Write the experimental procedure to prove that oxygen is produced during photo-synthesis in the presence of light.

Explanation

Reasons for placing the test tube upside down on funnel:
1) To count the number of bubbles coming out of the hydrilla twigs per minute during photosyn- thesis.
2) To collect sufficient amount of oxygen at the end of the test tube so that it can be tested with glowing splinter.
3) Amount of oxygen produced in the test tube can be measured by the displacement of water within the test tube.