Plants and the Water Cycle Keeping Cool Interactive Slideshow

Keeping Cool… Have you ever exercised so much that you started to…

Sweat? Courtesy: Bill McKee, Earthdance.org Courtesy: Larry Imperiale

Sweating is the way that our bodies keep cool. If we did not have a way to release the heat our bodies generate, wed be in trouble. In fact, heat stroke is a very dangerous condition that occurs when your body is not able to keep cool. Did you know that plants also sweat?

Plants transpire gases from small openings in the surface of their leaves called stomates. These openings are emitting water vapor! This process of emitting water vapor through leaves is called transpiration. To keep from getting hot and dying, plants transpire water through their leaves! We sweat (or perspire), and plants transpire! Leaf as we see it Leaf under a microscope

What would happen if plants didnt transpire? Well…look what happens to a teapot on a stove. This red teapot is full of water. When water is heated, the energy (heat) moves from the stovetop, to the pot, to the water. The water gets hot, and turns into a vapor. Soon… youll see the steam coming from the spout! But… What happens to a tea pot when you put it on the stove without any water in it? Yep! It gets HOT! Dont try that one! Looks like this teapot got toasty! See the crack from the heat?

Just like full teapots, most green leaves are full of water. So when a stove heats up a full teapot, out comes the water vapor. The water absorbs the heat, which keeps the teapot from melting. And when the sun heats up a nice green leaf, out comes the water vapor! The water absorbs the heat, which keeps the leaf from dying!

And just like empty teapots, most brown leaves have no water. So when a stove heats up an empty teapot, the teapot starts to melt. And when the sun heats up dry leaves on plants, they start to get hot and die.

So, just like humans sweat to keep cool, plants on the earth do the same thing. Each of these trees in these pictures is transpiring water vapor (blowing off steam!) like a tea pot when they are warmed by the sun. Photos courtesy of the Rainforest Foundation

What happens to the water vapor after it leaves a plant? Heres a hint: Photo courtesy of the Rainforest Foundation Photo courtesy of Tom Warner

And what happens to the water when it leaves a cloud? Heres a hint: Photo courtesy of Tom Warner

And where does some of the rain go? Heres a hint:

And where does some of the root water go? Heres a hint: Hey! That picture looks familiar!

As the water travels through these different places, it forms a water cycle, because it keeps moving with no starting or stopping point. And all along the way, it keeps plants, animals, and people cool!

What would happen to the temperature of the earth if we didnt have plants and water to help it keep cool? Could we become a toasty tea pot? Photos courtesy of NASAs Earth Observatory