on the Planet Earth
Objectives and Indicators for this Unit :
. INTERACTIONS OF HYDROSPHERE AND ATMOSPHERE
INDICATOR
- 1. Cite evidence to explain the relationship between the hydrosphere and atmosphere.
OBJECTIVES
- Describe the composition of the atmosphere and hydrosphere.
- Recognize and describe the water cycle as the distribution and circulation of Earth's water through the glaciers, surface water, groundwater, oceans, andatmosphere.
- Identify and describe how the temperature and precipitation in a geographic area are affected by surface features and changes in atmospheric and oceancontent.
- Relative location of mountains
- Volcanic eruptions
- Proximity (closeness) to large bodies of water
- Heat energy of ocean currents
INDICATOR
- 2. Recognize and describe the various factors that affect climate.
OBJECTIVES
- Identify and describe how the temperature and precipitation of an area are affected by surface and ocean features.
- Relative location of mountains
- Proximity (closeness) to large bodies of water
- Warm and cold ocean currents
- Recognize and describe the global effects of volcanic eruptions, greenhouse gases, and El Nino.
INDICATOR
OBJECTIVES
- Identify and describe weather patterns associated with high and low pressuresystems and the four frontal systems using appropriate data displays includingweather maps.
- Identify and describe the atmospheric and hydrospheric conditions associated with the formation and development of hurricanes, tornadoes, andthunderstorms.
- Identify and describe how various tools are used to collect weather data and forecast weather conditions.
- Barometer
- Thermometer
- Anemometer
- Psychrometer
The Earth's atmosphere is a thin layer of gases that surrounds the Earth. It composed of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and trace amounts of other gases. This thin gaseous layer insulates the Earth from extreme temperatures; it keeps heat inside the atmosphere and it also blocks the Earth from much of the Sun's incoming ultraviolet radiation.
The Earth's atmosphere is about 300 miles (480 km) thick, but most of the atmosphere (about 80%) is within 10 miles (16 km) of the surface of the Earth. There is no exact place where the atmosphere ends; it just gets thinner and thinner, until it merges with outer space.
Air Pressure:
At sea level, the air pressure is about 14.7 pounds per square inch. As your altitude increases (for example, if you climb a mountain), the air pressure decreases. At an altitude of 10,000 feet, the air pressure is 10 pound per square inch (and there is less oxygen to breathe).
The Layers of the Atmosphere:
Thermosphere: The thermosphere is a thermal classification of the atmosphere. In the thermosphere, temperature increases with altitude. The thermosphere includes the exosphere and part of the ionosphere.
•Exosphere: The exosphere is the outermost layer of the Earth's atmosphere. The exosphere goes from about 400 miles (640 km) high to about 800 miles (1,280 km). The lower boundary of the exosphere is called the critical level of escape, where atmospheric pressure is very low (the gas atoms are very widely spaced) and the temperature is very low.
•Ionosphere: The ionosphere starts at about 43-50 miles (70-80 km) high and continues for hundreds of miles (about 400 miles = 640 km). It contains many ions and free electrons (plasma). The ions are created when sunlight hits atoms and tears off some electrons. Auroras occur in the ionosphere.
•Mesosphere: The mesosphere is characterized by temperatures that quickly decrease as height increases. The mesosphere extends from between 31 and 50 miles (17 to 80 kilometers) above the earth's surface.
•Stratosphere: The stratosphere is characterized by a slight temperature increase with altitude and the absence of clouds. The stratosphere extends between 11 and 31 miles (17 to 50 kilometers) above the earth's surface. The earth's ozone layer is located in the stratosphere. Ozone, a form of oxygen, is crucial to our survival; this layer absorbs a lot of ultraviolet solar energy. Only the highest clouds (cirrus, cirrostratus, and cirrocumulus) are in the lower stratosphere.
•Tropopause: The tropopause is the boundary zone (or transition layer) between the troposphere and the stratosphere. The tropopause is characterized by little or no change in temperature altitude increases.
•Troposphere: The troposphere is the lowest region in the Earth's (or any planet's) atmosphere. On the Earth, it goes from ground (or water) level up to about 11 miles (17 kilometers) high. The weather and clouds occur in the troposphere. In the troposphere, the temperature generally decreases as altitude increases.
Formation of the Atmosphere:
The Earth's atmosphere was formed by planetary degassing, a process in which gases like carbon dioxide, water vapor, sulphur dioxide and nitrogen were released from the interior of the Earth from volcanoes and other processes. Life forms on Earth have modified the composition of the atmosphere since their evolution.
Assignment= Please copy into your journal and complete this graphic organizer about the "Atmosphere"
The EARTH’s atmosphere is made up of several layers. The layer closest to the earth is called the troposphere. This is where most of the water vapor is. Most weather takes place in this layer. The air temperature decreases as you go up from the bottom to the top of the troposphere.
Assignment=Please go on line and learn about the the details @ Troposphere layer of the atmosphere. Put your notes in your journal
ASSIGNMENT= Please click the website below and play the game.
Then 1) Explain in your journal exactly what happened. and
2) Explain in your journal why you think it happened in the way it did?
What elements are in the air and space?
Elevator to space activity
Do you know that YOU can forecast the weather on your own? Use your sense of sight as you look up in
to the sky. What color is it? Is it blue or gray? Is the sun shining? What kind of clouds do you see?
to the sky. What color is it? Is it blue or gray? Is the sun shining? What kind of clouds do you see?
Clouds can tell you a lot about the weather. Thin, wispy, cirrus clouds point in the direction the wind is blowing. They predict fair weather for now and a while from now.
•If the sky is full of low, gray, nimbostratus clouds, you can count on light, but steady, precipitation.
Maybe you see altocumulus clouds that look like sheep's wool. If you do, you can predict that a cold front is coming. A thunderstorm may be on its way.
Cloud Type Graphic Organizer
Assignment=Please copy this graphic organizer and complete it from the readings about clouds.
Assignment= Please copy in your journal and complete this 3 way venn diagram from the 3 types of clouds that you read about in the paragraphs above
Play this cloud matching game
Explain what a hydrosphere is?
•In a 3-5 sentence paragraph
in your journal
in your journal
Hurricanes are like giant engines that use warm, moist air as fuel. That is why they form only over warm ocean waters near the equator. The warm, moist air over the ocean rises upward from near the surface. Because this air moves up and away from the surface, there is less air left near the surface. Another way to say the same thing is that the warm air rises, causing an area of lower air pressure below.
ASSIGNMENT=Summarize what causes a hurricane in 2-4 sentences and put it in your journal.
•The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface.
• A tropical cyclone or hurricane has so many cumulonimbus clouds Together, they form huge, circular bands.
•As the hurricane rotates faster and faster, an eye forms in the center. It is very calm and clear in the eye, with very low air pressure. Higher pressure air from above flows down into the eye.
A hurricane is a powerful, rotating storm that forms over warm oceans near the Equator. Another name for a hurricane is a tropical cyclone. Hurricanes have strong, rotating winds (at least 74 miles per hour or 119 kilometers per hour), a huge amount of rain, low air pressure, thunder and lightning. The cyclonic winds of a hurricane rotate in a counterclockwise direction around a central, calm eye.If this type of storm forms in the western Pacific Ocean, it is called a typhoon.
Hurricanes often travel from the ocean to the coast and on to land, where the wind, rain, and huge waves can cause extensive destruction.
Generally, when a hurricane moves over land (or over cold ocean waters) the storm begins to weaken and quickly dies down because the storm is fueled by warm water.
On average, there are about 100 tropical cyclones worldwide each year; 12 of these form in the Atlantic Ocean, 15 form in the eastern Pacfic Ocean and the rest are in other areas.
Hurricane season is the time when most Atlantic Ocean hurricanes occur; it is from June 1 until November 30. In the eastern Pacific Ocean, hurricane season is from May 15 until November 30.
Hurricanes
Hurricanes rotate in a counterclockwise direction. |
Hurricanes often travel from the ocean to the coast and on to land, where the wind, rain, and huge waves can cause extensive destruction.
Generally, when a hurricane moves over land (or over cold ocean waters) the storm begins to weaken and quickly dies down because the storm is fueled by warm water.
On average, there are about 100 tropical cyclones worldwide each year; 12 of these form in the Atlantic Ocean, 15 form in the eastern Pacfic Ocean and the rest are in other areas.
Hurricane season is the time when most Atlantic Ocean hurricanes occur; it is from June 1 until November 30. In the eastern Pacific Ocean, hurricane season is from May 15 until November 30.
Assignment= Please copy into your journal and complete this graphic organizer about hurricanes
Forming Clouds
Forming Clouds
Air from surrounding areas with higher air pressure pushes in to the low pressure area. Then that “new” air becomes warm and moist and rises, too. As the warm air continues to rise, the surrounding air swirls in to take its place. As the warmed, moist air rises and cools off, the water in the air forms clouds.
Assignment= Please copy into your journal and complete this graphic organizer about "Forming Clouds
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As you read the story below, think about how you would answer these questions.
Tornadoes on the Soccer Field! | ||||||||||
In a flurry of flying lawn chairs, wet blankets and soccer bags, parents grabbed their kids and ran in different directions. My family’s car was several fields away and there was no good shelter nearby and no time to think. We ran to the nearest drainage ditch.ASSIGNMENT=Please click the website and play the game.
http://www.windows2universe.org/art_and_music/cloud_art/clouds_in_art.html
Assignment= Please copy into your journal and complete this graphic organizer about "The Biggest Forces in Nature and The Damage They Cause"
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Assignment=COPY AND ANSWER IN YOUR JOURNAL
As you read the story below, think about how you would answer these questions.
- How would you feel if you were in this weather event?
- Would you do anything differently to make sure you stay safe?
Surviving Hurricane Carla
Story by Carol Park
I was 10 years old in September of 1961 when a storm began to form out in the Gulf of Mexico. The storm grew into a Category 5 hurricane. They named it Carla.We lived in a Houston neighborhood with small homes and ditches running alongside the streets. In those days, people did not evacuate to flee storms, nor did they board up their homes; they stayed put. My parents decided to throw a hurricane party for the adults and while they were inside playing cards, the kids were outside running wild.
It was eerie playing outdoors while the clouds grew dark and swirly. I remember it looked like night, in the middle of the afternoon. It began to rain. The wind began to howl and something in the air made us feel wild and free. We waded in the ditches trying to catch crawfish but when the lightning began to strike dangerously close to the crackle of thunder, my mother called us in. We were drenched. Despite the edge of fear in the air, it was exciting and we all remained in high spirits. I was mesmerized by what the storm was doing outside.I remember watching out of our picture window. The wind caused the trees and bushes to bend over in funny ways I’d never seen before. The power lines were swinging around. The ditches flooded, then the roads, and then the yards. I recall seeing tiny, brightly colored frogs plastered on the window I was looking through. Was it raining frogs? Or, were the frogs just looking for an escape from the soaked ground?
After some time, everything became still and silent. Even the birds were quiet. The winds calmed, the clouds parted and the sun appeared. The eye of the hurricane was over Houston! We ran outside and I looked up to see blue sky. After about an hour, the clouds darkened and the wind and rain returned. We went back inside and watched the second half of the storm.We went to bed with the rain beating on the roof and the wind howling. The next morning we awoke to a different world. The sun was shining and the birds were chirping. Tree limbs were down everywhere and the roads and yards had become a giant lake. Hurricane Carla had left her mark on the landscape and our lives. The best part was that everyone was safe and the kids got a bonus 3 days off from school!
FACTS: Hurricane Carla
- September 9 -12, 1961
- The strongest storm to hit the Gulf Coast since the storm of 1919 (Galveston)
- Max sustained winds: over 150 mph
- Rainfall: 10-16 inches over 3 days
- Storm surge: tides reported to be 10’-15’ above normal
- Lives lost: 43
- A more detailed description of the storm
Assignment= Look up on ther internet, research and take notes. Then write a 3-5 sentence paragraph about each one.
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1) Explain about the worst hurricane in history.
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•2) Explain about the worst earthquake in history.
3) Explain about the worst tornado in history. •Fire and Dust A Poem by Trista L. Pollard
•A force of thousands,
Thrust toward the airTiny particles,
too small to stare
Each unique and full of text
Of the Earth's anger, fire, and vex
Thrust toward the airTiny particles,
too small to stare
Each unique and full of text
Of the Earth's anger, fire, and vex
Volcanoes
If you look at a volcano far away, it looks like a mountain. The main difference is a mountain is made of solid earth. A volcano opens from its top all the way down to a pool of hot, molten rock. This molten rock is stored in a cavern. The cavern is surrounded by earth except on its top.
The molten rock sits below the surface. It usually cannot be seen unless someone is looking down into the hole from the top. On occasion, it can be seen leaking out of the hole at the top. For this to happen there has to be an eruption!
When a volcano is not erupting, it is in what is called a �dormant� state. You can usually tell when a volcano is going to explode. It starts with gases from the volcano. These gases and rock shoot up through the opening in small amounts. When you see the smoke coming from the top, it usually means that the volcano is going to erupt.
When a volcano erupts, the rock and volcanic gases do one of two things. They either spill over the edge of the volcano or fill the air with fragments of lava. Eruptions come in many different forms.
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CLICK BELOW TO GET PICTURES AND VIDEOS OF VOLCANOES
Educational Resources
Quiet eruptions occur in oceanic volcanoes which are formed from mafic magma. The lava from mafic magma tends to be runny and have low viscosity. Since the magma has a low viscosity, gases are able to escape very easily. As a result, the eruptions from these volcanoes tend to be quiet. The oceanic volcanoes located in Hawaii tend to have quiet eruptions.
Explosive eruptions occur most often in continental volcanoes. These volcanoes produce felsic lava that is sticky, cooler, and has high viscosities. There are large amounts of trapped gases like water vapor and carbon dioxide.
Once these volcanoes erupt, the lava's dissolved gases escape and send molten and solid particles into the air. Both quiet and explosive eruptions send different types of rock material onto the surface and into the air.
A volcano is a place on the Earth's surface (or any other planet's or moon's surface) where molten rock, gases and pyroclastic debris erupt through the earth's crust. Volcanoes vary quite a bit in their structure - some are cracks in the earth's crust where lava erupts, and some are domes, shields, or mountain-like structures with a crater at the summit.
Magma is molten rock within the Earth's crust. When magma erupts through the earth's surface it is called lava. Lava can be thick and slow-moving or thin and fast-moving. Rock also comes from volcanoes in other forms, including ash (finely powdered rock that looks like dark smoke coming from the volcano), cinders (bits of fragmented lava), and pumice (light-weight rock that is full of air bubbles and is formed in explosive volcanic eruptions - this type of rock can float on water).Volcanic eruptions can cause great damage and the loss of life and property.
The Word Volcano:
The word volcano comes from the Roman god of fire, Vulcan. Vulcan was said to have had a forge (a place to melt and shape iron) on Vulcano, an active volcano on the Lipari Islands in Italy.
Extreme Volcanoes:
The largest volcano on Earth is Hawaii's Mauna Loa. Mauna Loa is about 6 miles (10 km) tall from the sea floor to its summit (it rises about 4 km above sea level). It also has the greatest volume of any volcano, 10,200 cubic miles (42,500 cubic kilometers). The most active volcano in the continental USA is Mt. St. Helens (located in western Washington state).
The largest volcano in our Solar System is perhaps Olympus Mons on the planet Mars. This enormous volcano is 17 miles (27 km) tall and over 320 miles (520 km) across.
| Volcano Quiz Printout | Volcanoes |
ASSIGNMENT= Please click the website below and play the game.
Then 1) Explain in your journal exactly what happened. and
2) Explain in your journal why you think it happened in the way it did? http://perspective.pearsonaccess.com/content/resources/learningresources/sc/viewresource.html?swf=swf/actart_casc_mtsthelens
Assignment=Copy in your journal an Circle the right answer
Circle the right answer:1. What is the name of molten rock that erupts from volcanoes? MAGMA - LAVA - VENT
2. What is the name of molten rock within the Earth's crust? MAGMA - LAVA - VENT
3. What is the name of the tube through which molten rock flows? PARASITIC - CONDUIT - BASE
4. In which part of the Earth would you find a magma reservoir? CRUST - PARASITIC - CONDUIT
5. Composite volcanoes are made up of layers of lava and ______. CONDUIT - ASH - MAGMA
6. What is the name of a smaller vent-structure on the side of some volcanoes? SUMMIT - MAGMA RESERVOIR - PARASITIC CONE
7. What is the name of the bowl-like opening of a volcano? SILL - CRATER - ASH
8. Are ash clouds emitted from sills? YES - NO
9. What is the name of an opening through which molten rock and gases escape from a volcano? CONDUIT - VENT - FLANK
10. The sides of a volcano are called its flanks. YES - NO
•The sun is the main source of energy that cause changes in the water on Earth.
Assignment=Please watch these 2 videos and take 7-12 notes from each video in your journal
The Water Cycle
•Driven by the energy of the sun, water cycles, changing from one form to another through the amount of
the same.
Assignment= Please explain the relationship between the sun and the Water Cycle on Earth. Answer in a 3-6 sentence paragraph in your journal.
2) Summarize in your journal what PRECIPITATION is
3) Summarize in your journal what COLLECTION IS
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Water can be found in different states and in different forms (salt, fresh + brackish), but the amount of water on Earth remains the same!!
Research Assignment= Look upon the internet, and explain the makeup of fresh water, salt water and brackish water, and put this information in your journal
Assignment=Copy in your journal and fill in the right answer
Raindrop - Level 2
Where is Earth's water located?
Yep, the Earth is doing a balancing act with its water!
Water is continually moving around, through, and above the Earth as water vapor, liquid water, and ice. In fact, water is continually changing its form. The Earth is pretty much a "closed system," like a terrarium. That means that the Earth neither, as a whole, gains nor loses much matter, including water. Although some matter, such as meteors from outer space, are captured by Earth, very little of Earth's substances escape into outer space. This is certainly true about water. This means that the same water that existed on Earth millions of years ago is still here. Thanks to the water cycle (view agraphic of the water cycle), the same water is continually being recycled all around the globe. It is entirely possible that the water you drank for lunch was once used by Mama Allosaurus to give her baby a bath.By the way, there is a theory that much of Earth's water came from comets hitting the planet over billions of years.
Water on and in the Earth
Picture of Earth showing if all Earth's water (liquid, ice, freshwater, saline) was put into a sphere it would be about 860 miles (about 1,385 kilometers) in diameter. Diameter would be about the distance from Salt Lake City, Utah to Topeka, Kansas, USA.
Credit: Illustration by Jack Cook, Woods Hole Oceanographic Institution; USGS.
View full size
Credit: Illustration by Jack Cook, Woods Hole Oceanographic Institution; USGS.
View full sizeWhere is Earth's water located and in what forms does it exist? You can see how water is distributed by viewing these bar charts. The left-side bar shows where the water on Earth exists; about 97 percent of all water is in the oceans. The middle bar shows the distribution of that three percent of all Earth's water that is freshwater. The majority, about 69 percent, is locked up in glaciers and icecaps, mainly in Greenland and Antarctica. You might be surprised that of the remaining freshwater, almost all of it is below your feet, as ground water. No matter where on Earth you are standing, chances are that, at some depth, the ground below you is saturated with water. Of all the freshwater on Earth, only about 0.3 percent is contained in rivers and lakes—yet rivers and lakes are not only the water we are most familiar with, it is also where most of the water we use in our everyday lives exists.
In the pie charts above, the top pie chart shows that over 99 percent of all water (oceans, seas, ice, most saline water, and atmospheric water) is not available for our uses. And even of the remaining fraction of one percent (the small brown slice in the top pie chart), much of that is out of reach. Considering that most of the water we use in everyday life comes from rivers (the small dark blue slice in the bottom pie chart), you'll see we generally only make use of a tiny portion of the available water supplies. The bottom pie shows that the vast majority of the fresh water available for our uses is stored in the ground(the large grey slice in the second pie chart).
For a detailed explanation of where Earth's water is, look at the data table below. Notice how of the world's total water supply of about 332.5 million cubic miles (about 1,385 million cubic kilometers) of water, over 96 percent is saline. And, of the total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Thus, rivers and lakes that supply surface water for human uses only constitute about 22,300 cubic miles (93,100 cubic kilometers), which is about 0.007 percent of total water, yet rivers are the source of most of the water people use.
| Water source | Water volume, in cubic miles | Water volume, in cubic kilometers | Percent of freshwater | Percent of total water |
|---|---|---|---|---|
| Oceans, Seas, & Bays | 321,000,000 | 1,338,000,000 | -- | 96.5 |
| Ice caps, Glaciers, & Permanent Snow | 5,773,000 | 24,064,000 | 68.6 | 1.74 |
| Ground water | 5,614,000 | 23,400,000 | -- | 1.7 |
| Fresh | 2,526,000 | 10,530,000 | 30.1 | 0.76 |
| Saline | 3,088,000 | 12,870,000 | -- | 0.93 |
| Soil Moisture | 3,959 | 16,500 | 0.05 | 0.001 |
| Ground Ice & Permafrost | 71,970 | 300,000 | 0.86 | 0.022 |
| Lakes | 42,320 | 176,400 | -- | 0.013 |
| Fresh | 21,830 | 91,000 | 0.26 | 0.007 |
| Saline | 20,490 | 85,400 | -- | 0.007 |
| Atmosphere | 3,095 | 12,900 | 0.04 | 0.001 |
| Swamp Water | 2,752 | 11,470 | 0.03 | 0.0008 |
| Rivers | 509 | 2,120 | 0.006 | 0.0002 |
| Biological Water | 269 | 1,120 | 0.003 | 0.0001 |
| Source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York). | ||||
Investigate the water cycle (in over 60 languages!)How Does the proximity (closeness) to large bodies of water affect the weather
This process increases the likelihood of rainfall in the water increases humidity in surrounding area: Water from lake ( or other body of water) evaporates and turns into moisture in the air. The water vapor-rich air spreads out through diffusion and with wind.
This process increases the likelihood of rainfall in the water increases humidity in surrounding area: Water from lake ( or other body of water) evaporates and turns into moisture in the air. The water vapor-rich air spreads out through diffusion and with wind.
Assignment= Please copy into your journal and complete this graphic organizer about "Weather and Bodies of Water"
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Assignment=Please watch the video and TAKE 10-15 NOTES IN YOUR JOURNAL
Mountains can affect the climate of nearby lands. In some areas, mountains block rain, so that one side of a mountain range may be rainy and the other side may be a desert.
Assignment= Please copy into your journal and complete this graphic organizer about "Mountains and Weather"
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Greenhouse Effect.
You know that the sun is the source of all energy on earth. But sometimes we get a double dose of that energy. Solar radiation reaches the earth. The earth soaks up some of it and reflects some back to the atmosphere. The reflected radiation is absorbed by the gases in the atmosphere. The gases act like the glass walls of a greenhouse. They trap the warm air in and reflect it back to earth again. Scientists call this the greenhouse effect.
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 | The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere(water vapor, carbon dioxide, nitrous oxide, and methane, for example) trap energy from the sun. Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder. Because of how they warm our world, these gases are referred to as greenhouse gases. |  |
  Have you ever seen a greenhouse? Most greenhouses look like a small glass house. Greenhouses are used to grow plants, especially in the winter. Greenhouses work by trapping heat from the sun. The glass panels of the greenhouse let in light but keep heat from escaping. This causes the greenhouse to heat up, much like the inside of a car parked in sunlight, and keeps the plants warm enough to live in the winter.The Earth’s atmosphere is all around us. It is the air that we breathe. Greenhouse gases in the atmosphere behave much like the glass panes in a greenhouse. Sunlight enters the Earth's atmosphere, passing through the blanket of greenhouse gases. As it reaches the Earth's surface, land, water, and biosphere absorb the sunlight’s energy. Once absorbed, this energy is sent back into the atmosphere. Some of the energy passes back into space, but much of it remains trapped in the atmosphere by the greenhouse gases, causing our world to heat up. The Positive Parts of the Greenhouse Effect The greenhouse effect is important. Without the greenhouse effect, the Earth would not be warm enough for humans to live. But if the greenhouse effect becomes stronger, it could make the Earth warmer than usual. Even a little extra warming may cause problems for humans, plants, and animals. | ||
Assignment= Please copy into your journal and complete this graphic organizer about Ther Positive Parts of the Greenhouse Effect
Then 1) Explain in your journal exactly what happened. and
2) Explain in your journal why you think it happened in the way it did?
GREENHOUSE EFFECT GAME
Planet Disaster? The Negative Parts of the Greenhouse Effect
Scientists warn about the dangers of a changing climate.
October , 2008
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| Go Green! Mathez says that everyone can help in the fight against climate change. "What each individual person does may not have an observable impact," says Mathez. "But if everyone changed their lifestyle, it could make a difference." One suggestion: Use fluorescent lights instead of standard light bulbs. Fluorescent bulbs run on less energy and cut down on the amount of fossil fuels you use. You can also save energy by riding your bike to school instead of having your parents drive you by car. Mathez says that the most important change that needs to be made is for governments to work together to develop policies to reduce fossil-fuel use. "We need to start to rely more on a combination of renewable energy sources, like wind and solar power," he says. |
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The world's climate is changing. Scientists say the effects of these changes could be devastating to living things on Earth — including humans. It's likely that people your age will see these effects firsthand. But your generation may also help find solutions to the problems.
Scientists say that one of the biggest causes of climate change is the rising level of carbon dioxide gas in the air. Many power plants, factories, and cars run on fossil fuels like oil. Burning these fuels releases carbon dioxide gas into the air. This gas traps heat in the atmosphere, causing Earth's climate to warm. That process is known as global warming."We don't know exactly what is going to happen due to climate change," says Ed Mathez, a geologist and curator of the upcoming exhibition Climate Change, at the American Museum of Natural History in New York City. The processes that control Earth's climate are complicated, and scientists don't know how the amount of carbon dioxide in the atmosphere will change over time. Despite this uncertainty, researchers are trying to tackle the problem of climate change head-on. "It is better to prepare now for the potential negative consequences," says Mathez.
Assignment= Please copy into your journal and complete this graphic organizer about this
Wacky Weather
Global warming may result in potentially deadly changes to the world's weather. During the summer of 2003, approximately 35,000 people died when Europe experienced an extreme heat wave. "Events like this will become more frequent as global warming intensifies," says Mathez.
Scientists say that global warming could also cause more severe storms, such as the tornadoes that strike the Midwest each year. With global warming, more water evaporates from the oceans. This process transfers heat from the oceans into the atmosphere. That additional heat fuels more storms. "We already can see a greater number of storms," says Mathez.
Assignment= Please copy into your journal and complete this graphic organizer about Wacky Weather
Dry Land
While storms are expected to slam some areas of the world, scientists are also concerned that global warming will cause other areas to experience long and severe droughts. Mathez says that places like the Southwestern United States could even see decade-long dry spells, called "mega-droughts."
Scientists aren't sure about the exact relationship between climate change and drought. But they suspect that global warming changes weather patterns, affecting the amount of rainfall.
Over the past several years, drought in California has caused soil, grasses, and trees to dry out. That has resulted in more frequent wildfires. In 2007, more than 4,047 square kilometers (1,000,000 acres) of land in California were destroyed by raging wildfires.
Assignment= Please copy into your journal and complete this graphic organizer about "Dry Land"
Changing Oceans
Scientists are concerned that the rising levels of carbon dioxide gas in the atmosphere will also cause trouble for ocean life. When carbon dioxide gas mixes with ocean water, it changes the composition of the water. The changing water chemistry can be harmful to animals with hard shells, such as corals. The coral animals that create tropical reefs are dying in places like the Gulf of Mexico.
"If the reefs die out, the many hundreds of animals that rely on them for shelter and as a food source might disappear," says Mathez.
Assignment= Please copy into your journal and complete this graphic organizer about "Changing Oceans"
Rising Seas
As the atmosphere and oceans warm, giant sheets of ice that cover land in Antarctica and Greenland are melting. Chunks of ice are sliding off the land and falling into the oceans.
One result of the melting ice is a rise in the level of the oceans. Scientists don't know by how much sea level will rise. But scientists fear that in the next 100 years, low-lying areas will be more likely to flood, especially during storms. Cities located on coasts, like New York City, London, and Shanghai, China, are all at risk for flooding. "If people want to continue to live in these cities, we may have to build giant seawalls to hold back the seawater," says Mathez.
Assignment= Please copy into your journal and complete this graphic organizer about "Rising Seas"
—Andrew Klein
Assignment= Please copy into your journal and complete this graphic organizer about "Planet Disaster"
ASSIGNMENT- Please copy in your journal and complete this Venn Diagram that compares the positive and negative parts of the "greenhouse effect"
Positive parts and Negative parts
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| GREENHOUSE EFFECT |
INTERNET ACTIVITY – GREENHOUSE EFFECT
•-4 pages of work
•www.greenhouse.gov.au
•Look up the website shown above.
Click on ‘Global Warming. Cool it!’ •
•Complete: and put your work in your journal
Global warming is caused by an increase in greenhouse gases in the a__________________________ of the Earth. The main greenhouse gases are w___________ v_________, carbon d________ , methane and nitrous oxide, as well as some manufactured gases such as chlorofluorocarbons (CFCs) and some of their replacements.
•
•How many tonnes of greenhouse gases does 1 Australian household make each year? ___________
•What are 3 effects that scientists have predicted because of greenhouse gases? ________________
•How many tonnes of greenhouse gases can the average family save each year? ___________
•What are 5 ways in which we generate greenhouse gases?
•Click on ‘to the start of the “How You Can Help” section’
•What types of lights should you install in your home?
•Should you leave lights on when not in use?
•Should wall paint be a light or a dark colour?
•Click on ‘Refrigerators and Freezers’
•What are 2 important things to think about when choosing and using a ‘fridge?
•Click on ‘Home Heating and Cooling’
•What are 2 important things to do to reduce the amount of electricity used for heating in winter and for cooling in summer? _________________________________________________
•Click on ‘Building and Renovating’
•What are 5 things to consider when building a new house?
•Click on ‘Food and Garden Waste’
•How does the greenhouse gas called methane form?
•Should food and garden waste decay with fresh air or no fresh air?
•What are 2 things you should do to break down kitchen and garden waste? _______
•Click on ‘Transport’
•What else can you do instead of using a car?
•If you must travel by car, how many people should be in the car? ____________
•When buying a car, what is 1 important environmentally friendly thing to consider?
The Earth's Geosphere
• The geosphere is the part of Earth way below our feet. It is the crust and mantle . The crust is the outer layer of the Earth. We stand on the top of the crust. The mantle is the layer beneath the crust. The inside of the Earth is very hot. Scientists learn a lot about our planet's insides from earthquakes and volcanoes. When volcanoes erupt, they send lava or liquid rock to the surface. There is also heat and pressure inside the Earth. This heat and pressure cause our mountains to form. Our hydrosphere includes all of the water on our planet. The oceans, rivers, lakes, streams, and ponds are part of the hydrosphere. Even the glaciers or large blocks of ice on Earth have water. We depend on the Earth's water for food and power. We not only use fresh water for drinking, but we also use the animals in the sea for food. Water is used to help make power. Some of our electricity is made from the power of water.
Assignment=Explain what a geosphere is in a short 2-5 sentence paragraph in your journal.
Assignment= Please click and watch this 12 minute movie and take between 10-25 notes in your journal
What is the water cycle?
What is the water cycle? I can easily answer that—it is "me" all over! The water cycle describes the existence and movement of water on, in, and above the Earth. Earth's water is always in movement and is always changing states, from liquid to vapor to ice and back again. The water cycle has been working for billions of years and all life on Earth depends on it continuing to work; the Earth would be a pretty stale place to live without it.Where does all the Earth’s water come from? Primordial Earth was an incandescent globe made of magma, but all magmas contain water. Water set free by magma began to cool down the Earth’s atmosphere, until it could stay on the surface as a liquid. Volcanic activity kept and still keeps introducing water in the atmosphere, thus increasing the surface- and ground-water volume of the Earth.
A quick summary of the water cycle
Here is a quick summary of the water cycle. The links in this paragraph go to the detailed Web pages in our Web site for each topic. A shorter summary of each topic can be found further down in this page, though.The water cycle has no starting point. But, we'll begin in the oceans, since that is where most of Earth's water exists. The sun, which drives the water cycle, heats water in the oceans. Some of it evaporates as vapor into the air. Ice and snow can sublimatedirectly into water vapor. Rising air currents take the vapor up into the atmosphere, along with water from evapotranspiration, which is water transpired from plants and evaporated from the soil. The vapor rises into the air where cooler temperatures cause it to condense into clouds. Air currents move clouds around the globe, cloud particles collide, grow, and fall out of the sky as precipitation. Some precipitation falls as snow and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Snowpacks in warmer climates often thaw and melt when spring arrives, and the melted water flows overland as snowmelt. Most precipitation falls back into the oceans or onto land, where, due to gravity, the precipitation flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, with streamflow moving water towards the oceans. Runoff, and ground-water seepage, accumulate and are stored as freshwater in lakes. Not all runoff flows into rivers, though. Much of it soaks into the ground as infiltration. Some water infiltrates deep into the ground and replenishes aquifers (saturated subsurface rock), which store huge amounts of freshwater for long periods of time. Some infiltration stays close to the land surface and can seep back into surface-water bodies (and the ocean) as ground-water discharge, and some ground water finds openings in the land surface and emerges as freshwater springs. Over time, though, all of this water keeps moving, some to reenter the ocean, where the water cycle "ends" ... oops - I mean, where it "begins."
Components of the water cycle
The U.S. Geological Survey (USGS) has identified 16 components of the water cycle:- Water storage in oceans
- Evaporation
- Sublimation
- Evapotranspiration
- Water in the atmosphere
- Condensation
- Precipitation
- Water storage in ice and snow
- Snowmelt runoff to streams
- Surface runoff
- Streamflow
- Freshwater storage
- Infiltration
- Groundwater storage
- Groundwater discharge
- Springs
Global water distribution
Also, find out how much water exists on (and in) the Earth and where it is located.Water storage in oceans: Saline water existing in oceans and inland seas
The ocean as a storehouse of water
The water cycle sounds like it is describing how water moves above, on, and through the Earth ... and it does. But, in fact, much more water is "in storage" for long periods of time than is actually moving through the cycle. The storehouses for the vast majority of all water on Earth are the oceans. It is estimated that of the 332,600,000 cubic miles (mi3) (1,386,000,000 cubic kilometers (km3)) of the world's water supply, about 321,000,000 mi3 (1,338,000,000 km3) is stored in oceans. That is about 96.5 percent. It is also estimated that the oceans supply about 90 percent of the evaporated water that goes into the water cycle.During colder climatic periods more ice caps and glaciers form, and enough of the global water supply accumulates as ice to lessen the amounts in other parts of the water cycle. The reverse is true during warm periods. During the last ice age glaciers covered almost one-third of Earth's land mass, with the result being that the oceans were about 400 feet (122 meters) lower than today. During the last global "warm spell", about 125,000 years ago, the seas were about 18 feet (5.5. meters) higher than they are now. About three million years ago the oceans could have been up to 165 feet (50 meters) higher.
Oceans in movement
If you have ever been seasick (we hope not), then you know how the ocean is never still. You might think that the water in the oceans moves around because of waves, which are driven by winds. But, actually, there are currents and "rivers" in the oceans that move massive amounts of water around the world. These movements have a great deal of influence on the water cycle. The Kuroshio Current, off the shores of Japan, is the largest current. It can travel between 25 and 75 miles (40 and 121 kilometers) a day, 1-3 miles (1.4-4.8 kilometers) per hour, and extends some 3,300 feet (1,000 meters) deep. The Gulf Stream is a well known stream of warm water in the Atlantic Ocean, moving water from the Gulf of Mexico across the Atlantic Ocean towards Britain. At a speed of 60 miles (97 kilometers) per day, the Gulf stream moves 100 times as much water as all the rivers on Earth. Coming from warm climates, the Gulf Stream moves warmer water to the North Atlantic.
Get all the details about water storage in the oceans.Evaporation: The process by which water is changed from liquid to a gas or vapor
Evaporation and why it occurs
Evaporation is the process by which water changes from a liquid to a gas or vapor. Evaporation is the primary pathway that water moves from the liquid state back into the water cycle as atmospheric water vapor. Studies have shown that the oceans, seas, lakes, and rivers provide nearly 90 percent of the moisture in our atmosphere via evaporation, with the remaining 10 percent being contributed by plant transpiration.Heat (energy) is necessary for evaporation to occur. Energy is used to break the bonds that hold water molecules together, which is why water easily evaporates at the boiling point (212° F, 100° C) but evaporates much more slowly at the freezing point. Net evaporation occurs when the rate of evaporation exceeds the rate of condensation. A state of saturation exists when these two process rates are equal, at which point, the relative humidity of the air is 100 percent. Condensation, the opposite of evaporation, occurs when saturated air is cooled below the dew point (the temperature to which air must be cooled at a constant pressure for it to become fully saturated with water), such as on the outside of a glass of ice water. In fact, the process of evaporation removes heat from the environment, which is why water evaporating from your skin cools you.
Evaporation drives the water cycle
Evaporation from the oceans is the primary mechanism supporting the surface-to-atmosphere portion of the water cycle. After all, the large surface area of the oceans (over 70 percent of the Earth's surface is covered by the oceans) provides the opportunity for such large-scale evaporation to occur. On a global scale, the amount of water evaporating is about the same as the amount of water delivered to the Earth as precipitation. This does vary geographically, though. Evaporation is more prevalent over the oceans than precipitation, while over the land, precipitation routinely exceeds evaporation. Most of the water that evaporates from the oceans falls back into the oceans as precipitation. Only about 10 percent of the water evaporated from the oceans is transported over land and falls as precipitation. Once evaporated, a water molecule spends about 10 days in the air. The process of evaporation is so great that without precipitation runoff, and discharge from aquifers, oceans would become nearly empty. Get all the details about evaporation.Sublimation: The changing of snow or ice to water vapor without melting
For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor without first melting into water. Sublimation is a common way for snow to disappear in certain climates.It is not easy to actually see sublimation happen, at least not with ice. One way to see the results of sublimation is to hang a wet shirt outside on a below-freezing day. Eventually the ice in the shirt will disappear. Actually, the best way to visualize sublimation is to not use water at all, but to use carbon dioxide instead, as this picture shows. "Dry ice" is solid, frozen carbon dioxide, which sublimates, or turns to gas, at the temperature -78.5 °C (-109.3°F). The fog you see in the picture is a mixture of cold carbon dioxide gas and cold, humid air, created as the dry ice sublimates.
Sublimation occurs more readily when certain weather conditions are present, such as low relative humidity and dry winds. It also occurs more at higher altitudes, where the air pressure is less than at lower altitudes. Energy, such as strong sunlight, is also needed. If I was to pick one place on Earth where sublimation happens a lot, I might choose the south side of Mt. Everest. Low temperatures, strong winds, intense sunlight, very low air pressure - just what is needed for sublimation to occur.
Get all the details about sublimation.Evapotranspiration: The process by which water vapor is discharged to the atmosphere as a result of evaporation from the soil and transpiration by plants.
Although some definitions of evapotranspiration include evaporation from surface-water bodies, such as lakes and even the ocean, on this Web site, evapotranspiration is defined as the water lost to the atmosphere from the ground surface and the transpiration of groundwater by plants through their leaves.Transpiration: The release of water from plant leaves
Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Transpiration is essentially evaporation of water from plant leaves. It is estimated that about 10 percent of the moisture found in the atmosphere is released by plants through transpiration.Plant transpiration is pretty much an invisible process—since the water is evaporating from the leaf surfaces, you don't just go out and see the leaves "breathing". During a growing season, a leaf will transpire many times more water than its own weight. A large oak tree can transpire 40,000 gallons (151,000 liters) per year.
Atmospheric factors affecting transpiration
The amount of water that plants transpire varies greatly geographically and over time. There are a number of factors that determine transpiration rates:- Temperature:Transpiration rates go up as the temperature goes up, especially during the growing season, when the air is warmer due to stronger sunlight and warmer air masses.
- Relative humidity: As the relative humidity of the air surrounding the plant rises the transpiration rate falls. It is easier for water to evaporate into dryer air than into more saturated air.
- Wind and air movement: Increased movement of the air around a plant will result in a higher transpiration rate.
- Soil-moisture availability: When moisture is lacking, plants can begin to senesce (premature ageing, which can result in leaf loss) and transpire less water.
- Type of plant: Plants transpire water at different rates. Some plants which grow in arid regions, such as cacti and succulents, conserve precious water by transpiring less water than other plants.
Get all the details about evapotranspiration.Water storage in the atmosphere: Water stored in the atmosphere as vapor, such as clouds and humidity
The atmosphere is full of water
The water cycle is all about storing water and moving water on, in, and above the Earth. Although the atmosphere may not be a great storehouse of water, it is the superhighway used to move water around the globe. There is always water in the atmosphere. Clouds are, of course, the most visible manifestation of atmospheric water, but even clear air contains water—water in particles that are too small to be seen. One estimate of the volume of water in the atmosphere at any one time is about 3,100 cubic miles (mi3) or 12,900 cubic kilometers (km3). That may sound like a lot, but it is only about 0.001 percent of the total Earth's water volume. If all of the water in the atmosphere rained down at once, it would only cover the ground to a depth of 2.5 centimeters, about 1 inch. Get all the details about water stored in the atmosphere.Condensation: The process by which water is changed from vapor to liquid
Condensation is the process in which water vapor in the air is changed into liquid water. Condensation is crucial to the water cycle because it is responsible for the formation of clouds. These clouds may produce precipitation, which is the primary route for water to return to the Earth's surface within the water cycle. Condensation is the opposite of evaporation.
You don't have to look at something as far away as a cloud to notice condensation, though. Condensation is responsible for ground-level fog, for your glasses fogging up when you go from a cold room to the outdoors on a hot, humid day, for the water that drips off the outside of your glass of iced tea, and for the water on the inside of your home windows on a cold day.Condensation in the air
Even though clouds are absent in a crystal clear blue sky, water is still present in the form of water vapor and droplets which are too small to be seen. Depending on meteorological conditions, water molecules will combine with tiny particles of dust, salt, and smoke in the air to form cloud droplets, which grow and develop into clouds, a form of water we can see. Cloud droplets can vary greatly in size, from 10 microns (millionths of a meter) to 1 millimeter (mm), and even as large as 5 mm. This process occurs higher in the sky where the air is cooler and more condensation occurs relative to evaporation. As water droplets combine (also known as coalescence) with each other, and grow in size, clouds not only develop, but precipitation may also occur. Precipitation is essentially water cloud in its liquid or solid form falling form the base of a cloud. This seems to happen too often during picnics or large groups of people gather at swimming pools.You might ask ... why is it colder higher up?
As we said, clouds form in the atmosphere because air containing water vapor rises and cools. The key to this process is that air near the Earth's surface is warmed by solar radiation. But, do you know why the atmosphere cools above the Earth's surface? Generally, air pressure, is the reason. Air has mass (and, because of gravity on Earth, weight) and at sea level the weight of a column of air pressing down on your head is about 14 ½ pounds (6.6 kilograms) per square inch. The pressure (weight), called barometric pressure, that results is a consequence of the density of the air above. At higher altitudes, there is less air above, and, thus, less air pressure pressing down. The barometric pressure is lower, and lower barometric pressure is associated with fewer molecules per unit volume. Therefore, the air at higher altitudes is less dense. Since fewer air molecules exist in a certain volume of air, there are fewer molecules colliding with each other, and as a result, there will be less heat produced. This means cooler air. Do you find this confusing? Just think, clouds form all day long without having to understand any of this. Get all the details about condensation.Precipitation: The discharge of water, in liquid or solid state, out of the atmosphere, generally upon a land or water surface
Precipitation is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail. It is the primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth. Most precipitation falls as rain.
How do raindrops form?
The clouds floating overhead contain water vapor and cloud droplets, which are small drops of condensed water. These droplets are way too small to fall as precipitation, but they are large enough to form visible clouds. Water is continually evaporating and condensing in the sky. If you look closely at a cloud you can see some parts disappearing (evaporating) while other parts are growing (condensation). Most of the condensed water in clouds does not fall as precipitation because their fall speed is not large enough to overcome updrafts which support the clouds. For precipitation to happen, first tiny water droplets must condense on even tinier dust, salt, or smoke particles, which act as a nucleus. Water droplets may grow as a result of additional condensation of water vapor when the particles collide. If enough collisions occur to produce a droplet with a fall velocity which exceeds the cloud updraft speed, then it will fall out of the cloud as precipitation. This is not a trivial task since millions of cloud droplets are required to produce a single raindrop.Precipitation rates vary geographically and over time
Precipitation does not fall in the same amounts throughout the world, in a country, or even in a city. Here in Georgia, USA, it rains fairly evenly all during the year, around 40-50 inches (102-127 centimeters (cm)) per year. Summer thunderstorms may deliver an inch or more of rain on one suburb while leaving another area dry a few miles away. But, the rain amount that Georgia gets in one month is often more than Las Vegas, Nevada observes all year. The world's record for average-annual rainfall belongs to Mt. Waialeale, Hawaii, where it averages about 450 inches (1,140 cm) per year. A remarkable 642 inches (1,630 cm) was reported there during one twelve-month period (that's almost 2 inches (5 cm) every day!). Is this the world record for the most rain in a year? No, that was recorded at Cherrapunji, India, where it rained 905 inches (2,300 cm) in 1861. Contrast those excessive precipitation amounts to Arica, Chile, where no rain fell for 14 yearsOn average, the 48 continental United States receives enough precipitation in one year to cover the land to a depth of 30 inches (0.76 meters).
Get all the details about precipitation.Water storage in ice and snow: Freshwater stored in frozen form, generally in glaciers, icefields, and snowfields
ice caps around the world
Although the water cycle sounds like it is describing the movement of water, in fact, much more water is in storage at any one time than is actually moving through the cycle. By storage, we mean water that is locked up in its present state for a relatively long period of time, such as in ice caps and glaciers.The vast majority, almost 90 percent, of Earth's ice mass is in Antarctica, while the Greenland ice cap contains 10 percent of the total global ice-mass. The Greenland ice cap is an interesting part of the water cycle. The ice cap became so large over time (about 600,000 cubic miles (mi3) or 2.5 million cubic kilometers (km3)) because more snow fell than melted. Over the millenia, as the snow got deeper, it compressed and became ice. The ice cap averages about 5,000 feet (1,500 meters) in thickness, but can be as thick as 14,000 feet (4,300 meters). The ice is so heavy that the land below it has been pressed down into the shape of a bowl. In many places, glaciers on Greenland reach to the sea, and one estimate is that as much as 125 mi3 (517 km3) of ice "calves" into the ocean each year—one of Greenland's contributions to the global water cycle. Ocean-bound icebergs travel with the currents, melting along the way. Some icebergs have been seen, in much smaller form, as far south as the island of Bermuda.
Ice and glaciers come and go
The climate, on a global scale, is always changing, although usually not at a rate fast enough for people to notice. There have been many warm periods, such as when the dinosaurs lived (about 100 million years ago) and many cold periods, such as the last ice age of about 20,000 years ago. During the last ice age much of the northern hemisphere was covered in ice and glaciers, and they covered nearly all of Canada, much of northern Asia and Europe, and extended well into the United States.Some glacier and ice cap facts
- Glacial ice covers 10 - 11 percent of all land.
- According to the National Snow and Ice Data Center (NSIDC), if all glaciers melted today the seas would rise about 230 feet (70 meters).
- During the last ice age (when glaciers covered more land area than today) the sea level was about 400 feet (122 meters) lower than it is today. At that time, glaciers covered almost one-third of the land.
- During the last warm spell, 125,000 years ago, the seas were about 18 feet (5.5 meters) higher than they are today. About three million years ago the seas could have been up to 165 feet (50.3 meters) higher.
Get all the details about water storage in ice and snow.Snowmelt runoff to streams: The movement of water as surface runoff from snow and ice to surface water
If you live in Florida or on the French Riviera you might not wake up everyday wondering how melting snow contributes to the water cycle. But, in the world-wide scheme of the water cycle, runoff from snowmelt is a major component of the global movement of water. In the colder climates much of the springtime runoff and streamflow in rivers is attributable to melting snow and ice. The effect of snowmelt on potential flooding, mainly during the spring, is something that causes concern for many people around the world. Besides flooding, rapid snowmelt can trigger landslides and debris flows.Contribution of snowmelt to streamflow
A good way to visualize the contribution of snowmelt to streamflow in rivers is to look at the hydrograph below, which shows daily mean streamflow (average streamflow for each day) for four years for the North Fork American River at North Fork Dam in California (real-time data streamflow). The large peaks in the chart are mainly the result of melting snow, although storms can contribute runoff also. Compare the fact that minimum mean-daily streamflow during March of 2000 was 1,200 cubic feet per second (ft3), while during August streamflows ranged from 55-75 ft3.
Get all the details about snowmelt runoff to streams.Surface runoff: Precipitation runoff which travels over the soil surface to the nearest stream channel
Surface runoff is precipitation runoff over the landscape
Many people probably have an overly-simplified idea that precipitation falls on the land, flows overland (runoff), and runs into rivers, which then empty into the oceans. That is "overly simplified" because rivers also gain and lose water to the ground. Still, it is true that much of the water in rivers comes directly from runoff from the land surface, which is defined as surface runoff.When rain hits saturated or impervious ground it begins to flow downhill. It is easy to see if it flows down your driveway to the curb and into a storm sewer, but it is harder to notice it flowing overland in a natural setting. During a heavy rain you might notice small rivulets of water flowing downhill. Water will flow along channels as it moves into larger creeks, streams, and rivers. Runoff flowing over bare soil deposits sediment into rivers, which is not good for water quality.
As with all aspects of the water cycle, the interaction between precipitation and surface runoff varies according to time and geography. Similar storms occurring in the Amazon jungle and in the desert Southwest of the United States will produce different surface-runoff effects. Surface runoff is affected by both meteorological factors and the physical geology and topography of the land. Only about a third of the precipitation that falls over land runs off into streams and rivers and is returned to the oceans. The other two-thirds is evaporated, transpired, or soaks into ground water. Surface runoff can also be diverted by humans for their own uses.
Get all the details about surface runoff.Streamflow: The movement of water in a natural channel, such as a river
The U.S. Geological Survey (USGS) uses the term "streamflow" to refer to the amount of water flowing in a river. Although USGS usually uses the term "stream" when discussing flowing water bodies, in these pages we'll use "rivers" more often to describe flowing creeks, streams, and rivers, since that is probably what you are more familiar with.Importance of rivers
Rivers are invaluable to not only people, but to life everywhere. Not only are rivers a great place for people (and their dogs) to play, but people use river water for drinking-water supplies and irrigation water, to produce electricity, to flush away wastes (hopefully, but not always, treated wastes), to transport merchandise, and to obtain food. Rivers are indeed major aquatic landscapes for all manners of plants and animals. Rivers even help keep the aquifers underground full of water by discharging water downward through their streambeds. And, we've already mentioned that the oceans stay full of water because rivers and runoff continually refreshes them.Watersheds and rivers
When looking at the location of rivers and also the amount of streamflow in rivers, the key concept to know about is the river's "watershed". What is a watershed? Easy, if you are standing on ground right now, just look down. You're standing, and everyone is standing, in a watershed. A watershed is the area of land where all of the water that falls in it and drains off of it goes into the same place. Watersheds can be as small as a footprint in the mud or large enough to encompass all the land that drains water into the Mississippi River where it enters the Gulf of Mexico. Smaller watersheds are contained in bigger watersheds. It all depends of the outflow point—all of the land above that drains water that flows to the outflow point is the watershed for that outflow location. Watersheds are important because the streamflow and the water quality of a river are affected by things, human-induced or not, happening in the land area "above" the river-outflow pointStreamflow is always changing
Streamflow is always changing, from day to day and even minute to minute. Of course, the main influence on streamflow is precipitation runoff in the watershed. Rainfall causes rivers to rise, and a river can even rise if it only rains very far up in the watershed—remember that water that falls in a watershed will eventually drain by the outflow point. The size of a river is highly dependent on the size of its watershed. Large rivers have watersheds with lots of surface area; small rivers have smaller watersheds. Likewise, different size rivers react differently to storms and rainfall. Large rivers rise and fall slower and at a slower rate than small rivers. In a small watershed, a storm can cause 100 times as much water to flow by each minute as during baseflow periods, but the river will rise and fall possibly in a matter of minutes and hours. Large rivers may take days to rise and fall, and flooding can last for a number of days. After all, it can take days for all the water that fell hundreds of miles upstream to drain past an outflow point. Get all the details about streamflow.Freshwater storage: Freshwater existing on the Earth's surface
One part of the water cycle that is obviously essential to all life on Earth is the freshwater existing on the land surface. Just ask your neighbor, a tomato plant, a trout, or that pesky mosquito. Surface water includes the streams (of all sizes, from large rivers to small creeks), ponds, lakes, reservoirs (man-made lakes), and freshwater wetlands. The definition of freshwater is water containing less than 1,000 milligrams per liter of dissolved solids, most often salt.
The amount of water in our rivers and lakes is always changing due to inflows and outflows. Inflows to these water bodies will be from precipitation, overland runoff, ground-water seepage, or tributary inflows. Outflows from lakes and rivers include evaporation and discharge to ground water. Humans get into the act also, as people make great use of diverted surface water for their needs. So, the amount and location of surface water changes over time and space, whether naturally or with human help. Certainly during the last ice age when glaciers and snowpacks covered much more land surface than today, life on Earth had to adapt to different hydrologic conditions than those which took place both before and after. And the layout of the landscape certainly was different before and after the last ice age, which influenced the topographical layout of many surface-water bodies today. Glaciers are what made the Great Lakes not only "great," but also such a huge storehouse of freshwaterSurface water keeps life going
From space, the Nile Delta in Egypt appears green, showing that life can even bloom in the desert if there is a supply of surface water (or ground water) available. Water on the land surface really does sustain life, and this is as true today as it was millions of years ago. I'm sure dinosaurs held their meetings at the local watering hole 100 million years ago, just as antelopes in Africa do today. And, since ground water is supplied by the downward percolation of surface water, even aquifers are happy for water on the Earth's surface. You might think that fish living in the saline oceans aren't affected by freshwater, but, without freshwater to replenish the oceans they would eventually evaporate and become too saline for even the fish to survive.Usable freshwater is relatively scarce
Freshwater represents only about three percent of all water on Earth and freshwater lakes and swamps account for a mere 0.29 percent of the Earth's freshwater. Twenty percent of all freshwater is in one lake, Lake Baikal in Asia. Another twenty percent is stored in the Great Lakes (Huron, Michigan, and Superior). Rivers hold only about 0.006 percent of total freshwater reserves. You can see that life on Earth survives on what is essentially only a "drop in the bucket" of Earth's total water supply! Get all the details about freshwater storage.Infiltration: The downward movement of water from the land surface into soil or porous rock
Groundwater begins as precipitation
Anywhere in the world, a portion of the water that falls as rain and snow infiltrates into the subsurface soil and rock. How much infiltrates depends greatly on a number of factors. Infiltration of precipitation falling on the ice cap of Greenland might be very small, whereas, as this picture of a stream disappearing into a cave in southern Georgia, USA shows, a stream can act as a direct funnel right into ground water!Some water that infiltrates will remain in the shallow soil layer, where it will gradually move vertically and horizontally through the soil and subsurface material. Eventually it might enter a stream by seepage into the stream bank. Some of the water may infiltrate deeper, recharging ground-water aquifers. If the aquifers are shallow or porous enough to allow water to move freely through it, people can drill wells into the aquifer and use the water for their purposes. Water may travel long distances or remain in ground-water storage for long periods before returning to the surface or seeping into other water bodies, such as streams and the oceans.
Subsurface water
As precipitation infiltrates into the subsurface soil, it generally forms an unsaturated zone and a saturated zone. In the unsaturated zone, the voids—that is, the spaces between grains of gravel, sand, silt, clay, and cracks within rocks—contain both air and water. Although a considerable amount of water can be present in the unsaturated zone, this water cannot be pumped by wells because it is held too tightly by capillary forces. The upper part of the unsaturated zone is the soil-water zone. The soil zone is crisscrossed by roots, openings left by decayed roots, and animal and worm burrows, which allow the precipitation to infiltrate into the soil zone. Water in the soil is used by plants in life functions and transpiration, but it also can evaporate directly to the atmosphere. Below the unsaturated zone is a saturated zone where water completely fills the voids between rock and soil particles.In places where the water table is close to the land surface and where the water can move through the aquifer at a high rate, aquifers can be replenished artificially
Get all the details about infiltration.Groundwater storage: Water existing for long periods below the Earth's surface
Stored water as part of the water cycle
Large amounts of water are stored in the ground. The water is still moving, possibly very slowly, and it is a part of the water cycle. Most of the water in the ground comes from precipitation that infiltrates downward from the land surface. The upper layer of the soil is the unsaturated zone, where water is present in varying amounts that change over time, but does not saturate the soil. Below this layer is the saturated zone, where all of the pores, cracks, and spaces between rock particles are saturated with water. The term ground water is used to describe this area. Another term for ground water is "aquifer," although this term is usually used to describe water-bearing formations capable of yielding enough water to supply peoples' uses. Aquifers are a huge storehouse of Earth's water and people all over the world depend on ground water in their daily lives.To find water, look under the table ... the water table
A hole dug at the beach is a great way to illustrate the concept of how at a certain depth the ground, if it is permeable enough to hold water, is saturated with water. The top of the pool of water in this hole is the water table. The water level in the hole is the same as the level of the ocean. Of course, the water level at the beach changes by the minute due to the movement of the tides, and as the tide goes up and down, the water level in the hole moves, too.In a way, the hole is like a dug well used to access ground water, albeit saline in this case. But, if this was freshwater, people could grab a bucket an supply themselves with the water they need to live their daily lives. You know that at the beach if you took a bucket and tried to empty the hole, it would refill immediately because the sand is so permeable that water flows easily through it, meaning our "well" is very "high-yielding" (too bad the water is saline). To access freshwater, people have to drill wells deep enough to tap into an aquifer. The well might have to be dozens or thousands of feet deep. But the concept is the same as our well at the beach—access the water in the saturated zone where the voids in the rock are full of water.
Get all the details about groundwater storage.Groundwater discharge: The movement of water out of the ground
There's more water than just what you can see
You see water all around you every day as lakes, rivers, ice, rain and snow. There are also vast amounts of water that are unseen—water existing in the ground. And even though ground water is unseen, it is moving below your feet right now. As part of the water cycle, ground water is a major contributor to flow in many streams and rivers and has a strong influence on river and wetland habitats for plants and animals. People have been using ground water for thousands of years and continue to use it today, largely for drinking water and irrigation. Life on Earth depends on ground water just as it does on surface water.Groundwater flows underground
Some of the precipitation that falls onto the land infiltrates into the ground to become ground water. Once in the ground, some of this water travels close to the land surface and emerges very quickly as discharge into streambeds, but, because of gravity, much of it continues to sink deeper into the ground. If the water meets the water table (below which the soil is saturated), it can move both vertically and horizontally. Water moving downward can also meet more dense and water-resistant non-porous rock and soil, which causes it to flow in a more horizontal fashion, generally towards streams, the ocean, or deeper into the ground.The direction and speed of ground-water movement is determined by the various characteristics of aquifers and confining layers (which water has a difficult time penetrating) in the ground. Water moving below ground depends on the permeability (how easy or difficult it is for water to move) and on the porosity (the amount of open space in the material) of the subsurface rock. If the rock has characteristics that allow water to move relatively freely through it, then ground water can move significant distances in a number of days. But ground water can also sink into deep aquifers where it takes thousands of years to move back into the environment, or even go into deep ground-water storage, where it might stay for much longer periods.
Get all the details about ground-water discharge.Spring: Place where a concentrated discharge of ground water flows at the ground surface
What is a spring?
A spring is a water resource formed when the side of a hill, a valley bottom or other excavation intersects a flowing body of ground water at or below the local water table. A spring is the result of an aquifer being filled to the point that the water overflows onto the land surface. They range in size from intermittent seeps, which flow only after much rain, to huge pools with a flow of hundreds of millions of liters per day.Springs may be formed in any sort of rock, but are more prevalent in limestone and dolomite, which fracture easily and can be dissolved by rainfall that becomes weakly acidic. As the rock dissolves and fractures, spaces can form that allow water to flow. If the flow is horizontal, it can reach the land surface, resulting in a spring.
Spring water is not always clear
Water from springs usually is remarkably clear. Water from some springs, however, may be "tea-colored." Spring water can be colored red, indicating iron and metals enrichment from ground water coming in contact with naturally occurring minerals present as a result of ancient volcanic activity in the area. In Florida, many surface waters contain natural tannic acids from organic material in subsurface rocks, and the color from these streams can appear in springs. If surface water enters the aquifer near a spring, the water can move quickly through the aquifer and discharge at the spring vent. The discharge of highly colored water from springs can indicate that water is flowing quickly through large channels within the aquifer without being filtered through the limestone.
Thermal springs
Thermal springs are ordinary springs except that the water is warm and, in some places, hot, such as in the bubbling mud springs in Yellowstone National Park, Wyoming. Many thermal springs occur in regions of recent volcanic activity and are fed by water heated by contact with hot rocks far below the surface. Even where there has been no recent volcanic action, rocks become warmer with increasing depth. In such areas water may migrate slowly to considerable depth, warming as it descends through rocks deep in the Earth. If it then reaches a large crevice that offers a path of less resistance, it may rise more quickly than it descended. Water that does not have time to cool before it emerges forms a thermal spring. The famous Warm Springs of Georgia and Hot Springs of Arkansas are of this type. Warm springs can even coexist in Greenland alonside of icebergs. Get all the details about springs.Global water distribution
For a detailed explanation of where Earth's water exists, look at the chart and data table below. By now, you know that the water cycle describes the movement of Earth's water, so realize that the chart and table below represent the presence of Earth's water at a single point in time. If you check back in a thousand or million years, no doubt these numbers will be different!Notice how of the world's total water supply of about 332.6 million cubic miles of water, over 96 percent is saline. And, of the total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Fresh surface-water sources, such as rivers and lakes, only constitute about 22,300 cubic miles (93,100 cubic kilometers), which is about 0.0067 percent of total water. Yet, rivers and lakes are the sources of most of the water people use everyday.
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