How can you prove light is needed for photosynthesis experimentally?
Answers
The process photosynthesis I'd present in plants
These process occur in present of sunlight
Light is observed by leaves and then food forming in plants
Procedure
Detach the leaves of a potted plant.
Cut a simple shape from a piece of thick cardboard of aluminum foil and fix it onto the upper and lower surface of some of the leaves using paper clips, such that part of the leaf is covered whilst other parts are not covered.
Put the plant in sunlight for three (3) hours.
Remove the cover and test the leaf for the presence of starch.
Observation
The areas covered by the thick cardboard or aluminium foil tested negative for the the presence of starch but the area exposed to the sunlight tested positive for the presence of starch.
The presence of starch in the uncovered portion and it's absence in the covered portion shows that sunlight is necessary for the formation of starch.
As starch is formed by photosynthesis, sunlight must be necessary do photosynthesis.