An investigation to demonstrate the effect of different sucrose concentrations on potato tissues.

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Mohammed Rattansey LVE

An investigation to demonstrate the effect of different sucrose concentrations on potato tissues.

OSMOSIS: Osmosis is the passage of water from a region of high water concentration through a partially permeable membrane to a region of low water concentration.

My main aim is to find out if different concentrations of sucrose solutions cause the mass of a potato chip to increase or decrease. I plan to use 5 different concentrations of sucrose solutions, and for each concentration I will take 3 results. This will determine how much osmotic activity has occurred.  I will then find the average weight change for each result. Finally, I will find the average weight change and the average percentage change.

The Preliminary Osmosis experiment.

Apparatus

  • Potato chips
  • 1 measuring cylinder
  • 3 test tubes
  • 1 test tube rack
  • the concentrations of sugar solutions ( 0.5M, 1.00M )
  • distilled water (0.00M)
  • Electronic scales
  • 1 scalpel
  • 1 ceramic tile
  • sticky labels
  • paper towels
  • 1 ruler

Method

  1. I took 3 potato chips from the table, and cut them up into 3 cm lengths, using a scalpel. I had to be very careful whilst using the scalpel because it was extremely sharp.
  2. Then, I placed them onto a ceramic tile to avoid any dirt reaching it. This is because dirt could hinder the progress of osmotic activity, and also the dirt could add weight, and therefore mass to the potato.
  3. I then separately weighed the 3 potato chips and recorded their masses.
  4. Taking a test tube rack I placed 3 test tubes in it labelling them 1, 2 and 3 using sticky labels.
  5. I put a single potato chip into each of the 3 test tubes.
  6. Using a measuring cylinder, I measured 10 cm3 of different sucrose solutions and 10 cm3 of distilled water, which I then poured into the test tubes.
  7. I swiftly placed my potato chips into the test tubes
  8. I left the test tubes for 40 minutes to allow time for any osmotic activity to occur.
  9. Whilst I was waiting I drew up a basic table of results.
  10. After the 40 minutes had passed, I drained out the solutions in the sink
  11. The potato chips were taken out of the test tubes and dried using a paper towel.
  12. Each chip was then weighed using accurate electronic scales and the results were recorded.

Results

From the above results it can be seen that with the distilled water the potato becomes turgid and therefore it would cause an increase in the mass.  However, with the 0.5 M and the 1.00 M sugar solution the potato becomes flaccid and therefore causing a decrease in the mass of the potato.

From the graph and the line of best fit it can be assumed that, with an increase in molar concentration of the sugar solution, the percentage change of the potato  decreases. This means that osmotic activity decreases.

Certain Criteria to be Included in the Actual Experiment.

  • The independent variable I will choose to investigate in my actual experiment will be the concentration of the Sugar Solution.

  • The Volume of solution in each of the test tubes will be 10 cm3, because in my preliminary experiment I used 10 cm3 of each sugar solution and distilled water, and that was sufficient enough to get decent  results.
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  • The Suitable control in my actual experiment will be the temperature. The actual experiment will be conducted under room temperature. This is because if the temperature under which my experiment will take place in, is greater than room temperature, then, the rate of osmotic activity will be higher. If my experiment was conducted under a temperature that is lower than room temperature, then, the rate of osmotic activity would be at a slower rate. Therefore, constant room temperature is required as a suitable control.

Fair Test

        To create a fair test certain aspects of the experiment will ...

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