An investigation into the osmosis of potato cells.
What affect does concentration of solution have on potato tissue?
In my preliminary investigation, I will be controlling the following variables:
- length of potato cylinder;
- amount of solution / water;
- type of potato;
- size of potato;
- temperature of water;
- same ruler / person.
Changing the concentration of solution:
Using three glass test tubes, I will set up the following configuration:
- Test tube 1 – Distilled water;
- Test tube 2 – 5% salt solution;
- Test tube 3 – 10% salt solution.
All quantities will be made the same and accurately measured to ensure a fair test.
I will accurately cut three pieces of potato chip (40mm / 4cm), each one the same length. Each chip will then be inserted into each test tube simultaneously. I will then leave them in the test-tube for twenty minutes, take each out simultaneously and then record the difference in length for each chip.
After conducting my preliminary experiment, I have recorded the following results:
To improve the reliability / accuracy of my preliminary investigation, I could make the following changes:
- not using the same cylinder to measure out the different water solutions;
- calculating the mass change in the potato chip, by measuring both length and width of the potato chip;
- calculating a value.
I am investigating what effect changing the external concentration of a solution has on potato tissue. I have carried out a preliminary result and will now repeat the experiment with an improved method after reviewing the flaws discovered in my preliminary experiment.
There are several variables I can control in order to get a different outcome to my experiment:
- temperature of the atmosphere in which the investigation takes place;
- surface on which the investigation takes place;
- length of time in which the chip is submerged in the solution;
- position of potato chip;
- size of potato chip;
- amount of solution;
- concentration of solution.
I will change the concentration of the solution in more regular intervals compared to that of the preliminary experiment – 0%, 2%, 4%, 6%, 8% and 10%. Last time, I carried out the experiment varying intervals of 0%, 5% and 10% salt concentration. Decreasing this range will result in more accurate results, with more to analyse and therefore enable me to gather a greater idea of what is going on in this investigation. I will control the temperature of the atmosphere in which I conduct my investigation by carrying it out in the same location each time. I will control the surface I am working on and keep the chip size consistent by accurately cutting the chip. I will try to ensure that the position of the chip within the solution remains consistent so that my investigation is accurate and gets the best results possible.