Question: In the 1640s, the Flemish chemist Jan Baptista van Helmont performed the classic experiment parap…
Show transcribed image text In the 1640s, the Flemish chemist Jan Baptista van Helmont performed the classic experiment paraphrased below: I filled a pot with 200 pounds of dirt that had been dried in an oven. Then I planted the stem of a willow tree and watered it with rainwater. At the beginning, the willow stem weighed 5 pounds. For 5 years, I watered the tree with either rainwater or distilled water whenever it was needed. The pot was large, and planted in the ground. I covered the pot with an iron plate. This had many holes, which allowed water through but not dust. In this way, I could be assured that possible dust accumulation over these 5 years did not significantly add to the weight of the dirt. After 5 years, the tree weighed 169 pounds, and about 3 ounces. I did not take into account the weight of the leaves that fell each autumn. At length, I again dried the dirt, which weighed only 2 ounces less than the initial 200 pounds. I concluded that the 164 pounds of wood, bark, and squareroots, arose out of water only. In what way was Van Helmonfs conclusion incorrect? He did not account for the role of atmospheric carbon dioxide in photosynthesis. He should have included the fallen leaves in his calculation. His conclusion would have been different if he had thoroughly dried the wood before determining the final mass of the tree. He should have kept careful measurements of the water he used.
In the 1640s, the Flemish chemist Jan Baptista van Helmont performed the classic experiment paraphrased below: I filled a pot with 200 pounds of dirt that had been dried in an oven. Then I planted the stem of a willow tree and watered it with rainwater. At the beginning, the willow stem weighed 5 pounds. For 5 years, I watered the tree with either rainwater or distilled water whenever it was needed. The pot was large, and planted in the ground. I covered the pot with an iron plate. This had many holes, which allowed water through but not dust. In this way, I could be assured that possible dust accumulation over these 5 years did not significantly add to the weight of the dirt. After 5 years, the tree weighed 169 pounds, and about 3 ounces. I did not take into account the weight of the leaves that fell each autumn. At length, I again dried the dirt, which weighed only 2 ounces less than the initial 200 pounds. I concluded that the 164 pounds of wood, bark, and squareroots, arose out of water only. In what way was Van Helmonfs conclusion incorrect? He did not account for the role of atmospheric carbon dioxide in photosynthesis. He should have included the fallen leaves in his calculation. His conclusion would have been different if he had thoroughly dried the wood before determining the final mass of the tree. He should have kept careful measurements of the water he used.
