osmosis practical

• What should you be able to describe by the end of the video?

  Investigate the effect of osmosis on plant tissue
• What is osmosis?

  Diffusion of water through a membrane
• What happens to plant cells when placed in water?

  Water moves in, causing cells to expand
• What occurs when plant cells are placed in a concentrated solution?

  Water moves out, causing cells to shrink
• What is the common vegetable used to investigate osmosis?

  Potato
• Why do we peel the potato before the experiment?

  The skin can affect osmosis
• What tool is used to produce potato cylinders of the same diameter?

  Cork board
• What length should the potato cylinders be trimmed to?

  About three centimeters
• Why is it important to use cylinders of the same length?

  To accurately measure the effect of osmosis
• What is added to the first test tube?

  10 cm³ of 0.5 molar sugar solution
• Why do we use distilled water instead of tap water?

  Distilled water contains no dissolved substances
• What should be done after leaving the potato cylinders overnight?

  Gently roll them on paper towel
• What is the purpose of rolling the cylinders on paper towel?

  To remove surface moisture
• What must be measured again after removing the cylinders?

  The length and mass of the cylinders
• How do you calculate percentage change?

  Change in value divided by original value
• What is the percentage change if the starting mass is 1.56 grams and increases by 0.25 grams?

  +16.03%
• What is the percentage change if the starting mass is 1.32 grams and decreases by 0.19 grams?

  -14.39%
• What does the graph of percentage changes in mass show?

  Mass gain in water, loss in sugar solution
• What does it mean when the graph crosses the x-axis?

  No change in mass occurs
• What concentration indicates no overall osmosis?

  Approximate concentration inside the cell
• What are the steps to investigate the effect of osmosis on plant tissue?

  1. Peel the potato.
  2. Use a cork board to create cylinders.
  3. Trim cylinders to the same length.
  4. Measure length and mass of cylinders.
  5. Place cylinders in different sugar solutions.
  6. Leave overnight for osmosis to occur.
  7. Roll cylinders on paper towel.
  8. Measure length and mass again.
  9. Calculate percentage change.
• What are the key factors affecting osmosis in this experiment?

  • Concentration of sugar solution
  • Length and mass of potato cylinders
  • Type of vegetable used
  • Time allowed for osmosis
• What is the significance of calculating percentage change in this experiment?

  • To quantify the effect of osmosis
  • To compare results across different solutions
  • To analyze the relationship between concentration and osmosis