Describe briefly the contribution of Joseph Priestley. Joseph Priestley's experiments (1770):
GeneralClass 12AllAnswered 27 Mar 2026
Answer
- Mouse + candle in sealed bell jar → both died due to "vitiated air"
- Mint plant + mouse in sealed bell jar → mouse survived
- Mint plant alone for several days → "restored" the air
Conclusion: Plants release a substance (later identified as oxygen) that purifies air "fouled" by respiration and combustion.
Significance: First evidence that plants and animals have complementary gas exchange – plants produce O₂ consumed by animals, while animals produce CO₂ used by plants.
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