osmosis

• Osmosis

  The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
• Water concentration

  The amount of water as compared to the other molecules like sugars or salts that are dissolved in that water
• Solutes are the dissolving molecules in water
• Higher solute concentration


  Lower water concentration
• Lower solute concentration

  Higher water concentration
• Osmosis in cells

  Water particles diffuse from outside the cell (higher water concentration) down the concentration gradient into the cell (lower water concentration)
• Measuring sugar concentration in a vegetable

  1. Get a potato

  2. Use a borer to remove cylinders of potato

  3. Cut the cylinders to the same length

  4. Measure initial mass of potato cylinders

  5. Place potato cylinders in different sugar solutions for 30 minutes

  6. Remove potato cylinders, dab dry, and measure final mass
• Control variables

  • Species of potato
  • Age of potato
  • Surface area and volume of potato cylinders
  • Volume of sucrose solution
  • Temperature of solutions
  • Time potato is in solutions
• Potato cylinders in different sugar concentrations

  Have different final masses
• Percentage change in mass

  Calculated as: (Final mass - Initial mass) / Initial mass x 100
• Analysing results

  1. Plot percentage change in mass vs sugar concentration

  2. Draw line of best fit

  3. Find sugar concentration where percentage change is zero
• The sugar concentration inside the potato is approximately just below 0.6 moles