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?
Joseph Priestley's experiment demonstrated the process of photosynthesis. When the candle was placed inside the sealed jar, it consumed the available oxygen and eventually went out due to lack of oxygen. However, when the plant was introduced inside the sealed jar along with the candle, the candle continued to burn.
Plants undergo photosynthesis, a process where they convert carbon dioxide and sunlight into oxygen and glucose. During photosynthesis, plants take in carbon dioxide from the air through small openings in their leaves called stomata. In the presence of sunlight, the plant uses the energy to break down carbon dioxide and release oxygen as a byproduct.
By placing the plant inside the sealed jar, Priestley ensured that the plant was absorbing carbon dioxide from the air and releasing oxygen. This allowed the candle to continue burning as the plant replenished the oxygen consumed by the flame. Hence, the combustion process of the candle could be sustained in the presence of the plant inside the sealed jar.