It's difficult to imagine that only about 1% of the water on our planet is drinkable. Most of it either isn't fresh, because if it's salt content, or it's frozen solid. Each drop undergoes changes as it methodically transforms from a solid to a liquid to a vapor. Ultimately, we have been sharing one giant glass of water with everything that has ever lived. Lucky for us it's still a renewable resource, since we can't live without it. But who knows for how much longer? Humans are affecting fresh water resources, too. Think about that the next time you drink your glass of water that was once a cloud or a drink for a dinosaur.