A closer look
In the 1600s, Jan Baptist van Helmont wanted to know how plants grow. He weighed some dirt, planted a willow sapling, and watered it for five years. The tree gained 164 pounds, but the dirt only lost two ounces. He triumphantly concluded that wood is made entirely of water. He was entirely wrong—trees actually build themselves out of carbon dioxide pulled from the air. But ironically, van Helmont was also the very guy who coined the word "gas," completely missing that it was the answer to his own experiment.
