Jan Baptista van Helmont was the first to try and scientifically address the question of where plants got their
food. His experiment, which was conducted
in the 1600's, tested the idea that all of a plant's nutrients came
from the soil. He planted a willow tree
seedling in a pot of soil after weighing both the tree and the soil
.
After
5
years, the tree had gained 74 kilograms
(164 pounds), but the soil had lost only 57 grams (2 ounces)
. He
wrongly concluded that the mass
gained only came from the water and soil he provided.
Why was Jan Baptista van Helmont's conclusion incorrect? Explain how the willow-tree seedlings got their
food.