• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12

Osmosis. In this investigation we are going to be monitoring the sucrose sugar solution concentration change on the mass of a potato.

Extracts from this document...

Introduction

Coursework - Osmosis In this investigation we are going to be monitoring the sucrose sugar solution concentration change on the mass of a potato. We are basing our investigation on the process of osmosis. This is the net movement of water molecules from a region of their higher concentration to a region of their lower concentration, through a partially permeable membrane: Water molecules move from where there is more water, to where there is less, as long as the membrane separating each is partially permeable. The cell membrane, which is a type of lipid, allows water to pass through it. Therefore, many water molecules are moving in each direction. When it is found out that a change in mass has happened in either substance it is because there has been a large movement of water molecules in one direction to make the concentration equal in both substances. This could be explained with the collision theory and looking at the diagram above. When there is an equal concentration of water on each side then the water molecules will pass through each side of the membrane at the same rate, so that one side is replacing what has gone out of the other side. This will maintain an equal balance of water molecules on each side. However, with our experiment and shown in the diagram above, one side (left) has a lower concentration of water molecules as it has glucose molecules too, when the other side has the equivalent but just with water molecules. Therefore it has a higher concentration. Because the membrane only allows water molecules to pass through it, the glucose molecules get stuck preventing water molecules to get through and therefore disturbing the normal rate of water movement. Now that is happening, less water molecules on the left are passing to the right because they have less space to transfer molecules. However, on the right side the same rate of movement is going on and so the water molecules on the right ...read more.

Middle

(The possible outcome variables are highlighted, standing out from the rest of the text) Out of all these possible outcomes, I will still be looking at the percentage change in mass of the potato chip, as this will be the most accurate and precise result. This is because the change in volume and concentration of sugar will be too difficult to measure. The change in the length of the potato Chip will only be very small and very difficult to determine. The change of mass of the potato chip will not be very precise, as I am not controlling the starting mass. After discussing in detail above how osmosis happens and looking at the factors that determine the rate of osmosis, I have come to the prediction that the larger the difference in concentration between the two substances, the faster the rate of osmosis or the more the osmosis will take place. The bigger the concentration, the more osmosis is needed to lose water or absorb water and make both substances equal. If the concentration of glucose in the potato chip is higher then water molecules will pass from the solution into the potato chip, therefore, increasing the mass of the potato chip and making it grow in size. However, if there is a higher concentration of glucose in the solution, then water molecules will pass from the potato into the solution, therefore, decreasing the mass of the potato and making it shrink in size. So therefore, I definitely believe that a change in the concentration of the solution will have some kind of effect on the mass of the potato chip, due to osmosis. Knowing my prediction I am now going to write out a suitable method for my experiment and then carry out this method as accurately as possible: * Firstly I will prepare the solutions by putting them in test tubes with the concentrations of 0%-25% sugar solution. ...read more.

Conclusion

When 10% is added the potato loses 0.12 grams. From then on the changes get bigger because we are then just adding to the concentration and making the difference between the two substances even bigger. This means that osmosis has to work at a faster rate or osmosis will have to take place a lot more and therefore, there will be a bigger loss in weight. This is shown as we get a decrease of 0.27 grams with 15%, followed by a decrease of 0.38 grams with 20% concentration and finally the biggest being a 0.41 gram decrease with 25% concentration added in. The concentration of sugar solution and the average percentage increase are inversely proportional. This means that as the concentration of sugar solution goes up, the average percentage increase goes down. You can see this clearly in my graph: Looking at my graph I can clearly say that it justifies my prediction about osmosis in our experiment. Like I stated before, it follows a negative correlation and this is what I said in my prediction too; In my prediction I said that the larger the difference in concentration between the two substances, the faster the rate of osmosis or the more the osmosis will take place. This is true with the experiment because when the concentrations got bigger, this added a bigger difference between the two substances and therefore there was a bigger change in mass to transfer the difference in water to the other substance. On the graph you can see that the bigger the concentration, the bigger the decrease in mass, as it is quite proportionally going down in a negative correlation. Also in my graph you can clearly see the difference between 0% concentration and a 25% concentration sugar solution, when added to the distilled water. When it has 0% there is a 0.15-gram increase, but when there is 25% sugar concentration in the solution there is a 0.41-gram decrease. This means that there is a 0.56-gram difference in the increase and decrease put together, which shows the difference between the two. Luca Capobasso ...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

    Biology Coursework - Osmosis

    5 star(s)

    The effect this had on the potato, was to fill it's cells up with more water than before, this means that the cells were under higher pressure, which caused the cells to swell and become turgid. In my opinion the most interesting solution was 0.5M, in this solution, the potato

  2. Marked by a teacher

    How does the concentration of a sucrose solution affect the rate of Osmosis in ...

    5 star(s)

    1 hour, to make sure that the results are valid, as this too could alter the reliability of the results I collect. If they are in the water for different amounts of time then it would be unfair as some potatoes would have more osmosis happening to them.

  1. Marked by a teacher

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

    5 star(s)

    I shall use a chipper. This is a piece of apparatus that cuts potatoes fairly accurately. Unlike the inaccuracies when using a knife, the chipper ensures that each potato chip has the same cross - sectional area. There will still be errors due to the length at which the potato

  2. Marked by a teacher

    Investigating the effect of sucrose concentration on osmosis in potato cells

    4 star(s)

    But the potato did not gain as much mass as in distilled water, because the water potential of the 0.2 M solution is lower than that of the distilled water, so not as many more water molecules moved across from solution to cell than from cell to solution, so the concentration gradient is smaller.

  1. Marked by a teacher

    Science Coursework: Investigating Osmosis in potato tissue

    4 star(s)

    7.43 7.58 Size (cm) 3.5 3.7 Then we filled one of the beakers water with 3 spatulas worth of salt. That then became the salt solution of the two. Then at the same time we placed the two bits of potato into their respective solutions and began the timer.

  2. Experiment investigating concentration of sucrose solution and potatoes

    * Use the same scales for each weighing. You do this so if the scale it faulty all your results will be fair as they would all be heavier by how ever many grams it is. Prediction: For this trial experiment I think that none of the potatoes will change

  1. Aim: To find out the effect of altering the concentration of sugar solution on ...

    I will then add a potato chip to a particular amount of concentration of sugar solution and water in the test tube. To pour the sugar solution and water into the test tube, I will be using a 10ml measuring cylinder.

  2. Osmosis investigation

    I will be taking results at 0.2Molar intervals. From my preliminary I found that the 0.0Molar reading was valuable and important to include in my experiment as it shows the effect of osmosis very strongly as there is a very high water potential. For that reason, my concentration readings start at 0.0Molar- that is in fact tap water.

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