I love science. So now that fall is here and school has started again, I want to share one of my favorite cool science facts. I was floored in elementary school the first time I learned that we drink the same water as the dinosaurs did. What?!? How can that be? Well, let me give you a short lesson in "The Water Cycle." Cue cool music...
Water has been on the earth for millions of years and water is a pretty durable thing. It travels through cycles of changing states and constant movement. Most water molecules are pretty durable, too, during all of this change, and continue on, basically recycling themselves over and over. Water molecules depend on energy from the sun to change states. When the temperature of the water is moderate it stays in its liquid state. Liquid water covers about 70% of the earth's surface in the form of oceans, lakes, rivers, streams, and ponds. When the temperature changes, so does the state of the water. When the temperature cools to 32 degrees water turns to a solid - ice. As the temperature heats to over 212 degrees it turns to a gas - vapor. I bet you didn't know water was so talented, did you?
Of course, water is also a big traveler. It is always on the move. Let's use a puddle as an example of water's journey. The water molecules in the puddle are in their liquid state. As the sun beats down on the puddle, the temperature of the water rises and the molecules begin to change into vapor, which is lighter than air and begins to rise. As more and more vapor rises and the puddle slowly shrinks, it is known as evaporation. So now the water vapor has risen very high in the sky. The temperature is much cooler at this altitude and so the vapor begins to cool, too. As it changes back into its liquid state, the vapor joins with other vapors, creating larger drops or condensation. You can see this on a window as well when the air inside the room is colder than the air outside and condensation forms on the outside of the window. As the vapors condense together and create larger and heavier drops, they will fall back down to earth. Condensation is constantly being blown around by winds. So where the rain drop eventually falls may be many hundreds or thousands of miles from where that water molecule started out in its puddle. Depending on the temperature of the air around the drops, they will either fall as liquid rain or in cooler temperatures as snow, hail, or sleet. Once it is back down to the earth's surface, the cycle of evaporation, condensation, and precipitation will start all over again, as will water's change from liquid to gas to solid.
It is so interesting to think that water covers 70% of the earth and humans are also made up of about 70% water. Even though there is so much water on the surface of the earth, underground, and in the air, only 1% of the earth's water is potable (safe to drink). The rest is either too dirty or too salty for us to drink. That is an amazing figure, and water flows through a constant amazing cycle. Which brings us back to the dinosaurs. Think of the possibilities. The glass of water you just drank might have also been drunk by a thirsty stegosaurus or even Albert Einstein or it might have sat on top of Mt. Everest as snow or was part of the iceberg that rammed the Titanic. Pretty mind boggling, huh?
No comments:
Post a Comment