Question

Jane filled one transparent bottle and one brown bottle of the same capacity with pond water. She kept the first bottle in sunlight and the second in dark. After one hour she calculated the amount of oxygen present in both the bottles. What will be her observation?

Answer 1

In the transparent bottle, the algae and small plants present in the pond water utilize oxygen for photosynthesis. In the brown bottle, due to darkness they cannot utilize oxygen dissolved in the water. Therefore, oxygen in the transparent bottle is lesser than that in the brown bottle.
In both the bottles the algae and small plants present in the pond water carry out photosynthesis. Therefore, the amount of oxygen in both the bottles remains the same.
In the transparent bottle, the algae and small plants present in the pond water release oxygen during photosynthesis, while in the dark bottle, photosynthesis doesn’t occur due to darkness. Therefore, oxygen in the transparent bottle is more than that in the dark bottle.