In 1774, the English chemist Joseph Priestley placed a lighted candle inside a large sealed jar. After a few minutes, the candle flame went out. When he placed a lighted candle and a plant inside the sealed jar, the candle continued to burn. Can you explain his results?1

Answer 1

Priestley's results demonstrated the process of photosynthesis, which occurs in plants. When the plant was placed inside the sealed jar with the candle, it continued to burn because the plant was taking in carbon dioxide released by the candle during combustion and converting it into oxygen through photosynthesis. This created a balanced environment where the candle could continue burning due to the presence of oxygen produced by the plant.

In the first scenario where only the candle was placed inside the sealed jar, the candle flame went out because it used up all the available oxygen in the jar for combustion. This experiment helped to illustrate the importance of plants in producing oxygen through photosynthesis, which is essential for supporting life on Earth.