When the water potential of the surrounding solution is less negative
than that of the potato cells, water enters the cells’ vacuoles by
osmosis causing the turgor of the cells to increase.
1. Using a cork borer remove a core of potato.
2. Use a white tile to push the cork borer into the potato.
3. Using a scalpel or razor blade cut the skin off the ends of the
4. Cut the potato cores into 30 disks 5mm thick, using a ruler to
measure the thickness.
5. Place the disks into a petri dish to prevent the evaporation of
6. Make different concentrations of sucrose solution 0.1, 0.2, 0.4,
0.6, 0.8 molar and distilled water. Place the solutions into a water
bath to keep then all at the same temperature.
7. Remove 6 disks at a time from the petri dish and weigh them using
an electronic balance. Record the weight of the potato chips. Then
place in each different solution.
8. Shake solutions every 10 minutes. After 1 hour remove the disks
from the solutions, blot dry and reweigh.
9. Then repeat the experiment 3 times so an average of results can be
taken to give a more accurate result and show any anomalies.
Independent variable-Different solutions
The independent variable in the experiment is the different
concentrations of solution.
I am going to make the following solutions using salt and water.
0= pure water
1= NaCl (salt)
1 mole= Relative molecule mass (g) dissolved in 1000cm3 of water
58.5g (NaCl) in 1000cm3 water = 1 molar solution
5.85(g) in 1000cm3 of water = 0.1 moles
0.1molar = 0.585(g) in 100cm3 water
0.2molar = 0.585(g) X 2 in 100cm3 water
0.4molar = 0.585(g) X 4 in 100cm3 water
0.6molar = 0.585(g) X 6 in 100cm3 water
0.8molar = 0.585(g) X 8 in 100cm3 water
Size of potato chips – All of the potato chips must be cut with the
same cork borer, and me measured with a ruler t ensure they are all
5mm thick. This is to ensure accurate results and that the experiment
is fair. In addition to this the potato disks must be placed in a
petri dish to prevent the evaporation of water, to again keep all of
the potatoes the same size. This is to ensure the same surface area.
Amount of solution- The amount of solution used in each test tube must
be kept the same to make sure the results are accurate and fair. To
ensure the same amount of solution is used you can measure the
solution using a measuring cylinder
Temperature- The temperature must be thermostatically controlled using
a water bath to ensure the solutions are kept at the same temperature,
as a variation in temperature would lead to inaccurate results.
Time- All of the potato chips must be kept in the solution for the
same amount of time to make it a fair test. Using a stop clock to...