Investigating Plant Growth Responses

• 1. put 10 cress seeds into three different petri dishes, each lined with moist filter paper, and label them A, B and C
  2. shine a light onto one of the dishes from above and two of the dishes from different directions
  3. leave the cress seeds for a week until you can observe their responses
• Control variables:

  • number of seeds - use the same number of seeds in each dish
  • type of seed - use seeds that all come from the same packet
  • temperature - keep the petri dishes in a place where the temperature is stable
  • water - use a measuring cylinder to add the same amount of water
  • light intensity - keep the distance between the bulb and the dish the same