Blue Planet
Pictures taken of the earth from outer space show that our planet looks like a beautiful, blue ball! Why? Because 72 percent of the earth's surface is covered by water! That's a lot!
Most of that water, about 97 percent, is saltwater found in oceans and seas. That means that only 3 percent is fresh water. Here's an easy way to think of these percentages: If there were 100 glasses of water representing the earth's water, 97 of them would be filled with saltwater and only 3 glasses would contain fresh water! This is why water is a very precious resource.
| Fun Fact: Most of the earth's fresh water is frozen in icecaps and glaciers! |
Water, Water Everywhere
It may be hard to believe, but water is the main ingredient of the human body! Can you guess how much water the human body is made of?
Water is found in your skin, bones, muscles, organs and body fluids. Did you know that a little over half of your blood is liquid? This portion of your blood is also called plasma. About 90 percent of blood plasma is water!
Our bodies use water to digest food, deliver nutrients to our cells, clear waste, regulate our temperature, and carry hormones and disease-fighting cells to different body parts. It is important for you to drink six to eight glasses of fresh water every day to keep your body healthy and strong!
| Fun Fact: When you get hot your body sweats. This helps you cool off, but it also causes your body to lose water. This is why you should remember to drink extra water during warm weather or while exercising. |
Just
like you, animals need water to survive. If you have pets, you probably
already know the importance of water for animals. Your dogs, cats and birds
drink water when they are thirsty. Your fish make their home in a water-filled
aquarium. If you live on a farm, you make sure your animals have access
to a fresh water source. Wild animals need water too. Crocodiles live in
damp, muddy swamps. Camels store water in their humps. Sea otters love to
play in water. Can you think of other ways that animals in the wild use
water? | Fun Fact: About 85 percent of all living creatures spend their entire lives in water! |
Water
is important to plants too. Plants usually absorb water through their roots.
They also collect water on their branches and leaves when it rains. Sap
in trees contains water and it is used to transport nutrients within the
plant. Cacti store water for later use. Many plants live underwater in lakes,
rivers and oceans. You may have seen lily pads which are beautiful plants
that live in ponds. Water shows us its power and beauty in the oceans, waterfalls, geysers, lakes, rivers and streams. All living things need water to survive. Water is an important part of life, the ecosystem, and our planet. Protecting this resource is very important.
| FUN FACT: Water can be found in the food we eat, too. A tomato contains 95% water. An apple has 85% and just over half of a hotdog is made up of water. |
Special Agent H2O
Water is made up of the element hydrogen (H) and the element oxygen (O). Elements are made up of tiny particles called atoms that are too small to see with our eyes. A water molecule consists of two hydrogen atoms and one oxygen atom, and is often referred to by its chemical name, H2O.
| DID YOU KNOW? Water molecules like to stick together! They bind to themselves and other substances like plant tissues and soil. When one water molecule sticks to something, it pulls other molecules right along with it. This is why water wets so many materials and why it easily makes it way up the roots of plants! |
Water is an amazing substance. It can do so many things that it almost seems magical!
Ice is water in solid form. Solid water is great for ice-skating and ice
hockey. On hot summer days, water in the form of ice cubes cools our drinks.
In cold weather when the temperature reaches 32 degrees Fahrenheit or below,
water falls to the earth as hail, sleet or snow. | Fun Fact: When water turns to ice it floats. This is why fish can live in lakes during the winter because the water underneath the frozen surface is still liquid. If water wasn't lighter in its solid state (ice) than in its liquid state, lakes and other bodies of water would freeze into solid blocks of ice. |
Water can take the form of a gas. We call this water vapor or steam. You
have probably seen water turn from liquid to gas many times in your kitchen.
When water is boiled on your stove it is easy to see the steam rising into
the air. You may also have noticed that the amount of liquid in the pot
decreases over time. Is the water disappearing? No, it is evaporating as
steam into the atmosphere. | Fun Fact: Water left in an open container will eventually evaporate and become water vapor even if it's not heated! |
Water can also take the form of a liquid. In fact, water is the most common
liquid on earth! We see this form of water in our environment every day.
We drink it, bathe in it, work with it and play in it! Our oceans, lakes,
rivers and streams are precious natural resources from the earth! A World Full of Uses
Think of all the ways that we enjoy water! A glass of water tastes great
when we're thirsty, but there are many other uses for water. Water is used
in food preparation. We also use water for cleaning our bodies, clothes,
houses, cars and pets. When it's warm outside, water cools us off while
we are swimming and boating. Did you know that water is an important ingredient
in the manufacturing of toys, crafts and paper? It is also used in farming
and agriculture, building, transportation, hydroelectric energy and other
businesses. Industries use hundreds of billions of gallons of water each
day. What Goes Around Comes Around
Water plays an important role in weather too! We can see why this is true
by looking at the water cycle. The water cycle begins when the sun warms
the waters of the oceans, lakes, rivers and streams. The water evaporates
and rises into the air in the form of water vapor. Clouds form and continue
to hold more and more water until they are full. At this point, the water falls back upon the earth as rain, sleet, snow or hail. The water travels down mountains and valleys or through streets and storm drains and eventually returns to the streams, rivers, lakes or oceans. Then the cycle is complete...and ready to begin again!
| Fun Fact: Fog is a cloud that rests on the ground! If you take a walk when its foggy you can feel the water droplets in the air. |
A World-Class Recipe
Nature is like an amazing chef who makes weather using a variety of recipes. Nature combines many different ingredients in order to create everything from sunny skies to windy days to thundering storms. How many types of weather conditions can you think of? Differences in air pressure, heat, humidity and world-wide air currents all effect our weather. Weather varies from day to day and throughout the changing seasons.
The
sun is the earth's sole source of heat energy. It is responsible for many
things, including the water cycle, ocean currents and winds. The sun can heat land more quickly than it heats the oceans and seas. However, once water warms up, it retains its heat longer than does soil and rock. These facts can help us understand certain weather patterns.
For example, by late spring the land is warmer than the oceans. The landmass heats the air around it. Warm air rises. As air rises, it expands making it less dense and creating low-pressure. At the same time, the air over the ocean is cooler. Because cool air is denser and heavier, it falls. This dense air creates high-pressure. The low-pressure area over the land pulls in the air from the high-pressure area over the ocean.
During
the fall season, it is just the opposite. The land is cooler than the ocean
and, therefore, the high-pressure area is over the land. Can you guess what
happens then? The low-pressure area over the ocean causes the air to flow
from the cooler land toward the warmer waters. The air pressure combined
with the winds are two important factors in the world's weather. | Fun Fact: In 1643, Torricelli, a student of the famous scientist Galileo, invented the instrument called a barometer. |
What is the wind? It's air in motion! One type of wind is created by the
movement of air flowing from an area of high-pressure into an area of low-pressure.
Changes
in the air's pressure and temperature also cause changes in the air's humidity.
Humidity is the amount of water vapor or moisture in the air. Moving air
gains and loses moisture too. The point where a cold air mass and a warm air mass meet is called a front. The warm front arrives first and usually signals the approaching cold front.
This
is because the warm and moist tropical air rides on top of the cold air.
At this point, the weather can change rapidly. These changes are shown on
the barometer, thermometer, hygrometer and anemometer.
Weather or Not
Clouds play a big part in nature's weather machine! Clouds form when air
cools and invisible water vapor in the atmosphere condenses into visible
water droplets or ice crystals. Clouds have different names depending on
their shape, form and altitude. The type of cloud, its temperature and height
are some of the factors that determine whether or not it rains, sleets,
snows or hails. | Fun Fact: Luke Howard was the first person to develop a cloud classification system. He did this in 1802 and we still use his cloud names today. Howard is sometimes called the "Godfather of the Clouds." |
Meteorologists, the people who study the weather, look at the height or altitude of where specific clouds form. They place clouds at one of three levels in the sky: low, medium and high. Clouds that bring rain, sleet, snow or hail are in the low and medium range. These clouds start below 6,000 feet off the ground and can go as high as 16,000 feet.
Millions of tiny water droplets are inside a rain cloud. If the cloud is
high and very cold, the water droplets freeze to form ice crystals which
join together to form snowflakes. The temperature of the air must be at
freezing or below to form snow, sleet or hail. This thermometer is at the
freezing point. Not all the snowflakes formed in clouds end up as snow on the ground. Sometimes as snowflakes fall through a cloud, they meet warmer air. When this happens, the snowflakes melt into raindrops.
| Fun Fact: Every snowflake has six points but each one looks totally different! |
Where Does Your Water Flow?
Only a small portion of the earth's water can be used for drinking. Most is salty sea water that we cannot drink. Other waters are polluted and unhealthy for us to use.
| Fun Fact: Americans use 90 billion gallons of fresh water each day! |
What
are some of the causes of water pollution? Water can become polluted through
garbage in landfills. Water runs through the garbage and waste and becomes
contaminated. Unless it is properly contained, this watery substance, called
leachate, can find its way into rivers, lakes or oceans. 
Water
can become polluted from dumping toxic substances. Chemical waste is sometimes
dumped into oceans, rivers, lakes and streams. For example, if people use
toxic soaps to wash their cars, the soap can run into the gutters and out
to a local body of water. Another form of pollution happens when large oil
tankers at sea cause oil spills. The oil pollutes the water and harms sea
life. Oil also pollutes our oceans when people dispose of their used motor
oil incorrectly. Most gas stations and auto repair shops will accept used
motor oil for recycling. It is important to dispose of all toxic substances
properly. Air pollution also pollutes our water. Water evaporates into the air and becomes water vapor or gas. If the air is polluted the water vapor will also be unclean. This polluted water vapor will eventually fall back to earth as rain, hail, snow or sleet. It ends up in a body of water or falls onto the land.
Human beings are directly responsible for the pollution of the oceans, rivers, lakes and streams. It's important to conserve water and to do our best to keep it clean for our health and the well-being of all life on earth.
It's Cool to Conserve
Let your parents or guardians know that you want to do your part to save
water. You can also talk with your friends at school and tell them what
steps you are taking to help conserve water. Check out Misty's Water Conservation
Project and see how fun saving water can be. You can find it in Misty's
Cool Projects at www.ecopals.com.Here are some ideas to get you started:
- Take short showers.
- Turn off the water when you brush your teeth.
- Check your house or school for water leaks.
- When taking baths, fill the tub only halfway.
- Make sure you don't leave faucets dripping.
- Use warm or cold water to wash your clothes, instead of hot water.
- Sweep your driveway, instead of hosing it down.
- Join in local activities that clean and protect beaches and rivers.
- Use non-toxic, earth-friendly products at home.
- Support organizations that are working to keep our water clean.
Dive into these really cool books and websites to learn more about water.
Books:
Holmes, Anita. I Can Save the Earth, (New York: Julian Messner/Simon and Schuster, 1993).
Morgan, Sally, Weather, (Sydney, San Francisco: The Nature Company Discoveries Library, Time Life Books, Weldon Owen Group of Companies, 1996).
Ruiz, Andres Llamas. Rain, (New York: Sterling Publishing Company, Inc., 1996).
Savan, Beth. Earth Watch: Earthcycles and Ecosystems, (Reading: Addison-Wesley Publishing Company, 1991).
Sheehan, Kathryn and Mary Waidner. Earth Child 2000, (Tulsa, San Francisco: Council Oaks Books, 1998).
Taylor, Barbara. Weather and Climate, (New York: Kingfisher, 1993).
The Nature Company Discoveries Library, Time-Life Books. Weather (Sydney, San Francisco: US Weldon Owen Inc., Weldon Owen Pty Limited, 1996).
Websites:
Visit the American Rivers website at:
http://www.amrivers.org/kids-save.html
Stop by and Dan's Wild Wild Weather Page at:
http://www.whnt19.com/kidwx
For loads of great information and fun, check out the United States Government Survey (USGS) site at:
http://wwwga.usgs.gov/edu