Clinton - Start Now!

Have you ever seen a picture of our planet, Earth, taken from outer space? It looks like a big ball with blue oceans, green and brown continents, covered in parts by swirls and puffs of airy white clouds. Everything on our planet is made up of elements, like oxygen and hydrogen, that keep us alive. Our healthand the health of all of the animals we share our world withdepends on the health of the planet. And the health of our planet depends on how we take care of it.

PART I: WATER

Most of the Earth is water. Were also full of watermore than half of your body is made of it. We need fresh, clean water to wash, cook our food, brush our teeth and of course to drink. But filling our cups is more complicated than it may first seem.

The amount of water on the planet hasnt changed for a very long time. The water the dinosaurs drank, swam in and played in is the same water that today falls from the sky as rain or snow and that later turns into the groundwater we drink. That means that the water we use today was around millions of years ago!

Most of Earths water is in our oceans. We dont drink ocean water because its salty and would eventually dehydrate us (and wed die). The water we drink comes from rivers, lakes, underground springs, even snowpack and glaciers. How do we make sure its safe for us to drink?

Clean, safe water means water that doesnt have anything in it that can make us sick. That includes bacteria, viruses or protozoa, all germs that can cause some deadly diseases. Clean, safe water means its free of harmful chemicals. We also need water that has no metals, like lead, that can hurt our brains or other parts of our bodies. Those are only a few examples of what is all too often found in water.

Dirty water (or getting enough clean water) has always been a challenge. This is partly because so many things dissolve in water and so many other things can be carried in it. Have you ever tried to dissolve something in water? Salt (like in the oceans) dissolves in water, where it seems to disappear, even if you can still taste it.

Still, lots of things dont dissolve in water. Have you ever seen a muddy river? Or a lake with trash floating in it? The mud and trash dont dissolve in water. Neither do germs, chemicals or metals. Drinking dirty or polluted water can make us sick and even kill us. All around the world today, one out of every ten people doesnt have access to clean water. In total, thats hundreds of millions of people across the world, including some who live in the United States.

How we have purifiedor cleanedwater has changed over time. Many thousands of years ago, people heated water over fire and filtered water through sand and gravel; in parts of the world today, this is still how some communities clean their water so it is safer to drink. Both the heat and the sand help kill some germs and remove dirt.

The ancient Romans were among the first plumbers! They built aqueductslarge-scale chutesto transport water from miles away to the one million people who lived in Rome. The pipes they used were made from lead. In the Romans language, Latin, plumbum meant lead. This is where we get the word plumbing. (We now know that lead in water is harmful to people of all ages, particularly to kids.) These ancient Roman plumbers cleaned the water to make it taste and smell better, though it still contained dangerous germs. They also had toilets (though not as advanced as ours today) and built a sewer system to remove waste (think poop). The pipes dumped the dirty wastewater into the Tiber River, removing the bad-smelling waste but polluting the river and putting germs into the water. In part because the Romans didnt know about germs or how to kill them, this imperfect system was the best they could come up with at the time.

Since Roman times, weve learned a lot about cleaning and transporting water. Still, even less than two hundred years ago, we didnt know that dirty water could make people sick.