Question

An inverted jar experiment is done to test the presence of ____ gas during photosynthesis.

Answer 1

Inverted jar experiment:

1. This experiment was done by Joseph Priestly for the first time.
2. He took a single bell jar and housed a burning candle and a rat inside that inverted bell jar. But he noticed that the flame burned out after a while, and the rat perished.
3. Then he placed a lit candle, a rat, and a green plant in the bell jar for the second time. But now he noticed that neither the candle got extinguished, nor the rat died.

Conclusion of the experiment:

1. Based on his findings, Priestley concluded that the candle and rat poisoned the air in the bell jar in the first scenario.
2. As the burning of flame produced CO₂, as well as the rat, exhaled the same gas. However, both burning and respiration in the rat required oxygen. So, oxygen was continuously consumed and more carbon dioxide was produced.
3. The plant, on the other hand, restored the air that had been contaminated by the candle and the rat in the second scenario.
4. The restoration was done in the way that CO₂ produced by candle flame and that released by the rat was used by the plant to synthesize food which released oxygen as a byproduct. The oxygen was used by the rat to survive and by burning flame.

Final Answer: An inverted jar experiment is done to test the presence of carbon dioxide gas during photosynthesis.