osmosis

• Osmosis


  The movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
• Partially permeable membrane - Very small holes that only allow tiny molecules like water to pass through, but not larger molecules like sucrose
• Dependent variable is the chip mass, independent variable is the concentration of the sugar solution
• All other variables (volume of solution, temperature, time, type of sugar used, etc.) must be kept the same to make it a fair test
• Errors may arise from:

  not fully drying potato cylinders, excess water would cause higher mass

  if water evaporated from beakers, concentrations of sugar solutions would change
• the effect of sugar solutions on plant tissue:

  1. cut up a potato into identical cyclinders, put them into beakers with different sugar solutions. One pure water, one very concentrated sugar solution and a few others inbetween
  2. measure the mass of the cyclinders leave one cyclinder in each beaker
  3. dry them with a paper towel measure their masses again
  4. if water has been drawn out, theyll have decreased in mass. if drawn in water by osmosis, theyll have increased in mass