Title: An investigation into the affect of different concentration salt solutions on potato tissue

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Damanjit Khakh

10 Orange

Biology Coursework

BIOLOGY COURSEWORK

MRS HANDA

DAMANJIT KAUR KHAKH

10 ORANGE

Title: An investigation into the affect of different concentration salt solutions on potato tissue

Aim: .I have to find out the effect of varying salt concentrations on a potato tissue. Also to find out how osmosis occurs with different salt concentrations from very dilute to very concentrated. I will be looking for any changes in mass and length

Prediction: I predict that the most concentrated salt solution (1 molar) will be the solution that will have the most dramatic effect upon the tissue of the potato. As the solution goes down the line in other words gets more and more dilute or weaker it will have a less distinctive effect upon the potato tissue. This will happen due to the high concentrated solution i.e. the 1 molar salt solution moving across into a low concentrated are i.e. the potato chip. The potato chips that are in the most concentrated solutions will be the ones, which will lose mass. The potato chips which will be in the diluted solutions will gain more mass this is the actual osmosis scientific theory. Osmosis is the movement of water molecules from an area of high water concentration through a semi-permeable membrane to an area of low water concentration. This is very similar to diffusion and active transport.

Osmosis Theory

Solution A        Solution B

Partially Permeable Membrane

Key

= Solute Molecules

= Solvent Molecules

Preliminary Experiments: Visking Tubing Experiment

Visking Tubing

This is a thin plastic with microscopic holes, which allow small molecules to pass through

Aim

To observe the process of osmosis in an experiment

Apparatus

  • 2 Beakers filled with sodium chloride of different concentrations
  • 2 Visking tubes filled with water
  • Elastic Band

Diagram

        0.8 solutions

                             

Beaker    

O.2 solution                                      

Visking Tubes

Method

  1. Tie one end of a Visking tube with a rubber band tightly
  2. Fill the Visking tube up with water and seal the remaining end with another band
  3. Do this for 2 tubes
  4. Fill one beaker with sodium chloride 0.2 solution
  5. Fill the other beaker with sodium chloride solution 0.8
  6. Drop 1 Visking tube in each beaker and wait 20 minutes

Conclusion

The process of osmosis has taken place in the two beakers. The concentration level of NaCl 0.2 was low therefore the tube was harder than the other tube. More water moved out from the tube in concentration 0.8 NaCl than in the low concentration NaCl of 0.2.

Variables

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Apparatus

Potato x 1-this will be our experimenting tissue. It will have to be the same potato and will have to be treated in the same way.

Blotting Paper x 2-I will use this after my experiment. I will take of any excess water of the disc when I am measuring the mass after.

100ml Beaker x 6-A test tube would be too small and there would be a danger of spillage. As we are only using 50cm3 of solution there will this beaker is more suitable

100ml Measuring Cylinders x 2-As both ...

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