• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigation On Osmosis

Extracts from this document...

Introduction

Investigation On Osmosis By Alex Rignall Investigation On Osmosis Aim To investigate how much change there is in the mass of a potato chip in varied concentrations of a sucrose solution. Prediction Osmosis: Osmosis is the movement of any of the 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 cell membrane or a partially permeable membrane, which lets small molecules through and does not let large ones through. I predict that the lower the concentration of sucrose in the solution the more the potato chips will expand. I can say this because I know that there will be more water molecules and therefore osmosis will take place between a lower concentration of water molecules and a higher concentration of water molecules that are separated by a partially permeable membrane such as a the cell membrane of the potato. The sucrose will not cross the partially permeable membrane because the molecules are too big to fit in between the gaps in the membrane. The higher the concentration of sucrose in the solution the more the chips will decrease in mass. I can predict this because from my previous prediction I know that the potato chip will have a higher concentration of water molecules, and therefore the water molecules in the potato chips will move across the partially permeable membrane (the cell membrane) ...read more.

Middle

We could not use the same potato for all the chips because it was not big enough and we also could not ensure that the next potato was similar. We could however make sure the potatoes cam from the same place and this would therefore help make the experiment fair. We tried to control the temperature as best we could but there is no way we can make it exact and constant in such a large room, so the rate of the osmosis may have been affected by temperature. We did try and minimize all the above by leaving the petri dishes out for over 24 hours. Results I collected results from the first experiment and recorded them in the table below. I then worked out the percentage change of the potato chips. (Percentage change = Difference between before and after/Original) Solution Weight before Weight after % Change experiment (g) experiment (g) 0 molar 3.34 4.105 23 .25 molar 3.43 3.52 2.60 .50 molar 3.37 2.825 -15 .75 molar 3.31 2.39 -28 1 molar 3.43 2.21 -36 When I repeated the experiment in recorded the results in a graph like the one above and again worked out the percentage change. Solution Weight before Weight after % Change experiment (g) experiment (g) 0 molar 3.11 1.975 14.4 .25 molar 3.26 3.24 -0.6 .50 molar 3.24 2.64 -18.5 .75 molar 3.11 1.975 -36.5 1 molar 3.36 2.32 -31.0 In order to make it a fair ...read more.

Conclusion

The other variable that was hard to control was the amount of solution in each petri dish. We wanted 50ml in each one but by using a measuring cylinder some may have been left inside a not gone into the petri dish. To make it more accurate next time I would use a burette. There where no results that where completely off the line but there is one that I would like to discuss. I tried to rule out abnormal results by taking an average of them all but it seems that I should have repeated the experiment more to rule out this abnormal result. It is the result for .75 molar that is the odd one out, it measured at a 32.25% loss but the best fit line shows it should have been about a 29% loss. This result on the best fit line would have been closer to the first result telling me that my two chips taken for 0.75 molar where from a bad part of the potato. This result rules out the possibility that the first experiment chips where dried too much with the paper towel because if it was then the best fit result would have been closer to my second experiment result. I admit that some of the chips may have been dried too much but not as much to change the result by 7%. However even with this result I am satisfied that my experiment was very successful and that my results are accurate enough to have been analyzed. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Exchange, Transport & Reproduction section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Mr Chips: Investigation to find an isotonic solution for potatoes

    4 star(s)

    4.75 3.45 -1.30 -27.4 The results from this test show that only the zero percentage concentration caused the potato to draw water in through osmosis, the amount was also very low allowing for the presumption that these particular potatoes did not contain a high level of sugar therefore have a low level water potential within their cells.

  2. Marked by a teacher

    Osmosis. Aim: To find the molarity of potato tubers cell sap. BIOLOGICAL ...

    4 star(s)

    This will result in inaccuracy. This can be done be cutting the potato strips using a cork borer to get a smooth surface and then resizing it to a similar length. This will result the potatoes to have the same surface area.

  1. Marked by a teacher

    This is an experiment to find out what factors affect osmosis in potato chips.

    3 star(s)

    All measurements will be using the unit mol dm-3 . Prediction In my experiment my prediction is that the lower the concentration of the sucrose solution the higher the amount of increased mass of potato chip. I think that the mass will increase because of the process of osmosis.

  2. Investigation on Osmosis using a potato.

    * Measure temperature of the water before the experiment so that it will make it a fair test without any change in temperature. * Make a larger range in readings so it will be easier to compare results and it will be easier to draw a line of best fit as well as comparing the results to the prediction/hypothesis.

  1. An investigation to demonstrate osmosis using a potato

    sharp knife which I will be using to cut the potatoes with. I will make sure that I have an overall so that my clothes don't get dirty if the solutions spills. I will remember not to put potatoes or sucrose in my mouth as they might have been infected by chemicals in the lab, which are poisonous.

  2. Investigating Water Potential Of Potatoes.

    flow in either direction and the external solution is said to be isotonic with the cell. The osmotic flow of water into a cell is called endomosis, and the flow out of it is called exomosis (mastering biology, OFG Kilgour, Pg.

  1. Investigating osmosis on swede cells.

    3 chips will be needed per concentration; so 18 chips shall be needed in total. This will allow room for anomalous results so an average of the three results can be taken to be analysed. 3. Pat the swede chips with a paper towel to remove any excess moisture so that the mass reading is true and accurate.

  2. Fundamental human anatomy and physiology.

    Reference: http://training.seer.cancer.gov/module_anatomy/unit9_4_resp_passages.html Class notes hand out 26 / 2/ 2008 Web sight viewed on 27 / 2 /2008 * The respiratory system consist of the nose, mouth, throat, larynx, trachea, bronchi and lungs, therefore the function of the respiratory system is to help gaseous exchange to take place in the lungs and tissue cells of the body.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work