Plot

Evaporation, condensation, precipitation, advection, humidity, transpiration, and even evapotranspiration are introduced and taught in this video. We use live action FullDome videography to immerse the audience in the learning experience. This education module ends with a review set to a rap - the "Water Cycle Rap". Careful, you may find yourself humming the catchy tune well after you are back from the Science Center!—Kristan Gillespie

Water.

We drink it. Bathe in it. Swim in it. Play in it. But, have you ever really thought about water? For example, do you have any idea how old water is?

More than half of the Earths surface is covered with water. And, a lot of that water has been around pretty much as long as the Earth has. That makes water REALLY old.

It also means that the water you drink could be the same water an elephant drank 100 years ago or dinosaurs walked in even before that.

Can you say EWWWW?

[Pause]

Well, not so fast the Earth has a way to recycle water: use it, filter it and reuse it over and over again. Its called the Water Cycle. Do you want to learn about it?

[Pause]

Now, wait a second I need a little more excitement. This is science, people! Do you want to learn about the Water Cycle?

[Pause for exciting children screaming YES!]

The Water Cycle is a process that moves water from the Earth to the sky and back again. The whole process is driven by the sun. Solar radiation is the sun heating up the atmosphere.

When the sun heats up the Earth, surface water in lakes, streams, and oceans begin to change form. The water transforms from a liquid to gas from water to water vapor it evaporates.

Evaporation is the term scientists use to describe what happens when water turns to water vapor. When water evaporates, it becomes invisible because water vapor is a gas. You cant see it, smell it, or feel it.

And, there is always water vapor in the air. Evaporation happens constantly to keep the Earths climate in check. Once in the air, water vapor moves around the Earth. Advection is the sideways movement of water vapor in our atmosphere and its how we can recycle and reuse water from the oceans. Without advection, water from the oceans would just fall back into the oceans.

Evaporation also acts as a giant water filter. When water changes form from liquid to gas, it distills. It leaves chemicals, salt, pollution and all that stuff behind. Its how water from the ocean can fall on the land and not be salty AND why its not SO gross that an elephant may have drank your water 100 years ago. With evaporation, the water is filtered leaving the yucky stuff behind.

Plants also give off water. Its a process called transpiration. Plants get their water from the ground through their roots. When the sun heats up a plant, the plant releases water through its leaves as water vapor. Evaporation from the sun when added to plant transpiration is called evapotranspiration.

While you cannot see, smell or feel water vapor, we do have a way of measuring it. Humidity is the amount of water vapor in the air. You may have heard on the news: The humidity is high today. Humidity may increase during the growing season. Can you guess why?

During the growing season, humidity may increase because the amount of water vapor in the air increases. More plants are growing and, in turn, are transpiring, giving off water vapor.

So, what happens to all the water vapor in the air? Well, it rises. It travels up into the sky. The air above the Earth is cold so, when the water vapor gets cold enough, it changes form again. It gets denser. It condenses to liquid. Water vapor turns into tiny water droplets. This phase of the cycle is called condensation.

On a hot day, you may notice that the outside of a glass of water is wet. This water on the outside of the glass is water vapor that has gotten cold from the ice inside the glass and converted to water, making the outside of the glass wet.

Or, what about on a cold day when you can see your breath? When you breathe out, the warm air inside your body condenses when it meets the cold air outside. It changes to water, forming a small cloud in front of your mouth. Condensation.

When water vapor rises and meets the colder air above the Earth, it condenses to tiny water droplets and forms clouds. Clouds are made up of millions of water droplets. In fact, the average cloud weighs 40,000 tons!

Just like when you breathe out on a cold morning, you can see a small cloud in front of your face. The same concept is true on a larger scale. Water vapor meets cold air, condenses to form water droplets and millions of water droplets join together to form a cloud.

When enough water droplets join together, they start to get too heavy for the cloud. They have formed water drops and the water drops starts to fall. In other words, it starts to rain. When it starts to rain, we call this phase of the cycle precipitation.

Precipitation is when water begins its journey back to Earth. It may come back as rain, snow, sleet or ice depending on how cold it is when it starts to fall.

[Teacher: Opportunity for discussion on weather conditions and what makes snow versus sleet versus rain.]

As water travels back to Earth, it may fall into the oceans, or into lakes, streams or rivers. Sometimes, it falls on the land. Some water that falls on land runs off into lakes, streams, and rivers eventually finding its way back to the ocean. This water is called surface water. Other water that falls on land soaks deep into the ground, collecting in pockets called groundwater. Have you ever seen a water well? When someone drills a well, they are tapping into ground water.

This last phase of the cycle is called Collection.

At Collection, waters journey is complete well, until it starts over again! Considering how old water is, do you think it gets tired?

So, lets see how much youve learned. A quick pop-quiz you ready? When water turns into water vapor, this part of the cycle is called ______.

[Show word on dome give audience time to answer]

Water vapor then rises into the sky. When it meets cold air, it condenses to water droplets this part of the cycle is called ________.

[Show word on dome give audience time to answer]

It takes millions of water droplets to make a drop of water. Water drops are too heavy for the atmosphere to hold so it starts to rain, snow, sleet or ice. Its called _________.

[Show word on dome give audience time to answer]

When the water falls back to Earth, it gets ___________.

[Show word on dome give audience time to answer]

So, how OLD is water?

[pause for audience to answer]

How old?? Thats right water is as old as the Earth itself and, because of the Water Cycle, water can be used, filtered and recycled over and over again. Animals, plants and people depend on the Water Cycle for survival. It brings fresh water to the planet in rain, sleet, ice and snow.

[Start Water Cycle Rap]

(I rise to the sky from the sea below) (Then down to the ground as rain or snow)

Verse I

I represent the movement of water that's my purpose// Whether on, above, or below the earth's surface// In a continuous cycle, my work's never done// Cause I'm driven by energy from the sun//

I travel through the sea, through the air, through the ground// You could say that water really gets around// But in fact most waters just chillin' in the oceans// Only a small fraction is really in motion at any given time//

But yo that's the way it goes// When were studying the voyages of H2O// In the cycle water changes states at various places// The three states being ice, liquid, and water vapor//

But this cycle strays from the norm// Cause through the process, water still keeps the same structural form// While other cycles involve chemical change// Water may change states, but its structure stays the same//

Chorus

I rise to the sky from the sea below// Then down to the ground as rain or snow// I keep it moving, moving, cause I'm the water cycle// Moving, moving, cause I'm the water cycle//

Verse II

So when water transforms from liquid to gas// And rises up into the atmosphere, that's evaporation// A process made possible by energy from the sun// Also known as solar radiation//

And when this water vapor in the sky reforms// Into liquid water droplets, thats condensation// And when this water falls back down to the earth// As rain, snow, hail, or sleet, that's precipitation//

But plants have their own type of evaporation// Through their stomata, which is called transpiration// So collectively the term used for transpiration// Plus all other evaporation is evapotranspiration//

Two more terms to add to your collection:// The movement of water through the air is advection// And speaking of keeping it moving, understand// That runoff is water flowing across the land//

Chorus

Water Cycle rap created and produced by Rythme, Rhyme, Results, LLC www.educationalrap.com ©2010, All Rights Reserved