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

What are the factors affecting osmosis?

Extracts from this document...


AT1 Experimental Investigation What are the factors affecting osmosis? Background Knowledge Osmosis Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration. Semi-Permeable membrane allows small molecules to pass through, but prevents large molecules from passing through. In this diagram, the left side of the membrane has a higher concentration of glucose. The concentration wants to be the same on both sides of the membrane. For this to happen, the water on the right side, in the lower concentration moves to the left, making the concentration higher on the right and lower on the left, until they become equal. Consequently, there would be more liquid on the left side than on the right, and is shown on the diagram. When this happens in plant cells, water continues to enter the cell vacuole until the turga pressure of the water in the cell equals the cell wall pressure. Osmosis then stops, even if the concentration is still different. The cell is then Turgid. Because the plant cells take in water through osmosis, the mass of the plant increases, as does the length and width of the plant. ...read more.


Apparatus list * Scalpel * Top Pan balance * Beakers * Stop-watch * 10mm Cork Borer * Glucose solutions at 0.2M, 0.4M, 0.6M & 0.8M * Pure water * ruler Diagram Results chart Concentration Original Mass (g) Final Mass (g) Change in Mass Average change Distilled water 1.61 1.68 1.74 1.82 +0.13 +0.14 +0.135 0.2M 1.74 1.72 1.64 1.76 -0.10 +0.04 -0.03 0.4M 1.69 1.72 1.69 1.71 0 -0.01 -0.01 0.6M 1.71 1.74 1.69 1.71 -0.02 -0.03 -0.025 0.8M 1.74 1.70 1.63 1.60 -0.11 -0.10 -0.105 Analysis The question that I asked at the beginning of the investigation was; "what are the factors affecting osmosis?" I have investigated the effect of the concentration of glucose on osmosis, using the change in mass to measure the effect. My results show that the plant at first gained mass as it took in water, with the potato in the distilled water taking on the most, and the 0.2M taking on less, but still an notable amount. The plant then lost mass, as it lost water, with the potato in the 0.4 and 0.6M concentrations losing just a little, but the 0.8M losing more. ...read more.


Since we measured to 2 decimal places for the mass and used sharp enough scalpels to measure the length to 0.5mm, the accuracy should be very good, and I think our results reflect this. The only thing that may be slightly inaccurate was the timing using stopwatches, because this depended on us stopping them at the right time, and removing the potato promptly, which could be somewhat imprecise. However, osmosis is a fairly slow process, so this should not have impacted on our results in any obvious way. If I were to repeat the investigation, one improvement I could make would be to increase the volume of liquid I used to submerge the potato in. This means that the potato would be completely covered, so that concentration would not change as it would if the potato was partly in the air. Also, leaving the potato in the liquid longer would give us more apparent results, with bigger differences in mass and length, as the osmosis would have longer to work. Extensions could include looking at other plants, to compare the glucose concentration of the cells. However, perhaps one that would extend our particular investigation more specifically would be to do more experiments using more concentrations between about 0.35M and 0.5M to try to pinpoint the exact concentration of the potato cells. ...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

    An investigation into the factors affecting osmosis

    4 star(s)

    In the distilled water, I believe that the water is more concentrated in the potato, and therefore the water should transfer from the water to the potato, making the potato bigger in size, and heavier in weight. The potato tissues, being surrounded by a weak solution, will be most likely

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

    Therefore at this point no mass change will occur. When the solution outside the potato is lower than the equilibrium, then it will cause the potato to gain mass. This is because the water moves into the potato from the concentration, because the potato has less water than the solution.

  1. Osmosis is defined as 'the movement of water molecules from an area of high ...

    This shows that my results are fairly reliable. My graph fits in with my prediction of the experiment graph. The percentage gain/loss in mass homosexual are not directly proportional are not directly proportional to each other, so I decided to test another simple way of seeing whether the results are related.

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

    Different molarity solutions of sucrose can be composed and used along with certain amounts of potato to find the rate of osmosis. Hypotheses I predict that the potato cylinders in the higher concentration sucrose solutions are more likely to lose mass through osmosis, and in the lower concentration solutions the

  1. Factors Affecting Osmosis.

    or plasmolysed. When what I have stated above occurs the plant cell decreases in mass because water has left the cell. An everyday example of this involves ocean water which generally contains higher concentrations of solutes (roughly 3.5 grams of salt for every litre of water), therefore most land plants

  2. In this experiment I intend to investigate the effects of osmosis on potato cells. ...

    For example, I will measure the potato samples to the nearest mm, the volume of solution to the nearest ml, and the weight of potato samples to the nearest 2dp. This is necessary because I do not know how large any changes will be.

  1. The Effect of Glucose Concentration on the Rate of Osmosis

    It acts like a surface which sticks particles on it and force them to collide. When the reaction mixture is heated the particles acquire more energy and start moving around faster which will allow more collisions per second, as the particles will be more likely to collide with each other successfully with high energy.

  2. Investigating the Factors affecting the water relations of plant cells.

    A plant cell in a dilute solution 1 Cell wall 2 Cell membrane 3 Nucleus 4 Vacuole 5 Osmosis takes place into the cell: water passes through the cell wall, diffuses through the partially permeable cell membrane and the cytoplasm and enters the vacuole. The cell swells and becomes turgid.

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