Required Practical 8: Plant Responses (T)

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

  Investigate light or gravity effects on seedlings
• What is the independent variable in the light intensity experiment?

  Light intensity
• What is the dependent variable in the light intensity experiment?

  Height of the seedlings
• What is a control variable in the experiment?

  Volume of water
• How many mustard seeds are placed in each dish?

  10 mustard seeds
• Why is it important to have the same number of seedlings in each dish?

  To ensure a fair comparison
• What should you do if one dish has more seedlings than the others?

  Remove seedlings to equalize numbers
• How do you measure the height of each seedling?

  Use a ruler while holding the stems straight
• Where should the dishes be placed for the experiment?

  In full sunlight, partial light, and darkness
• How often should you measure the height of the seedlings?

  Every day for at least five days
• What should you do with the results after the experiment?

  Calculate mean height and draw diagrams
• What is phototropism?

  Growth towards the light source
• Why do seedlings grow towards the light?

  Auxin concentrates on the shaded side
• What happens to seedlings kept in the dark?

  They grow rapidly trying to reach light
• Why do leaves of dark-grown seedlings appear small and yellow?

  They cannot photosynthesize without light
• What happens to the shoots and roots when seedlings are placed on their side?

  Shoots grow upwards, roots grow downwards
• How does auxin affect root growth in response to gravity?

  Auxin builds up on the lower side
• What is the effect of gravity on the direction of root growth?

  Roots grow downwards towards gravity
• Where can you find questions on this required practical?

  In the vision workbook