With the help of an activity prove that light is necessary for photosynthesis

cbse
cbse-class-7-science
nutrition-in-plants

#1

With the help of an activity prove that light is necessary for photosynthesis.

Answer:

  • Take some twigs of an aquatic plant like Hydrilla in beaker filled with water.
  • Invert a funnel over the twigs. Invert a test tube filled with water on the stem of the funnel.
  • Keep this set-up in sunlight for sometime.
  • Air bubbles (oxygen gas) will be seen coming out from the twigs. If this set-up is kept in the dark, no air bubbles will be seen.
    image
    This proves that light is necessary for photosynthesis.