Question

Who found that oxygen is released in the hydrilla plant when it is kept in sunlight?

Answer 1

INTRODUCTION:The end products of photosynthesis are Oxygen(O2),water and starch.So one of the end products is oxygen ,which is proved by this experiment.



AIM:To prove oxygen is evovled during photosynthesis in the presence of sunlight.

APPARATUS:Beaker,water,test tube,hydrilla plant twigs,funnel and sunlight

PRECAUTION:-Setup should be kept in sunlight
-The level of water in the beaker should be over the level of stem of the inverted funnel
-While removing testtube ,place your thumb near mouth of testtube to prevent escape of gas(oxygen) evolved and remove gently.

PROCEDURE:1)Place hydrilla plant twigs in a short stemmed funnel and keep it in a beaker containing water.
2)Invert a test tube full of water over the stem of the funnel
3)Place the apparatus in the sun for at least 2-3 hours.
4)After sometime observe the apparatus

OBSERVATION:1)Gas bubbles i,e.,oxygen is produced at the end of test tube and remove the test tube gently.
2)Test the gas in the testtube by inserting a glowing incense stick which would burst into flames.
3)This shows the presence of oxygen.

RESULT:By this experiment, we proved that oxygen is produced during photosynthesis in the presence of sunlight.

Answer 2

Jan Ingenhousz

Jan Ingenhousz through his experiments showed that sunlight is essential for the plant process.In another experiment,with an aquatic plant(Hydrilla)he showed that in bright sunlight ,small bubbles were formed around the green parts of plant while in dark,no bubbles were formed. He identified those bubbles to be oxygen.