Due to the reasoning above I will use 0.3, 0.4, 0.5, 0.6, 0.7 these new concentrations will enable me to find the precise isotonic point.
When the root vegetable is placed in the 0.3 molar sucrose solution I will expect the root vegetable to become turgid, because at this concentration the root vegetable will have a higher water potential and a lower solute potential. Therefore the water molecules will enter the root vegetable at this concentration by osmosis and will create a pressure potential.
Water potential equation
This pressure potential will cause the protoplast in the cell and this will be pushed against the cell wall. This will cause the root vegetable will become turgid as it mass/ width and length should increase. I predict that at 0.3M a hypotonic solution will exist as this solution will have a higher water potential than the root vegetable cylinder.
As I know that water potential = pressure potential + solute potential. In a hypertonic solution the water potential in the solution will be greater than that in the root vegetable therefore water will enter the root vegetable cell and will increase pressure potential of the cell will and this in turn will cause the water potential to increase. The above equation clearly states that increased pressure potential increases the water potential because Water potential= pressure potential + solute potential. At this concentration I expect the masses of the root vegetable to increase.
Alternatively if the solution has a higher concentration than the root vegetable then by process known as osmosis; the water in the root vegetable will leave the root vegetable and enter the high concentration solution. Therefore the root vegetable will become flaccid and the root vegetables mass will decrease.
The diagram above shows that before osmosis occurs, the two solutions are separated by a partially permeable membrane. As the sugar solution has a higher concentration than the solution inside the partially permeable membrane the water molecules move from a region of high water potential to low water potential, therefore the water in the low solute concentration on the right will move to the high solute concentration on the left. As a greater net movement of water will occur out of the diluted sugar solution the cell will become flaccid. This can be directly linked to my investigation, if I place a root vegetable cylinder into a solution with a higher solute concentration, the outer layer of my root vegetable will act as the partially permeable membrane, only allowing water molecules to move into and out of it.
This is why I predict that in the 0.7 molar concentration of sucrose solution I expect the root vegetable to become flaccid because this solution is a hypertonic solution. Therefore this solution has a higher solute potential that the water potential present in the solution. Therefore I predict that the water in the root vegetable cylinder will leave the cell by osmosis and this will make the root vegetable cylinder flaccid, because the protoplast will shrink until its exerting no pressure on the cell wall because most of the water present in the protoplast of the root vegetable cell will leave it and enter the low water potential in the solution. At this point the pressure potential is zero. Therefore the root vegetable cell starts to become plasmolysed as the protoplast begins to move away from the cell wall, this can be seen in the 4 picture of the plant cell to the right.
Due to this I predict that when the root vegetable is placed in a hypertonic, where the concentration of the solute in the solution is greater than the solute potential present in the root vegetable, the mass/ width and length of the root vegetable will decrease.
I also predict that the isotonic point for each root vegetable should occur at 0.5 molar sucrose solution because at this concentration the water potential and solute potential are equal in the solution. At this concentration the net movement of water molecules into the root vegetable cylinder should equal those that will leave the root vegetable cylinder.
The diagram above shows that equal amount of water molecules are entering and leaving the partially permeable membrane. This is because at this concentration the water molecules and solute molecules are present in the solution in the same proportion. Therefore the net movement of these molecules should be equal resulting in no change. Therefore I predict that at the 0.5M solution the isotonic point should be obtained.
At the isotonic point the plant cell becomes flaccid as it is shown below. Therefore I can say that the mass affects the isotonic point because when the mass doesn’t change the net movement of water in the cell will be equal. When the mass is increased it is placed in a hypotonic solution and when decreased it is placed in a hypertonic solution. Although at the isotonic point the cell becomes flaccid but the mass will be unchanged at this point because the net movement of water will be equal. I also predict that as the cell becomes flaccid in the isotonic solution, the pressure potential exerted will become zero and due to slight fluctuations in pressure potential the length may be affected. This is why I predict that at the isotonic point the mass will be unaffected but the length will be slightly affected as I predict that the pressure potential applied will be below zero.
This is why I can conclude in saying that the isotonic point should lie between 0.3- 0.4 for each root vegetable as my preliminary work showed me that at the 0.5-0.6M concentrations. The net movement of water was greater out of the cell than into to it. This showed me that the root vegetable cylinder was placed in a hypertonic solution. Due to this the isotonic solution would be less concentrated, as this would me that less water is leaving the root vegetable. By using this theory I can therefore conclude by saying that I expect the isotonic point for each of my root vegetables to exist in the 0.3-0.4M solution.
FAIR TEST
To keep experiment fair, only one variable can be changed. The variable that will be changed will be the four different vegetables. All the other variables must be kept the same such as:
- Use two different pipettes one for water and one for sucrose this will avoid cross contamination of the two solutions because if the sucrose pipette is used for measuring water then the water will no longer be pure hence the reliability and accuracy of my results will be affected. Then the diluted solution made will be affected as they will either become more concentrated or more dilute. As inaccurate solutions will be made my results will be affected. This is why it is crucial that I use two different pipettes.
- To make sure that I have a fair test I can only have one variable in this experiment and this will be the root vegetables as 4 different types will be used the concentrations of the sucrose solution will be kept the same for each root vegetable.
- Label the beakers of water and sucrose to ensure to confusion occurs in identifying which solution is sucrose or water.
- Leave all the McCartney bottles with the root vegetable cylinders for 24 hours, as this will make sure that each root vegetable has been left in the solution for the same amount of time.
- The root vegetable cylinder should be taken from the same four original root vegetables, if another root vegetable is used it may have a different solute potential hence it will have a different isotonic point. This is why it is important to use the same root vegetable. This is important because by using a different root vegetable cylinder for the same root vegetable the water content in the root vegetable cylinder will be different as its solute potential will be different. Due to this a different root vegetable will have a different isotonic point and therefore my results will have a low level of precision and reliability. This is why it is important to use the same root vegetable for each concentration as this will keep my results constant.
- Use the same sized core borer because a different size will mean that the root vegetable will have a different diameter hence the results can be affected. This will ensure that each root vegetable has the same surface area to volume ratio; therefore the surface area will be kept constant in my experiment resulting in it not being a factor which can affect my results.
- Use the same electronic balance as it will have the same amount of accuracy and percentage error hence this will make my results more reliable.
- Same amount of volume for each solution should be added to each root vegetable because if more of one is added then the results will be affected. This will be done by using two of the same pieces of equipment. In my practical two of the same 10ml glassed pipettes will be used, therefore as all equipment has a percentage error, the error of measurement for the pipettes for each solution added for each concentration will be kept constant.
- All the root vegetable must be cut to the same length and by the same person as people show variation in their eye sight if one person cuts the length of the root vegetable the results will be more accurate as the lengths will be constant. By cutting those to the same length the surface area to volume ratio of these root vegetable cylinders will be kept constant.
SAFETY
- Clean any spillages immediately, keep the paper towels close by so you don’t have to move around the room reducing chance of collision in the class.
- Wear your safety spectacles to prevent any chemical or solution entering your eye.
- Use the equipment sensibly and appropriately as some equipment is made of glass and break easily so place it around a place where the chance of fall is minimal.
- You must be careful with the glass ware as it can be a safety hazard if the glass the glass is broken. Therefore ask for assistance from your supervisor.
- The scalpel used are extremely sharp and can cause cuts if not used safely therefore when using this piece of equipment use it with a high level of care.
- The electrical appliance used in this experiment will the electronic balance make sure you don’t place water near the socket for the plug as this can cause the risk of being electrocuted. Make sure your hands are dry when placing or removing the plug from the socket. If your hands are wet you will be at risk of being electrocuted.
The method of dilution of the 1molar sucrose solution.
- Collect the appropriate equipment required.
- Label the 5 of the 20 McCartney bottles as carrot and one of the concentrations of 0.3, 0.4, 0.5, 0.6, and 0.7.
- Repeat this process for each root vegetable and label each McCartney bottle with each concentration and the name of the root vegetable.
- Then remove the McCartney bottle lids and place them on the side.
- Using the sucrose pipette measure 6ml of sucrose and add it to the 0.30 molar sucrose labelled McCartney bottle with Parsnip, using the water pipette measure 14ml of water add to the same McCartney bottle.
- Using the information in the table add the correct amount of the 1 molar sucrose solution and water to the appropriate beaker. Repeat this process for each concentration until the required concentrations are made.
Method for actual experiment
- Using a core Borer sized 4 you cut out five cylinders of each of the four different root vegetables and then place all the carrot cylinders on the paper towel and all the potato cylinders on a separate paper towel and all the parsnip cylinders on a separate paper towel and finally place all the Swede cylinders on a separate paper towel.
- Each time a vegetable cylinder is cut using a size 4 core borer use a small core borer to remove the root vegetable cylinder from the core borer.
- Using a scalpel you cut the all the root vegetable cylinders to length of 30-millimetres.
- Using a ruler measure the length of each of the root vegetables and record results in your appropriate results table.
- Remove any peel from the root vegetable cylinders as this can affect osmosis by acting as a barrier.
- Start by cutting all of one of the root vegetables then clean the scalpel safely and remove any stains from previous root vegetables.
- Then measure the mass of each root vegetable cylinder used by using the electronic balance. Then record the mass of the root vegetable to the appropriate results table. Do this for every root vegetable and place the correct root vegetable cylinder to the appropriate McCartney bottle.
- Firstly do this for the carrot root vegetable and place it in the solutions before starting the other root vegetables.
- Then place the root vegetable to the appropriate labelled McCartney bottle. Leave your bottles for approximately 24 hours.
- Then repeat process 1-9 for each of the remaining 3 root vegetables which are Swede, Parsnip and Potato.
- Once the 24 hour time period has finished pour all the sucrose solutions into the sink.
- Remove each root vegetable cylinder in turn and slightly dry with a paper towel. Then using a ruler measure the end length of each root vegetable and record these results in the appropriate part of your results table. Then measure the mass of each root vegetable and again record the results to the appropriate part of your root vegetable.
- Repeat this process until you have measured the end mass, length and width of each root vegetable cylinder and have filled in all your results tables.
Equations required calculating the percentage increase/ decrease in the mass, length and width of each root vegetable.
Mass= End mass- start mass ÷ start mass x 100
Length= End length- start length ÷ start length x 100
DIAGRAM FOR FINAL EXPERIMENT
Results
Swede
Mass of Swede cylinder
Length of Swede cylinder
Parsnip
Mass of parsnip cylinder
Length of Parsnip vegetable cylinder
Potato
Mass of Potato vegetable cylinder
Length of potato cylinder
Carrot
Mass of carrot cylinder
Length of carrot vegetable cylinder
ANALYSIS
The pattern my results and graph have shown are that the higher the concentration of the sucrose solution the more likely it is that the root vegetable cylinders mass will decrease as all my line of best fit show a negative correlation, this means that as the concentration increases the percentage change in decreased mass decreases. Therefore its overall % change will be lower than the root vegetable placed in a lower concentration.
In my prediction I stated that at a lower concentration a higher water potential would exist in the sucrose solution therefore by mean of osmosis water will move from a region of high concentration in the root vegetable to a region of a low concentration in the sucrose solution through a partially permeable membrane and due to this the amount of water in the root vegetable cylinder will decrease resulting in a decrease in the mass of the root vegetable cylinder.
From my results for the potato root vegetable I have found that the potato placed in the sucrose solution of 0.2 and 0.25 became turgid as it mass, length and width increased. This occurred because a higher water potential was present in the sucrose solution than in the potato cylinder. Therefore the water molecules in the sucrose moved from a region of high water potential to a region of lower water potential through a partially permeable membrane into the potato cylinder. As this causes the living internal part of the potato cell known as the protoplast to be pushed against the cell wall to create turgor pressure. At this state the potato cell was said to be turgid.
However the % increase in mass, length and width of the potato cylinder occurred at a higher proportion with the 0.2M sucrose solution, this is because 0.2M sucrose solution has a higher water potential than 0.25M sucrose solution as less sucrose molecules are present in the solution. Therefore the tendency of water to move by osmosis occurs more rapidly resulting in the potato cylinder placed in the 0.2M sucrose solution to have a greater proportional increase in mass, width and length.
The potato cylinders placed in the sucrose solution within the range of 0.3-0.4 should also have had an increase in mass, width and length, but this was not the case `as the mass the width and the length actually decreased for the potato cylinder placed in these concentrations. This therefore means that water molecules actually moved out of the potato cylinder and into the sucrose solution.
This is the case as the molarity of the sucrose solution increases the tendency of water to move out of the root vegetable also increases in order to create equilibrium and enable me to find the point at which incipient plasmolysis exists(equilibrium in osmosis).
The carrot cylinder was placed sucrose solutions with molarity of 0.4, 0.45, 0.5, 0.55 and 0.6. The trend I spotted with the carrot cylinder was that it’s mass, width and length increased in the 0.4 and 0.45 molar sucrose solutions. This is because a higher water potential is present in these solutions and hence the rate of water movement into the cell was greater. In the 0.5 M sucrose solution the width and mass increased but the length decreased.
This was quite surprising as you would expect the incipient plasmolysis to occur at this stage where the % presence of water and sucrose levels is equal. This may have occurred due to factors out of my control and will be considered in more depth in my evaluation.
When the carrot was placed in the sucrose solution with molarity of 0.55 -0.6, the mass, width and the length of the carrot cylinder actually decreased. This occurred because a higher water potential existed in the carrot than was present in the sucrose solution with these molarities. Therefore it caused the water to move out of the carrot cylinder by osmosis into the sucrose solution. This also causes the protoplast in the cell of the carrot to move away from the cell wall, hence it is said that the carrot has become flaccid. Any water present in the vacuole is also lost from the cell and the diameter of the vacuole decreases. Due to the reasoning above the mass, width and length of the carrot cylinder decreased at the molarity of 0.55 and 0.6.
The carrot cylinder became flaccid at the molarity of 0.55M because a hypertonic solution was present, this means that a higher solute potential existed in this solution than in the carrot cylinder. This means that the water molecules left the carrot cell at a higher proportion than the entering it.
Therefore this caused the water molecules from the carrot cylinder to move to a region of low water potential by the process of osmosis. Therefore as the water moved out of the carrot cylinder at this concentration it caused the mass to decrease with the diameter and length also decreasing. The length and diameter of the carrot decreased because the living material in the carrot cell known as the protoplast moved away from the cell wall. This therefore caused cell wall to go inwards as the pressure required to push it outwards is no longer present. This is what caused the carrot cell to decrease in length and width at this concentration.
The beetroot was placed in sucrose solutions with molarity of 0.6, 0.65, 0.7, 0.75 and 0.8. The beetroot placed in sucrose solution with molarity of 0.6 and 0.65 had an increase in mass, width and length as these results indicate to me that the beetroot had a higher solute potential than the sucrose solution with this molarity and hence this caused the beetroot to experience turgor pressure.
This therefore showed me that when the beetroot was placed in the solution with a molarity of 0.6 and 0.65, that a hypotonic solution was present. This solution had a higher water potential than the beetroot therefore more water flowed into the beetroot cell than flowed out.
The beetroot had a lower water potential than the water potential present in the solution, therefore the water in the solution moved from a region of high water potential to a region of low water potential through the partially permeable membrane of the beetroot cylinder. This water entered the vacuole of the beetroot cell because in the vacuole a high proportion of solutes are present and this caused the vacuole to expand. Also the water entered the living material of the cell known as the protoplast. This therefore caused the protoplast to push against the cell wall by creating a pressure potential.
Due to this the beetroot cylinder placed in the 0.65 and 0.6 molar solutions was said to be turgid. The mass increased because a higher proportion of water was present in the cell.
The width and length increased because the pressure created by the inflow of water caused the protoplast to push against the cell wall. This therefore caused the cell wall the slightly expand by a small proportion showing an increase in the length and width of the beetroot cylinder.
But in the 0.7m sucrose solution the mass increased but the length and width decreased although the mass increase was less than a %, but this indicates to me that incipient plasmolysis for the beetroot lies in between this region or that other external factors may have affected my results by creating an anomalous result which will be discussed later in my evaluation.
For the 0.75 and 0.8 molar sucrose solution the mass, width and length all decreased for the Beetroot. This means at these two concentration of sucrose solution the solute potential was greater in the sucrose solution than it was in the Beetroot cylinder hence, this means that a higher water potential was present in the beetroot than was present in the sucrose solution by osmosis water is lost form the beetroot causing it to become flaccid.
Finally the fourth root vegetable used was the parsnip it was place in sucrose solutions with molarity of 0.80, 0.85, 0.9, 0.95and 1.0. When it was placed in the 0.8M concentration the mass, width and the length of the parsnip increased and this indicates to me that a higher water potential was present in the sucrose solution that it was in the parsnip. When the parsnip was placed in the 0.85M concentration its width didn’t change but the length of the parsnip cylinder decreased and the mass also decreased. This was a pattern that continued in the 0.9, 0.95 and 1.0 molar sucrose solutions. By analysing these results it shows me that the point of incipient plasmolysis for the parsnip lies between 0.8 and 0.85 molar sucrose solution.
From the evidence obtained I can now further narrow my range for the point of incipient plasmolysis for each root vegetable. From my results I have calculated the percentage increase and decrease in mass/width/length of each root vegetable. I have used these values to plot 4 graphs.
As I was measuring the change in mass/ width and length I cannot get a precise point of incipient plasmolysis, but the lines of best fit for each root vegetable have the same range in which the mass and width are covered.
Therefore to work out the precise point of incipient plasmolysis I will work out the area covered in the range and divide it by 2 and then add this value the first value of the range. This value will give me the point of incipient plasmolysis for each root vegetable.
The point of incipient plasmolysis for each root vegetable cylinder was found once the isotonic point was obtained. I obtained this value when the line of best fit intersected the x- axis which was the concentration value. From this I obtained the isotonic point. The isotonic point is the point where incipient plasmolysis exists. What I found at this point was that there was no change in the mass/width and length. This was the case because the proportion of water coming into the root vegetable cell was equal to that leaving the cell. Hence it could be said that equilibrium exists at this point as their was no change in the mass/ width and length of each root vegetable.
The point at which these graphs intersect the x-axis is the point where the percentage increase is 0 and hence this will be the point of incipient plasmolysis.
For the potato the point of incipient plasmolysis exist in the region between 0.25 and 0.3 molar sucrose solution. The potato has point of incipient plasmolysis at 0.258.
For the carrot the point of incipient plasmolysis lies between 0.45 and 0.55molar sucrose solution. The carrot will have a point of incipient plasmolysis at 0.492.
For the beetroot the point of incipient plasmolysis lies between 0.66 and 0.71 molar sucrose solution. Beetroot has a point of incipient plasmolysis at 0.683.
The parsnip has a point of incipient plasmolysis that lies between 0.82 and 0.83 molar sucrose solution. The parsnip has a point of incipient plasmolysis at 0.832.
.
EVALUATION
Overall the results that I have obtained seem to be viable as they all seem to show a negative correlation that as the concentration increases the percentage change decreases.
Due to this the general trends suggest to me that this experiment was conducted well and fairly accurately as I have obtained a good set of results. The experiment was relatively suitable for this practical as I obtained results which generally agreed with my hypothesis. Therefore I can say that this procedure for my experiment was suitable.
Once I obtained the results from this experiment I obtained percentage values and plotted them on my graph some results didn’t fit the general pattern I identified and due to this these results are recognised as anomalous results and they have been circled and identified on my graphs.
Anomalous results
The anomalous result for the potato cylinder was the % change in width the actual % change obtained was -1.11%, but it should have been in the region of -2.6%. When the potato cylinder was placed in the 0.3M solution the change in width was -1.1%, as the concentration increases the width change should also decrease by a greater proportion. The factors why this may have occurred will be discussed later.
The values above are my anomalous results and they have occurred due to errors which occurred during my practical. The errors which occurred to affect my results resulting in me obtaining anomalous results only affected individual results these errors include human errors and equipment errors.
As I only obtained a small proportion of anomalous results I can therefore say that these anomalies in my results occurred due to the errors named above.
I may have measured an inaccurate volume of water because of human error of judgement therefore I may have added less water resulting in the sucrose solution being more concentrated than I expected and due to this the decreases in the mass width and length which I have identified as anomalous results show me that the cell became flaccid and this occurred because the solution was more concentrated with sucrose than it was supposed to be and this is a human error as I wrongly measured the volume of water. Consequently, resulting in me obtaining anomalous results.
Another human error which may have occurred was during the measurements of the mass width and length. When measuring the mass I obtained the masses by placing the root vegetable cylinder on the 2 decimal placed electronic balance, but when measuring the mass I obtained a value, as distraction exist in the surrounding environment where this practical took place I may have been distracted and recorded the incorrect mass and to reduce the chance of this error happening again it is crucial that I am not distracted and make sure I check the mass twice before recording it. Due to this I may have gained anomalous results for the masses obtained. Or when measuring the mass of the root vegetable I may not have set it to 0.00grams. Therefore I obtained an inaccurate mass. When measuring the mass I will ensure that next time I set the balance to 0.00grams. This will make sure that only the mass of the root vegetable is measured and that no other substances mass is included in the mass of the root vegetable. This improvement will improve the reliability of my results because a more accurate mass will be obtained for the root vegetable which in turn will allow me to calculate a more accurate percentage change in mass for the root vegetable.
The judgement of the human eye may have caused my anomalies in my result when measuring the length and width of these root vegetable cylinders, I used a 30milimetre ruler. Due to distractions I may have used a similar 30 millimetre ruler but not the same ruler this therefore means my, that my results are not constant because a ruler is a piece of equipment in terms of error each different time of ruler has its own proportional error; therefore I obtained anomalies in my results. The improve my results I will use the same ruler the measure each root vegetable as this will make sure that each root vegetable has the same experimental error making my results constant and more reliable.
Also when measuring the length I may have thought that the length was 32milimetres but actually it was 31milimetres and due to the error of judgement from the human eye I obtained anomalies in the length and width for my results. To reduce this chance of error and improve the accuracy and precision of my results next time I will concentrate more and spend more time when taking the measurements as this should reduce the chance of error in my results. This in turn should increase the accuracy and precision of my results.
Another error which may have occurred was that when placing the lids back on the McCartney bottles, I may not have placed the lids properly on some of the bottles and this may have caused evaporation to occur resulting in some solution becoming more concentrated. Therefore the anomalies which I obtained with decreased mass/ width and length may have occurred due to the reasoning above. Therefore next time I will ensure that all the McCartney bottles have their lids tightly placed on them as this will minimize the risk of evaporation. This will result in me obtaining results with high amount of accuracy and precision.
The significant sources of error affected the accuracy and precision of my results these factors are discussed below.
These limitations include equipment errors present on the equipment, the 10ml pipettes used for the dilution of 1 molar sucrose solution have a percentage error of (+-) 0.1ml, therefore when adding water to the 1molar stock solution more or less water may have been added and therefore this dilation of the 1 molar sucrose solution may have created solutions with different molarities to those that I have recorded. As incorrect molarities it meant that the root vegetable cylinders were placed in a solution which was either more dilute than expected or more concentrated with sucrose molecules than expected and therefore this may have caused the mass/ width or length to either increase or decrease by a greater proportion than I expected, therefore this could be one of the limitations resulting in me obtaining anomalous results. A way to improve the reliability and precision of my results I will use more accurate equipment hence pipette with a lower percentage error as this will mean a more accurate concentration of each solution will be made and this will mean that the solutions are not more concentrated or more diluted. As an accurate molarity of the solution will be made the isotonic point obtained from my results will be more reliable.
The above comments will make my results more accurate because a lower proportional chance will exist of me making an error when making the different concentrations. Therefore the chance of me making more accurate concentration of sucrose will increase with more accurate equipment, which in turn will mean that I will obtain more accurate results.
Also before I started the experiment I rinsed out all the equipment with distilled water to deionise the equipment to ensure that my solutions made by the dilation of 1 molar are not cross contaminated, but as this removes any ions it doesn’t remove any living material.
Therefore if the enzyme sucrolase was present in the pipettes or the McCartney bottles, then this enzyme would break down the sucrose into glucose and fructose and therefore the molarity of the solution would be slightly different as glucose and fructose are present rather than sucrose.
Due to this it will result in different concentrations of solute present in the solution which will affect my results as different concentrations will be made. Alternatively as most living organisms have an optimum temperature below 40 degrees Celsius by rinsing the equipment at this temperature with distilled water will destroy any living organism and will reduce and minimise the chance of my results being affected. This will therefore increase the accuracy and precision of my results because it will remove any living content in the equipment used and therefore it the enzyme sucrolase was present it would be destroyed which in turn would mean that the sucrose is not broken down. Therefore the molarity of the solution will not be affected. Due to this a more accurate molarity for the solutions will be made resulting in me obtaining results of increased accuracy.
When the length of the root vegetable was measured with a ruler it was measure in millimetres, but when I had carried out the practical I had to measure the length again but the length of the root vegetable cylinder came in between a millimetre therefore I had to estimate the value for the length, as this error occurred due to a poor piece of equipment.
To improve the accuracy and precision of my results instead of using a ruler I will use a micrometer as this piece of equipment will improve the accuracy of my results and would also contribute to the reduction of the inaccuracy of the human eye, because the micrometer is a specialised piece of equipment which measures the length of substances. By using the micrometer a more accurate length and width of the root vegetable cylinder will be obtained. As a more accurate result is obtained by using the micrometer then in terms of justification this will improve my results and this justifies why this piece of equipment should be used because by using this piece of equipment the accuracy and precision of my results will increase.
Once the practical was complete I was suppose to dry the root vegetable cylinder to remove the water and then I measure the mass of it. Also the weighing of the root vegetable will not be as accurate due to poor drying of the root vegetable. Therefore the mass that I recorded may still have had some water present due to poor drying and therefore the mass I recorded will be inaccurate. To obtain a more accurate mass and ensure that no water is present on the root vegetable cylinder I will use a hair dryer for 2 minutes for drying each root vegetable. By using the hair dryer for the same time period will ensure that the same amount of water is removed from each root vegetable cylinder and therefore a more constant mass will be obtained for each root vegetable. This in turn will make my results more accurate because by using a paper towel for drying different amount of water will be removed by using a hair dryer at the same level for the same time will ensure that a more accurate end mass is obtained this will therefore improve the accuracy of my results.
To obtain a more accurate mass I will use a electronic balance which goes to 3 decimal places, the one which I used for my actual practical went to 2 decimal places, due to this I may obtained an inappropriate mass resulting in me obtaining a few inconsistent results. Therefore by using a 3 decimal place electronic balance a more accurate mass will be obtained, which will therefore increase the reliability and precision of my results because a more accurate end mass will be obtained.
Even with the anomalous results I can accept the validity of my results because although factors may have occurred which were out of my control, but the results I obtained show the trends and patterns that I expect although there are a few exceptions in my results in the term that anomalous results exist. By examining my results and the procedure used to carry those out I accept the validity of my results as the procedures experimental errors that occurred were out of my control. Overall my results are correct and the few anomalous results do not affect the validity of them.
Bibliography
#http://schools.moe.edu.sg/chijsjc/Biology/Diffusion&osmosis/osmosis.gif
o the cell, so therefore equilibrium has been reached.
Essential AS Biology for OCR- Glenn and Susan Toole
Biology 1- Cambridge Advanced Sciences-
Authors- Mary Jones, Richard Fosbery, Dennis Taylor
Centre number 20603 candidate number 1216 name – Mohammed Zafran