Osmosis is defined as the net movement of water or any other solutions molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with all areas having an equal concentration.For this particular investigation I think that the lower the concentration of the salt solution in the test tube, the larger the increase in mass of the potato chip will be. This is because the water molecules pass from a high concentration. Therefore, I believe that the chips that are in the tubes containing a higher concentration of water than salt will have a larger mass than chips in tubes with higher salt concentrations. As shown bellow osmosis
Osmosis in PlantsPlants depend on osmosis to move water from their roots to their leaves. Osmosis is also crucial in plants as it protects leaves against losing water through evaporation.In osmosis in plants there are specialized cells called Guard cells which are all along the surface of the leaves. Each pair of guard cells surrounds a stoma or pore, controlling its ability to open to release water. Factors effecting rate of osmosisOsmotic pressureOsmotic pressure is the pressure caused by the difference of solute concentration between solutions separated by a semi-permeable membrane. As osmosis takes place pressure builds up on the side of the membrane where the solvent concentration has increased. This pressure prevents more water from entering the membrane and osmosis stops.PermeabilityPermeability affects the rate of osmosis because if a material is permeable it can allow molecules to pass through quicker than semi-permeable materials as the holes are bigger and can allow more molecules to pass through.
The Essay on Corer To Ensure A Fair Test To Make The Cut Mass Water Concentration
Background Information. I think that this practical will be based on osmosis because, Osmosis is the random movement of water molecules from a high concentration to a low concentration. This will then happen between the chips and the liquid in the McCarthy bottles. This already tells us that the chips will vary in size from the concentration of water. Plan of the Experiment. Method 1 Firstly we ...
Hypotonic condition – When a plant cell is placed in a solution containing lower amount of solute and a higher concentration of water the cell swells up due to the movement of water into the cell. The cell becomes turgid and the rigid cell wall tries to hold this excess amount of water. Isotonic condition – When the plant cell is placed in a solution of similar concentration, water moves across the cell membrane in both the directions. The net movement of water is zero with no change in the cell size.
Hypertonic solution – When the plant cell is placed in a solution containing higher amount of solute and a lower concentration of water the cell shrinks as greater amount of water leaves the cell. The vacuole shrinks and the cytoplasm gets peeled off from the cell wall. Such cell is known as plasmolysed cell.
As shown bellow the effect of Osmosis in plant cell.
Osmosis in Animal cells
Animal cells have a no cell wall to stop them from swelling up. So if animal cells are placed in pure water they take in water by osmosis until the eventually burst. All animal cells have cytoplasm and a cell surface membrane which completely surrounds the cell. Most animal cells also have a nucleus. Red blood cells, however, are unusual and do not have a nucleus. As shown bellow the effect of Osmosis in Animal cells.
Factors that affect osmosis:
What affects the rate of osmosis:There are many factors that can affect the rate of osmosis; these are concentrations of solutions in osmosis, the surface area, temperature, distance, time, pressure, light and dark. Temperature: A faster temperature means a faster rate of reaction. Concentration: Water potential level in osmosis molecules have to move from an area of high water potential to an area of low water potential. Also the are of low water potential will contain more salt molecules than water molecules and the area with high water potential will contain less salt molecules than water molecules, meaning that the salt molecules will move from the area of low water potential to an area of high water potential. This increases the rate of osmosis if the high water potential side and the low potential side have a very different level of water, but it will slow down as they share out the water and salt molecules. Distance: The more distance the molecules need to move across between two sides the slower rate of osmosis will be.
The Term Paper on Osmosis Potato Lab Report Biology 4u
If the concentration of sucrose in the solution is less than the concentration of sucrose found in the potato, then the potato would decrease in mass. The opposite would occur as well, if the concentration of sucrose in the solution is more than that of the potato, then the potato would expand and gain in mass. In conducting this as an experiment, we can determine what the solute concentration of ...
Surface area:For any chemical reaction, if there is a bigger surface area with the reactants, then there is more chance of successful collisions between the particles. In osmosis with this particular experiment, this is the permeability of the potato, whether the water molecules can easily get through the permeable membrane or not during osmosis, the easier for the water molecules to pass through means faster rate of osmosis. The permeability of the potato can be determined by the age of the potato, as older the potato is the less permeable it is, meaning a slower rate of osmosis. It can also be determined by the shape of the potato,as different shape will have different surface are, meaning different rate of successful collisions and causing different rate of osmosis. Size of the solution: The smaller the molecules of the solution the faster rate of osmosis. Time: The longer osmosis goes on the slower the rate of osmosis as the concentration gradient decrease. Pressure: The pressure on one side of the membrane can increase or decrease the rate of osmosis by pushing the solution against the membrane. Light and dark: They are also factors of osmosis, since the brighter the light the faster osmosis takes place.
To create a fair test certain parts of the experiment will have to be kept same whilst one other key variable is changed. I have chosen to change the concentration of the external solution each time. This will give me a varied set of results. If any of the other variables were not kept the same then it would not be a fair test, for example if one of the potato chips was a different length to the rest this would affect the results and therefore would conclude in an unfair test. In my investigation I’m going to find out how effects a different concentration on the mass of a potato. I will be testing 6 different concentration starting from 0% water, 1%, 2%, 3%, 4%, 5% all the potato chips will be left for 24 hours in the solution. The mass of the potato chips will be measured before and after the experiment. And will be placed in a different type of solution 3 peaces of potato chips in different test tubes of the same solution to make my results more reliable. The change of salt concentration affects the osmosis pressure in the potato. The bigger concentration of salt in the water the more water the potato will reduce from it self so the water will balance what is called osmosis. Eventually the potato will shrink and become little but if the concentration is low inside the potato it will absorb water in it and become bigger.
The Coursework on Salt Solution Water Experiment Chips
... density of the potatoes were also difficult to measure accurately. The experiment should be repeated again using different concentrations of salt solution before accurate ... Experiment 1 Background Potatoes have selectively permeable membranes (cell membranes) that lets water move from cell to cell by osmosis Plan I am ...
Hypothesis:
Osmosis is defined as the net movement of water or any other solution’s molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with no area having a higher or lower concentration than any other.For this particular investigation I think that the lower the concentration of the salt solution in the test tube the larger the mass of the potato will be. This is because the water molecules pass from a high concentration, In the water itself, to a low concentration, In the potato chip.
Therefore, the chips in higher water concentrations will have a larger mass than in higher salt concentrations. The independent variables I have chosen to investigate is how different concentration of salt affects the mass of a potato. As the concentration of salt increases, the mass of potato decreases and as the concentration of salt decreases, the mass of the potato increases. This is because during osmosis, water diffuses from and area of high concentration to a low concentration. Aim: To investigate the effect of the change of concentration of salt solution on a sample of potato. The question that I will be investigating is whether the concentration of the salt solution affect the amount of water gained or lost by vegetables. Before starting my final experiment I will first do a series of preliminary experiments to help me prepare and make decisions regarding how I will go about completing the main experiment.
The Essay on Osmosis and Salt Concentration
... The highest salt concentration (15%) will have the most damaging effects on the potato cells. Due to the solution’s high solute concentration and low water concentration, water will ... Knife/ razor blade 6. Ruler 7. Distilled water 8. Salt concentrations (10%, 13%, 15%) Procedure for Osmosis Experiment 1. Separate the 20 cups into ...
Method:
Fist I’m planning to collect all the equipment needed for my experiment: 18 Test tubes
potato corer
3 potatoes
30cm ruler
salt solutions 0%, 1%, 2%, 3%, 4%, 5%
timer
1 board
1 pencil/ pen
2 sheets of paper
1 electronic weighing scale
3 different pen colors
Then I will construct a table to show my results. As shown on the next page. I will then carry out checks to make sure my result are accurate by making the experiment fair. I will collect all the equipment needed for this experiment. I am going to place a potato on a board. I am going to use a potato corer to core out a potato tissue. I will measure the size and cut it too 4cm. I will also weigh the potato pieces after they have been cut and record the data onto my table. Repeat this procedure seventeen more times to have eighteen potato tissues. I am cutting the potato 4cm using a knife. Then using my 6 different solutions 0% (water), 1%, 2%, 3%, 4%, 5% . After I’m going set up the beakers and the test tubes, I will place the potato chips inside the test-tubes and pure the different concentrations of salt solution into each of its own test tube. Repeat this step for each 3 concentration of the same solution’s. After I have poured the different concentrations of salt solution into each of its own test tube, I’m going to switch on the timer for the next 24 hours that I’m leaving the potato in the solution’s. After 24 hours I will take them out of the test tubes, and clean them gently with a paper towel. I am going to measure the weight of the potato chips, in their corresponding order. Then I will again collect this data on to the table I have planned.
The Essay on Soil Salinity Water Salt Irrigation
Soil Salinity Salinity in both the rivers and on the land is one of the main and most costly results of over clearing and irrigation. Salinity is caused by changes in the delicate balance between surface water and groundwater systems. A small increase in the infiltration of water from the topsoil to the groundwater, due to rainfall or irrigation, can result in a dramatic rise in groundwater ...
Method (containing) and result
I will then, pour the different concentration of salt solution into each test-tube and place a cored potato tissue and measure it and weight it using a ruler and a scale and record the data results on the table. I will leave it there for 24 hours. I will take out the potato tissues, weight it using a scale, and record the results on to the table. I will then compare the results on the table and then put or show the results on a graph I will plot the points above the osmotic if the trend or change is positive and vice-verse for negative ( under osmotic points).
Preliminary test:
I already know that osmosis is a process when a substance (usually solution) like salt or sugar dissolved in water, the solute attract some water molecules, and they cannot move around thus decreasing the concentration of water molecules. If there is a partially preamble membrane containing pure water, and that membrane is surrounded by solution with high water potential the water, the pure water would diffuse into the solution as the water molecules diffuse faster into pores of the membrane, as they are smaller than salt solution molecules. The salt solution will diffuse more slowly as they are bigger and take more time (thus less salt molecules diffusing) as the pores are not big enough. This osmosis (this is the same for vice-verse).
In my case, the potato tissues cell (semi-permeable) has cell sap (very dilute salt and chemical solution) inside its vacuole. It also has cell sap and reserved chemicals. The potato cell also has a cell walls that control torpor of the potato cell. If there is higher percentage of salt solution, which has a lower water potential, then osmosis will take place. This means that the water diffuses out of the vacuole into the salt solution and the vacuole gets smaller. Thus, the cell wall and cell membrane will collapse or shrink as there is no pressure being exerted on the membrane or the walls or there is less pressure. However, again using the osmosis theory. When there is high water potential in the salt solution outside than the vacuole inside the potato solution that the water molecules from the sugar solution will diffuse into the potato, and make it more turgid as there is more pressure being exerted on the cell membrane and cell wall as the vacuole will be bigger with more water molecules.
The Term Paper on The Solubility Curve Of Potassium Nitrate Experiment Report
The chemical compound potassium nitrate is a naturally occurring mineral source of nitrogen. It is a nitrate with chemical formula KNO3. Its common names include saltpetre (from Medieval Latin sal petrae: “stone salt” or possibly “Salt of Petra”), American English salt peter, Nitrate of potash and nitre. The name salt peter is also applied to sodium nitrate. Description: ...
This means that where osmosis has taken place and the salt solution has a higher water potential solution the potato tissue will be even shorter and lighter, as in the solution there will be less water molecules moving freely and these are the water molecules which diffuse thus meaning that there will be less water molecules diffusing into potato cell membrane. Moreover the water molecule in potato ( majority) will diffuse out make even less turgid. I know a potato cell will be or turgid when there is more water as vacuole and cell membrane can expend as it is confiding by cell wall so it exert pressure on it thus makes it more strong and turgid. Prediction:
I predict that if you increase the concentration of salt solution, you will decrease the mass of the potato chip. Using this background information, I can make firm prediction using the osmosis theory primarily. I think using different concentration I will get a varied result. The potato cell which has been in lower concentration of water will make the potato chops longer and more turgid. When potato chips is put in higher concentrations of salt solution, osmosis will take place and the potato chips will generally become more flabby, soft and flaccid. All concentrations will be measure in %, all liquids will be measured in (g) and length will be measured in (cm), temperature and degrees centigrade. Since the vacuole in the potato cell contain much more water the potato chip in general will be heavy if the sugar solution has lower concentration. However if the salt solution is higher that the potato chip then the potato chip will be lighter, as the potato cell will have loss mass trough losing water though osmosis.
Using preliminary work, which I have done will have improved my work greatly as in the past experiment using a potato chips I have used a smaller solution which was 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% which showed that there was not a big osmosis change. I changed the slat solution to a total number 0%(water), 1%, 2%, 3%, 4%, 5% that showed a better result in the final experiment I did. Also there for at my past experiment I left my potato chips in the solution only for 30 minutes which didn’t have much time to make any osmosis changes in the potato. Therefore at my final experiment I left the potato’s over night that had a better osmosis effect on the potato chip. Also my preliminary results may have been more inaccurate as only carried out the experiment once and in the final experiment I repeated it 3 times to improve its accuracy. In addition in that experiment I had also measured the variables for mass and this was more likely to produce anomalies as weight of extra water have got on the scale if the potato chips hadn’t been cleaned properly.
Full Risk assessment and fair test :
I am going to try to make my experiment fair as possible through many measures. To make my experiment fairer I will make sure, When I put the potato pieces inside the test tubes that they are all 4cm long. In addition, they are taken out of the test tube in the same order they went in. I will also label all the test tubes and clearly indicate what salt solution’s there are. Also, the same volume of 4cm of salt solution will go in each test tube regardless of salt concentration. I will wear goggles during the activity part of the experiment to protect my eyes. I will cut and core the potato on a board. I will be more careful not to cut anything or myself. I will put different test tubes containing the salt solution and the potato chip into beaker with water. This will help keep steady temperature through the experiment as water influenced environment will be less affected by sudden temperature changes. I will use the same size borer and pencil. When the experiment are done, I will place the potato chips on paper towel to absorb excess salt solution and then weight it.
The experiment will last then 24 hours, as I do not want any bacteria to spread or damage the semi-permeable membrane. I am taking these precautions to make my results more accurate as well. The potato chips always be 4 cm long before they go in and the same volume of salt solution will be used the concentration will vary. The experiment itself will be conducted on a normal mild day. I will also wear clear goggles to avoid the salt solution or any other utensils being exposed to our eyes. Safety was necessary in the experiment and I had to take a great deal of care. To ensure this, I did the experiment while standing in-case of any spillages that would occur. Using a cork borer and scalpel I had to take a great deal of care, as they both are very sharp items and could be harmful to those around me especially if I used them incorrectly. When using these two pieces of equipment I was very careful to make sure I did not cut any fellow pupils or myself. I was also aware when handling the glass test tubes, in case any spillages.
Graphs:The preliminary graph showed as the concentration increases the volume of the potato cylinders decreases, which clearly supports my prediction. The line is of best fit and is non – linear steady curve, the line slowly decreases and goes down and slowly rounds of. The graph shows there were no anomalous results. The first graph showed as the concentration increases the volume of the potato cylinders decreases, which clearly supports my prediction. The line is of best fit and is non – linear steady curve, the line slowly decreases and goes down and slowly rounds of. The graph shows there were no anomalous results. The second graph showed as the concentration increases the volume of the potato cylinders decreases, which clearly supports my prediction. The line is of best fit and is non – linear steady curve, the line slowly decreases and goes down and slowly rounds of. The graph shows there were no anomalous results.
Controlled variables:
Here are the possible variables that could have been investigated in this experiment. Concentrations
Surface area
Temperature
The chosen variable is concentration, because this is easy, efficient and can produce good results. The other two would be very hard to investigate and measure, so concentration will be investigated. The test will be a fair test because most of the factors that will be kept constant in the experiment. The following factors will be kept constant: Length of Potato cylinders.
Temperature- which is room temperature.
Apparatus s used for each experiment.
Total volume of solution.
The experiment room.
Source of salt solution.
Scale used to weigh the potato chips.
Potato
Light intensity
By keeping these things constant the experiment will be fair test, and will be able to give accurate answers. The experiment variables
Concentration of salt solution.
Mass of potato- only change in mass is needed so this does not matter. The concentration varies, as this is what we are testing. The mass varies as the mass cannot be kept constant, but this does not matter because only the change in the mass is needed. Evaluation:
The results I received were satisfactory and all supported my prediction that as concentration of salt solution increases, the volume of potato decreases – this is osmosis and when the potato cylinders are placed in water they increase in size -to form a turgid state. In an isotonic solution, there is little change. I feel I obtained satisfactory results I think if there was more time I could have investigated additional factors to broaden my investigation and perhaps even have more accurate results. Evaluation:
As could be seen the results I found were not entirely correct. Ideally I would like to repeat the experiment once more to ensure the results and conclusions I have made are correct.Another reason for the inaccuracy of results could be the fact that the apparatus used for both experiments were not the same. This was due to the fact that the second experiment was carried out after a few days, so the same experiment could not be used. This may be another possible reason why the results were not accurate the second time round.Different potato batches, and different salt solutions were used which may have caused some hindrance to the results. If these were kept the same for both experiments then the results would be better.The room temperature is similar. As temperature is a possible experiment variable that could have been done instead of concentration, it had to be kept constant. This is very hard to do, so the experiment was carried out at room temperature, but this could have changed between experiments or during experiments. If the temperature were kept constant then the experiment would be fairer and give better results.
This could have been done by doing the experiment in a temperature-controlled room, to ensure that the temperature remains constant.The experiment could also have given better results if I had used more accurate weighing scales, to give better weight readings.If I were to repeat the experiment I could have possibly found a machine to cut the potatoes. This would ensure that all potatoes would be the same weight and dimensions and make the experiment fairer and give better results.To find better results, I could also have measured the volume of the solution left when re weighing the potatoes. If this was done, then I could have seen if the volume changes match the mass changes. It would also have provided extra evidence for the accuracy of the results. In these ways I could have improved my current experiment I carried out.To extend my experiment I could test how concentration affects the rate of osmosis on different vegetables. I could have used different vegetables, like a cucumber.
Then I could find out whether osmosis occurs with the same trends with any vegetable.I could also have done the experiment with another solution instead of salt solution. I could have used sugar solution, and then compared the two sets of results to see if it makes a difference and why it makes a difference.I could also have extended this experiment by testing more solutions with the potato cylinders. I could have used more different concentrations of salt solution to give better results in this experiment. By doing this I could have found the isotonic point, which is where osmosis is balanced so there is water movement, as the water concentration is the same on both sides of the semi permeable membrane.I cold also have tested how the osmosis rate changes with different potato cylinder sizes. From this I would be able to see if the size of the potato affects the rate of osmosis.
