The graph shows that the first concentration 0.0M shows that the concentration was too much water than concentration. The 10.0M showed that there was too much molars in the concentration as it was all sucrose. However the graph shows that the concentration should be investigated between the ranges of 0.0M and 0.5M.
Fair test:
Apparatus:
Safety:
Diagram:
1. Use the core borer to cut out the potato cylinders
2. Cut the cylinders down to the size you want
3. Put the cylinders in boiling tubes from the strongest to he weakest solution
Method: First choose your potato, make sure it is big and new (big- so you can carve out many cylinders and new – so it can absorb the concentration well). Using the core borer, make sure your fingers are not in the way, push the core borer through the potato and carve out the number of cylinders needed. In my experiment, we carved out 15, because the experiment needed to be repeated.
The boiling tubes were then labelled with what the contents going to be in the boiling tube. 5 beakers, name the boiling tubes 1, 2, 3 and place in a beaker with a label saying what the solution is. The 1, 2, 3 is for the experiment which is being repeated.
In the first 3 tubes place 10cm3 of distilled water and 0cm3 of sucrose. The second beaker has 9.5cm3 of distilled water and 0.5cm3 of sucrose. The third beaker had 9.0cm3 of water and 1.0cm3 of Sucrose. The fourth beaker contained tubes, which has 8.5cm3 of water and 1.5cm3 of sucrose. The fifth beaker had 8.0cm of distilled water and 2.0cm3 of sucrose.
When the potato cylinders are carved out, cut them sown to size using a ruler and scalpel, quickly place them all in the boiling tubes so that they all start the experiment roughly the same time.
When the experiment had finished, we dried the potato cylinders and measure them with a ruler and record the results in a table. Below is the results table.
Results:
A graph showing the average potato lengths (using the table above)
This was our results table. The lengths were very close in lengthwise. We did not do the 0.5M as the concentration from the preliminary test showed an accurate length and we were finding out the accurate range of the concentration to find the isotonic solution. The isotonic solution was the 0.4M.
The graph below also shows the very reliable and accurate results. As it shows that the length by solution 0.0M was increased by 1mm and the 0.4M kept the length of the cylinder the same and 0.5M shortened the length by 1mm. The trends shows that the concentration was too low for the first 3 concentrations (as the length increased of the potato cylinder) and the 4th was the accurate and right one as the length of the cylinder was 3.0cm and the last concentration was too high in molars as the length decreased.
Referring back to the background information, this exactly what happened.
This is the more accurate graph showing the average lengths and what happened during the process, which increased or decreased to length of the potato.
Conclusion:
Evaluation: The procedure used worked which gave positive and reliable results. The procedure was like the method but was planned before the preliminary test.
The results seemed to be very accurate as they all have a decimal point and zero (in some cases). The results were quite very reliable as a conclusion could be made on the lengths of the potato cylinders.
The experiment could be improved on in many ways such as weighing the cylinders before the experiment and after to see whether the concentrate or the actual solution had an affect.
As well as using sucrose as the concentrate, sodium chloride could be something to compare the results with. Other experiments which could have been done if there was more time was changing the width / diameter of the cylinder, to see whether the diameter or width has a difference on the absorption of concentrate or the type of solution made up.
There were none anomalous results produced from the experiment. The other factors involved were not taken into consideration when the experiment was carried, but however those factors should and would have made a slight different as the light may make the cells absorb more of the solution or the heat of the room might of made the solution warmer during the day as the sun was shining and could of evaporated some of the solution. (These are some examples to why those other factors are important and how they should have been taken into account).
The good part of our experiment was that we chose a right range for our concentrations, which helped us find the right concentration amount.
Evaluating the fair test variables:
The outcome results were very accurate as they supported the prediction and what we were investigating, the concentration in potato cells (the one that is isotonic to the cell content).
There were no anomalous results surprisingly. Everything was neat and near accurate. This was good as the range was suitable and the trends were clearly shown.
Any further experiments that could support my prediction would be including the other factors that were could have been investigated apart from the concentration amounts. The other factors would be:
Other Factors Involved:-
¥ Temperature of the solution
¥ Light
¥ Mass of the potato cylinder
¥ Type of potato
¥ Surface area of the potato cylinder.
To investigate osmosis even further, we would need to include another factor to look at.
We could take the mass of the potato cylinder.
In order to do that, the cylinders would have to be cut out of the same potato, like before, it would also be cut down the same length. Using the same concentrations for this experiment , we would see whether osmosis would have an affect on the mass; seeing if the there was an effect we would look at the trends on a graph or in a table to see if the lengths have decreased or increased.
This could also link to the surface area of the potato cylinder, as the thickness of the cylinder may slow down the process of osmosis and a thinner piece of potato may help speed up the process.