An early experiment by Van Helmont (1600s) describes how he "grew a tree in a large pot and found that after five years, the amount of soil in the pot had not changed. He concluded that the increase in weight was due to the addition of water." At that time, the compounds in the air had not yet been identified. Today, you know that he only discovered half the story. Which additional experiment would provide evidence for the rest of the story?

Question

Quizplus · Accepted Answer

Van Helmont's experiment overlooked the role of carbon dioxide from the air in plant growth. Choices A, B, and C each address aspects of how plants gain mass through processes other than just water intake: A) highlights the discrepancy in mass gain, B) points out carbon's role, and C) suggests tracing carbon from the air to the tree. D) is incorrect because Van Helmont's experiment already considered soil nutrients and found no significant change, indicating that the mass gain was not primarily from soil nutrients.

An Early Experiment by Van Helmont (1600s) Describes How He