Water is the single most important component for life on Earth. 70% of the human body is made of water. If you place your ear against a person who is jumping up and down, you might even be able to hear some of that water sloshing about. Isn't science fascinating? In order to live, a human must drink at least two gallons of what every day. Fortunately, American scientists armed with this knowledge were able to invent one of the most important devices we have in today's society.