Transpiration

• What is the aim of the transpiration investigation?

  To investigate environmental factors affecting transpiration
• What equipment is needed for the transpiration experiment?

  • Potometer
  • Leafy shoot
  • Plastic bag
  • Fan
  • Water bath
  • Lamp
• Why should the leafy shoot be cut underwater?

  To prevent air bubbles from entering vascular tissues
• How can you ensure the potometer is airtight?

  By sealing gaps with vaseline
• What environmental factors are set up in the experiment?

  • Temperature
  • Humidity
  • Wind speed
  • Light intensity
• How can humidity be controlled in the experiment?

  By wrapping the shoot in a plastic bag
• What is the purpose of using a fan in the experiment?

  To vary the wind speed affecting transpiration
• How can light intensity be varied in the experiment?

  By changing the distance of the lamp from the shoot
• What should be recorded after setting up the apparatus?

  The starting position of the air bubble
• How long should the apparatus be left before recording the final position?

  For 1 hour
• What calculations should be performed after the experiment?

  Calculate distance moved and volume of water absorbed
• Why should steps 1-8 be repeated with changing factors?

  To observe the effect of each environmental factor
• What should be plotted on the graph after the experiment?

  • 'Factor' on the x-axis
  • Volume of water on the y-axis
• What is a potential hazard when cutting the leafy shoot?

  Be careful when cutting underwater
• What are the sources of error in the transpiration experiment?

  • Plant dying when cut
  • Water used for photosynthesis
  • Temperature changes affecting results
• Why should water be kept away from electrical outlets?

  To prevent electrical hazards