Johann Baptista van Helmont coined the term "gas" in 1620 to describe substances like air. His idea for the term came from the Flemish word for chaos. He once conducted a famous experiment in which he planted a willow tree in a container filled with a known mass of soil. For several years he only added water as the tree grew to a significant size. After cutting the tree, he found that the total mass of the soil was essentially the same, and incorrectly assumed that most of the mass of the tree came from water. It was later found to be largely from the carbon dioxide absorbed from air. He was also the first to show that chemically produced gases were different from air.