the weight of the potato cores before and after the experiment using a balance. Our hypothesis is supported by our data by the decreasing of our graph, in graph 1 and in table 1.

The previous prediction was proven to be correct. The negative line of best fit that was illustrated onto the graph did not go through all of the data points and suggests random error. The point where the line crosses at 0% change in mass at the horizontal axis, the solution of water molecules in the potato cell is equal to the concentration of sucrose. Therefore, the concentration of sucrose is isotonic with the cytoplasm of the potato cylinder. Thus, there is no net movement of water by osmosis

all be cut out of the potato using a cork borer and will all be cut to