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

Investigate the factors affecting the rate of Osmosis.

Extracts from this document...

Introduction

Planning Osmosis is the diffusion of water from a lower concentration of solute to a higher concentration of solute, through a partially permeable membrane. In a high concentration of water the amount of solute (e.g. sucrose) is low. This could be called a weak or dilute solution. In a low concentration of water the amount of solute is high. This could be called a strong or concentrated solution. When a partially permeable membrane divides two such solutions, the water will move from the area of high concentration to the area of low concentration until both sides are equal. In plant cells water flows through the cell wall and cell surface membrane into the vacuole from the outside. As a result, the cell swells up. It doesn't burst as the cell wall stops the cell expanding too much; at this point we say a cell is fully turgid. Aim The purpose of my investigation is to investigate the factors affecting the rate of Osmosis. The key factors I have found affect this are: Length - of membrane Temperature - of water Concentration - of solution The factor I am going to investigate is the concentration of the solution in which the potatoes are placed. By doing this I will have to control all other factors to ensure a fair test, these are; doing all the tests at room temperature to control the temperature as a higher temperature would mean diffusion would occur quicker. ...read more.

Middle

2 for each test tube as it will be more accurate than 1 and give a more accurate result, as I will be able to then work out an average. * Find the mass of the potato pieces in grams correct to 2.d.p using electronic balance. If necessary cut a small piece off potato to make all pieces of an even mass. * Measure solutions into test tubes as follows; 1. 20cm distilled water, 0cm sucrose solution 2. 18cm distilled water, 2cm sucrose solution 3. 16cm distilled water, 4cm sucrose solution 4. 14cm distilled water, 6cm sucrose solution 5. 12cm distilled water, 8cm sucrose solution 6. 10cm distilled water 10cm sucrose solution Put solutions into test tubes and place in test tube rack. * Place 1 pin with 2 pieces of potato into the test tubes and place bung in. * Leave at room temperature out of direct sunlight for 24 hours. * After 24 hours I will take my results by re-measuring each potato mass and recording it. Results and Analysis The table below shows my raw data. The last column was worked using the formula; Mass after-mass before = change in mass Solution Mass before (g) Mass after (g) Change in mass (g) Reading 1 Reading 2 Reading 1 Reading 2 Reading1 Reading 2 0 moles 1.09 1.14 1.77 2.02 0.68 0.88 0.1moles 1.1 1.12 1.71 ...read more.

Conclusion

I also found my first set of readings unhelpful but as I had done 2 sets of readings I could take an average of the two to make my results more reliable. This did mean my overall percentage increase might have been slightly different, as these results would have affected them. If I did this experiment again I would be more careful in my setting up the experiment to ensure my results would be accurate. I had problems cutting the potatoes so they may have ended up slightly different sizes, which would account for any anomalous results. Another reason the results could have occurred may have been because the potato cores were not completely submersed in the sucrose solution. The final weighing may have not been accurate as not all the cores were blotted dry properly before weighing. Sugar solution sticking to the core would have increased the final mass artificially. To eliminate this bias I could have invented a universal blotting regime or measured length increase instead of mass. For a further experiment I could have investigated the effect other factors had on the rate of osmosis. The temperature of the water in the sugar solution is one. It would prove that the protein in the potato membrane denatures after the optimum temperature (usually about 35 degrees c.) and osmosis would no longer occur as the membrane is destroyed. Another factor that may have been investigated could be the increase in length of potato chip. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells 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 GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips.

    5 star(s)

    The cells become turgid as they take in more water. The affect that this has on the shape of the graph is that at the beginning, the line is relatively straight because osmosis has only just begun. However when the concentration of sucrose increases, the potato chips lose mass because

  2. Marked by a teacher

    An investigation into the factors affecting osmosis

    4 star(s)

    to swell up and become turgid, taking in all the water it can possibly take in. So I have chosen to leave it out due to our preliminary work, which showed that it would change a lot. With the potato in 0.2 molar solutions of sucrose, I don't think there will be much change in the weight of the potato.

  1. An Investigation of Factors Affecting the Rate of Osmosis.

    Why Use Potatoes 1) They are cheap 2) They have homogenous tissue. This means that they have the same type of tissue throughout the potato, and so results won't be indifferent or unfair. 3) The cell surface membrane acts as a semi permeable membrane, allowing osmosis to occur.

  2. An Investigation Into Factors Affecting The Rate Of Osmosis

    cells firm and turgid thus increasing the size and weight of the overall potato piece. However the cell does not rupture because the walls are very strong and thick. The cell is surrounded by a weak solution so there is not much change in the weight of the cell because

  1. Factors Affecting Osmosis.

    a dilute sugar solution) or pure water the water potential outside the cell is higher than inside the cell causing water to move into the cell so that it becomes turgid (swollen and hard). Turgidity in plant cells is very important to plants because this is what makes the plant "stand up" into the sunlight.

  2. Investigating the factors affecting the rate of osmosis in potato cells.

    The lower the solution's molarity, the more slowly the water will flow out of it, and possibly it will flow into it. Heat - if the water molecules are more agitated they will flow faster in the direction of the concentration gradient.

  1. To investigate the factors that effect osmosis in living tissue.

    to which the membrane is impermeable or less permeable. As we are discussing osmosis with regards to plants, I believe it is necessary that we consider the structure of plant cells. A simplified drawing of a leaf palisade cell3 is illustrated below: Within the cell there are two selectively permeable membranes, "one lining the outer surface of the cytoplasm

  2. An Investigation into factors affecting Osmosis in Potato Tissue

    Divide the potato cylinders into 7 sets of 3, and weigh their masses (to 2 decimal places) using the top pan balance, and note this down. 5) Prepare 25cm� of 7 sucrose solutions of different sucrose concentrations- use 0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1 molar solutions, and fill 7 beakers with these solutions.

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