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

The Effect of Different Concentrations of Water on Potato Tubes

Extracts from this document...


The Effect of Different Concentrations of Water on Potato Tubes Introduction I am going to investigate the effect of water concentration in a boiling tube on a potato tube. Plan To be accurate with my results I will have five tubes from the same potato in each of the water baths. This is because I can then have enough results to distinguish any anomalous points, and thus disregard them. This is because I would be able to take an average from the five results each time, making my results more accurate. Therefore, I will have five potatoes in five boiling tubes, thus I will have 25 potato tubes. Osmosis is a phenomenon that operates in the same way as diffusion of particles, but with water molecules. Therefore if I change the concentration of water in the water baths, and keep the concentration of water in the potato as constant as I can, then there should be a movement of water molecules. Therefore I predict that if the water concentration in the potato molecules is less then the concentration of water in the water bath, water will come in through the selectively permeable membrane into the potato, thus increasing the potato's area. This could also work the other way, if the water concentration is smaller then in the potato tube, water will comes through the semi permeable membrane into the solution outside. ...read more.


3 Apparatus * Boiling rack * 5 Boiling tubes * Cork borer * Distilled water * Potato * Scalpel * 2M Sodium Chloride * Tile * Volumetric pipette * Water resistant permanent marker * Weighing scales Method 1. Take an Estima potato of large size. With a cork borer, take out twenty-five pieces of equal cross sectional area. When using the cork barer use it on a tile so that the table does not get damages. Measure the weight of these tubes using a weighing machine making sure the potato tubes are dry. Set up the experiment as shown below. 2. In a boiling tube, add 40ml of water. Label this beaker, 1. Make the other four solutions as in Fig.3 below using a volumetric pipette. Place five potato tubes into each of the beakers. 3. Leave the beakers for twelve hours. 4. Use the same weighing machine to note the change weight of each potato tube, making sure they are dry. Record these measurements in a table like Fig. 2 5. Plot a graph of these results, and comment on your observations. Volume Water (cm3) Volume Sodium Chloride (cm3) Molar Solution of NaCl in the Boiling Tube (dm-3) Potato Tube Number Weight Difference (g) 40 (x5) 0 (x5) 0 (x5) 1-5 30 (x5) 10 (x5) 0.5 (x5) 6-10 20 (x5) 20 (x5) 1 (x5) 1-15 10 (x5) 30 (x5) 1.5(x5) ...read more.


This is because I feel those two points give me the accuracy to give me a firm conclusion. I also have enough results to give me a reliable conclusion and get rid of any anomalous points. To make the results clearer I will now show the total average mass change of each solutions and the average percentage change in mass for each solution. 0M NaCl Average Weight Change 0.22 (H2O) Average Percentage Change 24% 0.5M NaCl Average Weight Change -0.24 Average Percentage Change -26% 1M NaCl Average Weight Change -0.35 Average Percentage Change -33% 1.5M NaCl Average Weight Change -0.46 Average Percentage Change -43% 2M NaCl Average Weight Change -0.56 Average Percentage Change -47% Using this information, I have drawn graphs. Firstly, I have drawn a graph for each solution. This shows the mass change in each boiling tube, over 24 hours. I have then drawn a more conclusive graph showing the percentage change of each solution. I think that this is more conclusive because if a potato were heavier then normal, it would suggest it had a higher percentage of water in it. If I only drew graphs for the mass change, this potato would lose more water then the others, because it has a larger mass of water. However, using percentage change in mass makes the graphs fair, because it uses the mass change over the original, giving us a percentage of the original. The equation used for this was: Percentage Change = Change x 100 Original ...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 experiment to investigate how the effect of varying concentrations of salt solutions play ...

    4 star(s)

    This is because, by increasing the temperature, we increase the kinetic energy of the water molecules and thus they diffuse across the semi permeable membrane at a greater speed. Concentration Gradient: The concentration gradient is actually the difference in concentration between the two solutions, separated by the semi permeable membrane.

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

    The mass of the potato is a dependent variable, and this means that it will be measured throughout the experiment. I will measure the mass in grams. The potato chip will be measured before it is put in the solution, and after.

  1. Discover what effect water with different NaCl concentrations have on potatoes, and find out ...

    in section "C" will go flaccid, meaning that they would become soft and spongy. This is why I think that the farmer is correct, and it was the high salt content water in the flooding that caused the potatoes to become soft and spongy.

  2. Investigate what happens to a potato chip's weight when placed in different concentrations of ...

    I will measure this by using an electronic scale. The fixed variable is the factor that I will keep the same. I will keep the amount of solution I put into the beakers for each experiment the same by using a measuring cylinder.

  1. investigating how osmosis works against different concentrations of glucose

    x 1.5 4.6 x 1.3 Decrease The results were as expected; the potato in water expanded the most because water moved into the potato by osmosis. As there were more water molecules outside the potato than inside, water molecules moved through the semi-permeable membranes of the potato cells into the potato so it swells.

  2. Looking at how concentration affects the movement of water particles through a partially permeable ...

    Water passes into the cells by osmosis. But animal cells have no cell wall to stop them swelling too much - so they burst. We call this haemolysis. A constant blood concentration The red blood cells in this diagram have been placed in a concentrated solution Wtaer has moved out of their cytoplasm by osmosis.

  1. Investigating the effect of different concentration of glucose (C H O ) and salt ...

    The more solute molecules present, the more negative the water potential becomes (?). The amount by which solute molecules reduce the water molecules reduce the water potential of a solution is called its solute potential. It always has a negative value and is given the symbol ?

  2. Factors Affecting Osmosis.

    the surface area of the chip would be larger hence there would be more area over which osmosis would occur so the potato cylinder would loose or gain a larger volume of water than the remaining potato cylinders. I will control this variable by always using the same size borer (size 5)

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