Osmosis

• What is independent variable(change)


  Concentration of salt or sugar solutions
• What is dependent variable (measure)


  Change in mass of potato pieces
• What is control variable(same)


  volume of solution, temperature of the solutions, time in the solution
• What causes change in mass of potato cylinders


  Movement of water by osmosis
• Water will move into the potato cells via osmosis.


  if the solution is less concentrated than the contents of the potato cells
• Water will move out of the potato cells via osmosis 


  the solution is more concentrated than the contents of the potato cells
• A potato and a cork borer, to make potato cylinders. A ruler with a mm scale and a sharp knife, to cut the cylinders to the same length. 4 different sugar solutions of different concentrations (0.25−1.0 mol/dm3). Distilled water, to use as a control solution. A measuring cylinder and boiling tubes, to measure out the different solutions. Paper towels, to dry the potato cylinders. A top-pan balance accurate to at least 0.01 g, to weigh the potato cylin
• Step 1: Using the cork borer, create five potato cylinders. Step 2: Cut the cylinders to approximately the same size using the ruler and knife. Step 3: Use a paper towel to remove any surface moisture from the potato cylinders. Step 4: Weigh each potato and record the mass. Step 5: Measure out the same volume of each concentration of sugar solution into different boiling tubes.
• Step 6: Measure out the same volume of distilled water into another boiling tube, to use as a control. Step 7: Place each potato cylinder into a different boiling tube and leave them for 30 min
• Step 8: After 30 minutes, remove the potato cylinders, gently roll them on a paper towel and reweigh them. Step 9: Record the mass of each potato cylinder in a results table.