osmosis practical

• independent variable

  • solute concentration
• dependant variable

  • change in mass of potato cylinders
• control variables

  • temperature
  • surface area of the potato
  • volume of solute solution
• method

  1. use a cork borer to cut 5 potato cylinders, same diameter
  2. use a scalpel and a ruler to trim and make sure they are the same length (3cm)
  3. measure the mass of each potato cylinder
  4. add 10cm 3 sugar solutions to your labelled boiling tubes (0.2, 0.4 and 0.6) then one very concentrated sugar solution and one pure water
  5. leave them for 24 hours
  6. remove the potato's from each beaker and pat them dry
  7. record the final mass
• if potatoes are placed in a higher solute concentration

  • they will loose water and there mass will decrease
• if potatoes are place in a lower solute concentration

  • water will be drawn in from a very dilute solution to a very sugar concentrated solution via osmosis and will increase the mass