About 200 years ago, Jan Baptista van Helmont tried to determine the source of raw materials for plant growth. To do so, he planted a young tree weighing 5 pounds in a barrel filled with 200 pounds of soil. He watered the tree regularly. After 5 years, he again weighed the tree and the soil. At that time the tree weighed 169 pounds, 3 ounces, and the soil weighed 199 pounds, 14 ounces. Because the tree’s weight had increased so much, and the soil’s weight had remained about the same, he concluded that the tree gained weight as a result of the water he had added to the barrel. Analyze his conclusion in terms of the information you have learned from this chapter.
