• 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...

Introduction

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.

Middle

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.

Conclusion

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)

    With both of these sources, the potato will keep on working until it dies of either lack of water or too much water, or will stop, as both sides would become equal, making no more reactions. When the concentration gradient is lower in the potato, the water will transfer from the solution into the potato.

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

    One result may not be accurate because of human error, so to eliminate all possibilities of inaccuracy I will repeat it. I must also do at least 5 types of concentrations, to have sufficient results and to see if

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

    In my investigation I am going to concentrate on the affect of concentration on the rate of osmosis between a glucose solution and potatoes chips. Plan I am going to monitor how the concentration of glucose solution affects the rate of osmosis in potato chips.

  2. 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

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

    solution of 20% sugar, a solution of 30% sugar, and a solution of 40% sugar. Obviously, I may not find the exact concentration of cell sap in one of these readings, but by comparing the results of each I can produce an estimate.

  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. An Investigation of Factors Affecting the Rate of Osmosis.

    to move quickly, but in high pressure they are being pushed across to the low concentration. Hypothesis I believe that the bigger the difference in water potential the quicker the molecules will move and the quicker the rate of osmosis will be. Why Use Potatoes 1) They are cheap 2)

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

    Surface area of potato - the more surface area the potato cells have, the faster the rate of osmosis will be, as more cells will be in contact with the solution. The easiest and most accurate of these to measure is concentration, as concentration can be easily controlled and quite easily measured.

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