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

To investigate and find out the osmotic potential of a potato.

Extracts from this document...

Introduction

BIOLOGY COURSEWORK: OSMOSIS AIM: To investigate and find out the osmotic potential of a potato. PREDICTION; I predict that the potato cores in the distilled water and weaker solutions, which contain low concentrations of salty water, will expand when left in the solution for a certain amount of time. I say this because the molecules in the weaker solution will diffuse to an area of higher solute concentration, the potato (which will be done by osmosis). I also predict that the potato cores in the 1.0 molar concentration of brine (highest concentration) will shrink this is because the molecules in the potato will diffuse in to the brine. This will also be done by osmosis, is the movement of water molecules from an area of weak solution to an area of strong solution through a semi-permeable membrane (cell membrane). Therefore the potato cores once left in the higher concentrated solutions will shrink. And the potato cores in the weaker solutions will expand. THEORY: Osmosis is defined as 'the movement of water molecules from an area of high water concentration to an area of low water concentration, across a semi-permeable membrane' (Collins, 1999). ...read more.

Middle

Therefore when osmosis does take place the mass and length of the potato cores will show if it has expanded or shrunk. SAFE TEST: To ensure that the experiment is safe I will have to do the following: * Be careful when handling glass objects such as the test tubes and other apparatus. * Be careful, not to spill solution * To make sure that all chairs are tucked in and coats and bags are hung up in the corner away from the experiment to avoid any accidents. * To make sure that all surfaces are clean and clear of any unwanted objects. * Make sure hands are washed before and after experiment. VARIABLES: The variable of this experiment is that different concentrations of salt water will be used. The concentrations being used are written below: * Distilled water (D/W) * 0.2 * 0.4 * 0.6 * 0.8 * 1.0(brine) There will be seven different concentrations to see what will happen to the mass of the potato in different concentrations of salt solution. APPARATUS * POTATO * POTATO CORER * 6 GLASS TEST TUBES * MEASURING CYLINDER * TEST TUBE RACK * DISTILLED WATER * BRINE * RULER * KNIFE * FILTER PAPER * MEASURING SCALES DIAGRAM: (please turn over and look at the next page) ...read more.

Conclusion

My results and graph show that my theory was right. My results do agree with my prediction. Which stated that the mass of the potato cores would decrease in the higher concentrations and increase in the lower concentrations. Therefore as my theory did state that osmosis is the movement of water molecules through a semi permeable membrane from an area of low concentration to an area of high concentration. EVALUATION: The experiment was easy to do. The results were right but not really accurate. The graph shows that something went wrong in the 0.4m concentrations. I think that the volume of liquid might have not been measured accurately. To improve my results I will have to follow my method more accurately. Take measurements of the volume of liquid more accurately. I could have repeated the experiment more than twice. I did do the experiment twice to get the average results. Over all I think the experiment went quite well. If I were to do the experiment again I would follow the method more accurately to obtain more accurate results. Also try to prevent any errors by keeping an eye on the experiment. 1 ...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. Investigating the cellular water potential of potato cells.

    I predict that as the concentration of sucrose solution increases, the percentage change in mass of the potato will decrease. This is because as the concentration of sucrose solution increases; the solute potential increases, decreasing the water potential of the solution, therefore decreasing the amount of water molecules that will

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

    osmosising and the water molecules in the solution will be able to pass through the semi-permeable membrane of the potato sample. However the sugar molecules will not be able to pass through and therefore if no sugar molecules pass through the potato will become equally balanced with the water outside

  1. INVESTIGATING OSMOSIS AND WATER POTENTIAL IN POTATO CORES

    VARIABLES To make sure that the results obtained are reliable it is important that a fair test is planned and carried out. Below are listed the variables and also the variables that will be kept constant as to make sure that the experiment is a fair test.

  2. The osmotic potential of a potato

    upright to prevent spillages - Slate - to keep the desk clean - Knife - to cut the pieces of potato - Cork borer - to extract cylinder shaped pieces of potato out of the potato - Syringe with measurements imprinted on the side (2)

  1. Use scientific knowledge and practical skills to determine the effect of a range of ...

    This is because the cell is fully turgid and no more water can enter. At point C (low water concentrations), there is no indication that the cell is decreasing further in size. This is because the cell is fully plasmolysed and no more water can leave the cell Fair test:

  2. To find the osmotic pressure of potato cells.

    Plant Cells In plants the cells the Cell Wall will limit the amount of water that enters the vacuole by osmosis. When a cell is swollen with water it is called turgid because the cell membrane is pushes against the cell wall, the pressure is at maximum when the wall stretches and cannot take any more water.

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