plant growth prac

• Investigate Plant Growth Responses

  1. Put 10 cress seeds into three different Petri dishes, each lined with moist filter paper

  2. Shine a light onto one of the dishes from above and two of the dishes from different directions

  3. Leave your cress seeds alone for one week until you can observe their responses
• Investigate the effect of gravity on plant growth

  1. Place four seedlings on damp cotton wool in a Petri dish, each with their roots pointing in a different direction

  2. Store the Petri dish vertically for a few days in the dark
• How to control variables

  • Use the same number of seeds in each dish
  • Use seeds that all come from the same packet
  • Keep your Petri dishes in a place where the temperature is stable (i.e. away from heat sources and draughts)
  • Use a measuring cylinder to add the same amount of water
  • Keep the distance between the bulb and dish the same