Potato IA Lab. This experiment tested osmosis when dealing with different concentrations of salt on the outside of the membrane.

Authors Avatar

Abstract:

        Osmosis is the diffusion of water across a semi-permeable membrane. This experiment tested osmosis when dealing with different concentrations of salt on the outside of the membrane. If there is a higher concentration of salt on the outside of the membrane, then water will move across the membrane to the outside in order to reduce the concentration of salt. This hypothesis was supported by the data from this experiment because it shows the weight of the potato cores decreased at higher levels of salt concentration.

Introduction:

        The purpose of this experiment was to show the relationship between osmosis and the salinity in a solution. Water naturally diffuses across membranes from areas of lower salinity to areas of higher salinity. Osmosis is the net movement of water across a selectively permeable membrane driven by a difference in solute concentrations on the two sides of the membrane. (Bowen, 2000). When the concentration of dissolved salt is greater outside the semi-permeable membrane, the solution is hypertonic and water will diffuse across the membrane from the inside to the outside in order to reduce the salinity outside the membrane (Gross, De Zeeuw & Simpao, 2001). “Water molecules are able to pass through most biological membranes, so salinity imbalances within biological systems are naturally corrected via the diffusion of water across semi-permeable membranes to equalize salt concentrations on both sides of the membrane” (Gross, De Zeeuw & Simpao, 2001). If there is a higher concentration of salt on the outside of the membrane, then water will move across the membrane to the outside in order to reduce the concentration of salt.

Join now!

Variables:

        Independent variable: Salt concentration

        Dependent variable: Weight of potato cores

        Constants:

Amount of distilled water

        Water temperature

        Size of potato cores

        Type of potatoes

        Type of salt

        Room temperature

Apparatus:

  • 5 Red potatoes
  • 1500 mL distilled water
  • 15 Plastic cups
  • Table salt
  • 500 mL beaker
  • 100 mL graduated cylinder
  • 1 cm diameter corer
  • Stir plate
  • Permanent marker
  • Knife
  • Ruler
  • Thermometer

Procedure: 

        Using the permanent marker, 5 cups were labeled 0.0 M, 5 cups were labeled .5 M, and 5 cups were labeled 1.0 M salt. 100 mL was measured in the graduated ...

This is a preview of the whole essay