Dynamic+Earth

= Big Idea: Continuous processes on Earth's surface result in the formation and destruction of landforms and the formation of soil. =

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Essential Question: How do matter and energy move through Earth's spheres?
The Earth System and its Spheres //Students will learn that Earth is a system of interrelated spheres.//

https://www.classzone.com/books/earth_science/terc/content/investigations/es0103/es0103page02.cfm

Earth Is Divided Yet Connected
Earth is a very complex place. Although it looks like one large structure, it's actually got a lot going on that you may not see if you don't look closely. All of the processes on Earth are driven by four 'spheres,' which we describe individually, but are really all connected.

The names of each of these spheres come from Greek words that describe what they're made of: 'Geo' for 'ground,' 'hydro' for 'water,' 'bio' for 'life' and 'atmo' for 'air.' Let's look at each of the four spheres in a bit more detail to gain a better understanding of how they help make up the Earth.

The Geosphere
Since 'geo' means 'ground,' the geosphere describes all of the rocks, minerals and ground that are found on and in Earth. This includes all of the mountains on the surface, as well as all of the liquid rock in the mantle below us and the minerals and metals of the outer and inner cores. The continents, the ocean floor, all of the rocks on the surface, and all of the sand in the deserts are all considered part of the geosphere. Basically, if it looks like solid ground, it's part of the 'ground' sphere.

The Hydrosphere
Knowing that 'hydro' means 'water,' you may have guessed that the hydrosphere is made up of all the water on Earth. This includes all of the rivers, lakes, streams, oceans, groundwater, polar ice caps, glaciers and moisture in the air (like rain and snow). The hydrosphere is found on the surface of Earth, but also extends down several miles below, as well as several miles up into the atmosphere. Most of Earth's water is salty and in the oceans - about 97%. Two-thirds of the remaining 3% is frozen in glaciers and polar ice caps. Only 1% of the hydrosphere is liquid freshwater, and even most of this exists as groundwater down in the soil.

The Biosphere
The biosphere consists of all the living organisms on Earth. Their habitats extend from the upper areas of the atmosphere, to deep in the ground, to the bottom of the ocean – any place that life can exist.

The Atmosphere
The atmosphere is the layer of gases that surround the Earth. In comparison to the size of the Earth, it is a thin layer, composed primarily of nitrogen and oxygen with small amounts of carbon dioxide and other gases. The atmosphere is important for a number of reasons – it protects the Earth from incoming solar rays, it circulates the gases that plants and animals need to survive and it is responsible for our weather.

Interactions Between Spheres //Students will learn that interactions between spheres are essential for life on Earth.//

Although the four systems have their unique identities, there is substantial interaction between them. Environmental scientists study the effects of events in one sphere on the other spheres. For example, a volcanic eruption in the geosphere may cause profound direct and indirect effects on the hydrosphere, atmosphere and biosphere as follows:

//__**Example 1 (Volcano)**__// On May 18, 1980, Mount Saint Helens, in the state of Washington, erupted. This event altered the surrounding environment, and provided scientists with an opportunity to study the effects of volcanic eruptions on the geosphere, hydrosphere, atmosphere and biosphere. Such studies are vital because volcanic eruptions will continue to occur, and will have increasing impact on humans as people continue to settle lands closer to dormant volcanoes. The following are but a few of the myriad of interactions resulting from a volcanic eruption.

//__**Volcano**__//**>> geosphere >> atmosphere >> hydrosphere >> biosphere** Volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. These particles serve as nuclei for the formation of water droplets (hydrosphere). Rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere). Particulate matter in the air (atmosphere) falls out, initially smothering plants (biosphere), but ultimately enriching the soil (geosphere) and thereby stimulating plant growth (biosphere).

//__**Volcano**__//**>> geosphere >> hydrosphere >> biosphere** Volcanoes (events in the geosphere) may release a substantial amount of hot lava (geosphere), which causes mountain glaciers (hydrosphere) to melt. Mudflows (geosphere) and flooding may occur downstream from volcanoes and may inundate streamside communities (biosphere).

//__**Volcano**__//**>> geosphere >> atmosphere >> biosphere >> geosphere** Volcanoes (events of the geosphere) release a large amount of carbon dioxide (atmosphere), the raw material for sugar production in plants (biosphere). This may increase photosynthetic production and eventually increase the amount of biomass, which, after a very long time, forms coal and oil deposits (geosphere).

//**Volcano**//**>> complex interactions** <span style="background-color: #ffffff; color: #333333; font-family: Arial,Helvetica,sans-serif; font-size: 14.3px;">Volcanoes (geosphere) may emit large quantities of sulfur dioxide (atmosphere). When atmospheric sulfur dioxide combines with water (hydrosphere), sulfuric and sulfurous acid form. Rain (hydrosphere) may bring these acids to the Earth, acidifying soils (geosphere), lakes and rivers (hydrosphere). Acidic water leaches nutrients from the soil (geosphere) into the water table (hydrosphere), making the soil less fertile for plants (biosphere), and the subterranean water supply (hydrosphere) less potable for humans (biosphere). Acid rain falling on lakes and streams reduces the pH of the water (hydrosphere), which may result in a decrease in phytoplankton and zooplankton growth (biosphere). If photosynthesis is reduced, atmospheric concentrations of carbon dioxide can build up and stimulate global warming (atmosphere) which may contribute to increased melting of glaciers (hydrosphere).

The surface of the geosphere, where the rocky part of our planet is in contact with water, air, and/or life is generally where the spheres intersect and affect each other. The processes that move matter and energy from one sphere to another are called sphere interactions.
 * [[image:https://www.classzone.com/books/earth_science/terc/content/investigations/es0103/images/es0103_p3_gcdam_b.jpg width="170" height="210"]] || Several examples of sphere interactions can be inferred from this photograph: Humans (biosphere) built a dam out of rock materials (geosphere).
 * Water in the lake (hydrosphere) seeps into the cliff walls behind the dam, becoming groundwater (geosphere), or evaporating into the air (atmosphere).
 * Humans (biosphere) harness energy from the water (hydrosphere) by having it spin turbines (geosphere) to produce electricity. ||
 * Bud Rusho, Bureau of Reclamation, 1984 ||
 * Glen Canyon Dam holds back the waters of the Colorado River to form Lake Powell. ||  ||   ||   || [[image:https://www.classzone.com/books/earth_science/terc/images/spacer.gif width="10" height="1"]] || [[image:https://www.classzone.com/books/earth_science/terc/images/spacer.gif width="1" height="8"]] ||


 * [[image:https://www.classzone.com/books/earth_science/terc/content/investigations/es0103/images/es0103_p4_cornfields_b.jpg width="340" height="313"]] || What sphere interactions can you infer from this photograph? To identify sphere interactions, think of one feature in the image at a time, decide which sphere it is a part of, then consider how it interacts with the other spheres.

Plants (biosphere) draw water (hydrosphere) and nutrients from the soil (geosphere) and release water vapor into the atmosphere. Humans (biosphere) use farm machinery (manufactured from geosphere materials) to plow the fields, and the atmosphere brings precipitation (hydrosphere) to water the plants. Energy from the sun is stored by plants (biosphere). When humans or animals (biosphere) eat the plants, they acquire the energy originally captured by the plants. Humans expend some of this energy arranging bricks and wood (geosphere and biosphere) into buildings. ||  || Contour-planted field in southwest Iowa. ||
 * USDA NRCS

Earth's Energy Budget //Students will learn that energy moves between Earth's spheres, but is never related or destroyed.//

The Earth receives energy from the Sun, and it also reflects and radiates energy back into space. This balance of incoming and outgoing energy creates our climate that supports life as we know it on Earth. The Law of Conservation of Energy states that energy can neither be created nor destroyed, but it can be transformed from one state to another.

Energy from the Sun is delivered as light energy, and some of that energy is used to warm the Earth, and the differences in densities of air and water between warm and cold regions of the atmosphere and oceans induce currents. Heat also drives the evaporation of water from the oceans and drives the water cycle. Some light energy is converted into chemical energy through photosynthesis, and stored as biomass. The petroleum we use today is the result of photosynthesis long ago. A small amount of the Sun's energy that reaches the Earth's surface is converted to electrical energy through photovoltaic cells and used to power lights and machines.

All of the energy that warms the atmosphere, oceans and land must be radiated back into space in order to maintain our current climate. If the amount of energy radiating back into space is decreased by even a very small amount, it can lead to warming. It is believed that increasing levels of carbon disoxide in the atmosphere has a 'greenhouse effect' of reducing the amount of energy radiated into space.

Essential Question: How does weathering change Earth's surface?
Weathering //Students will learn that weathering is a process that breaks down rock materials. Physical weathering is the break down of rock through motion, force, and other physical processes, while chemical weathering is the process by which rocks break down as a result of chemical reactions.//

Weathering is the breaking down or dissolving of rocks and mineral s on Earths surface. Water, ice, acids, soil, plants, animals, and changes temperature in are all agents of weathering.

Once the rock has been broken down, a process called transports the bits of rock and minerals away. No rock on Earths surface is hard enough to resist weathering. Together, the processes of weathering and erosion carved the Grand Canyon, in the U.S. state of Arizona. This massive canyon is 446 kilometers (277 miles) long, as much as 29 kilometers (18 miles) wide, and 1.6 kilometers (1 mile) deep.

Weathering and erosion constantly change the Earth. Weathering wears away exposed surfaces over time. It smooths sharp, rough areas on rocks. Weathering also helps create soil as tiny bits of weathered rock mix with plant and animal remains.

Weathering can be a mechanical or a chemical process. Often, these two types of weathering work together.

Mechanical weathering, also called physical weathering, causes rocks to crumble. Water seeps into cracks and crevices in rock. If the temperature drops low enough, the water will freeze. When water freezes, it expands. The ice then works as a wedge. It slowly widens the cracks and splits the rock. When ice melts, water performs the act of erosion by carrying away the tiny rock fragments lost in the split.
 * Mechanical Weathering**

Mechanical weathering also occurs as the rock heats up and cools down. The changes in temperature cause the rock to expand and contract. As this happens over and over again, the rock weakens. Over time, it crumbles.

Another type of mechanical weathering occurs when clay or other materials near hard rock absorb water. The clay swells with the water, breaking apart the surrounding rock.

Salt also works to weather rock. Saltwater sometimes gets into the cracks and pores of rock. If the saltwater evaporates, salt crystals are left behind. As the crystals grow, they put pressure on the rock, slowly breaking it apart.

Plants and animals are agents of mechanical weathering. The seed of a tree may sprout in soil that has collected in a cracked rock. As the roots grow, they widen the cracks, eventually breaking the rock into pieces. Over time, trees can break apart even large rocks. Even small plants, such as mosses, can enlarge tiny cracks as they grow.

Animals that tunnel underground, such as moles and prairie dogs, also work to break apart rock and soil. Other animals dig and trample rock above ground, causing rock to slowly crumble.

Chemical weathering changes the materials that make up rocks and soil. Sometimes, carbon dioxide from the air or soil combines with water. This produces a weak acid, called carbonic acid, that can dissolve rock.
 * Chemical Weatherin g **

Carbonic acid is especially effective at dissolving limestone. When the carbonic acid seeps through limestone underground, it can open up huge cracks or hollow out vast networks of caves. Carlsbad Caverns National Park, in the U.S. state of New Mexico, includes more than 110 limestone caves. The largest is called the Big Room. At about 1,200 meters (4,000 feet) long and 190 meters (625 feet) wide, it is the size of six football fields.

Sometimes, chemical weathering dissolves large regions of limestone or other rock on the surface of the Earth to form a landscape called karst. In these dramatic areas, the surface rock is pockmarked with holes, sinkholes, and caves. One of the worlds most spectacular examples of karst is Shilin, or the Stone Forest, near Kunming, China. Hundreds of slender, sharp towers of limestone rise from the landscape.

Another type of chemical weathering works on rocks that contain iron. These rocks rust in a process called oxidation. As the rust expands, it weakens the rock and helps break it apart.

Weathering is a natural process, but human activities can speed it up. For example, certain kinds of air pollution increase the rate of weathering. Burning, coal , natural gas and oil releases chemicals such as nitrogen oxide and sulfur dioxide into the atmosphere. When these chemicals combine with sunlight and moisture, they change into acids. They then fall back to Earth as acid rain. Acid rain rapidly weathers limestone,marble, and other kinds of stone. The effects of acid rain can be seen on gravestones. Names and other inscriptions can be impossible to read.
 * Weathering and People**

Acid rain has also damaged many historic buildings and monuments. At 71 meters (233 feet) tall, the Leshan Giant Buddha at Mount Emei in China is the worlds largest statue of the Buddha. It was carved 1,300 years ago and sat unharmed for centuries. But in recent years, acid rain has turned its nose black and made some of its hair crumble and fall.

Essential Question: How does water change the Earth's surface?
Erosion and Deposition //Students will learn that erosion and deposition changes Earth's surface. There are several agents that cause erosion and deposition.//

Deposition is the process by which rocks, sand and sediment are deposited by the forces of erosion. Deposition is intimately tied to the processes of weathering and erosion. First, rocks are broken down into small pieces. This process is known as "weathering." Small pieces of dirt and sand are then picked up by forces of nature in a process known as "erosion." When those sediments are left in a new place, this is called "deposition."

Erosion is different from weathering since erosion has the ** moving ** element. The main driving force behind all agents of erosion is ** gravity **. Without gravity the other major natural agents of erosion such as: ** wind, running water, glaciers, waves, and rain ** would not occur.

Formation of Landforms by Streams //Students will learn that some landforms result from stream erosion.//

Groundwater, Waves, and Currents //Students will learn the erosion can change the land. Waves and currents can cause shoreline changes and land formations.//

Essential Question: How do wind, ice, and gravity change Earth's surface?
Erosion and Deposition by Wind //Students will learn erosion and deposition.//

Erosion and Deposition by Ice //Students will learn that ice expands and scrapes land, causing erosion.//

Erosion and Deposition by Gravity //Students will learn that gravity causes erosion and deposition by pulling down on loose materials.// = =

Essential Question: How does soil form?
Soil Formation //Students will learn how soil forms.//

Soil Horizons //Students will learn about soil horizons,//

Soil Characteristics //Students will learn about the characteristics of soil.//

What evidence is there that continental drift has occurred?

 * The continents can be fitted together rather like a jigsaw.
 * Rock records show matching layers, mountain ranges and ancient basement rocks in continents that were once together.
 * Glacial striations (scratches) and erratics (rocks moved away by glacial ice from original bedrock) correspond between continents.
 * Some distinctive fossils found on the southern continents indicate that they came from one ancient single continent.
 * Magnetic records left in the rocks seem to show that the Earth’s poles have changed, but the current thinking is that this is not the case – it is the rocks (plates) that have moved.

While the mechanisms are still being discussed, the current thinking is that the upper mantle of the Earth is in a state of convection, with hot material rising under diverging zones (plates moving apart) and cool material sinking in subduction zones (one plate diving and sinking underneath another plate).

At converging plate boundaries, the plates collide and either mountains are formed or one plate is forced down into the mantle (subducted) under another. At transform plate boundaries, one plate slips alongside the other in the opposite direction.

The displacement and rearrangement of land masses over geologic time has helped to create biological diversity on our planet. Without the profound effects created by geological reconfiguration life on earth might have been very different from the way that it is now.

Continental drift is the movement of land masses due to the effects of plate tectonics. Originally all of the world’s surface land was located in one region on the globe, Pangea. This supercontinent supposedly began to separate late in the Triassic Period (245 to 208 million years ago) into a southern landmass, Gondwanaland, and the northern landmass Laurasia. Gondwanaland was composed of the modern day continents of India, Africa, Australia, Antarctica and South America. These continents began to break up and head towards their present day locations only some 130 million years ago. Because these two land masses were the only two continents on the face of the earth for about 520 million years they are perhaps two of the most important geological structures of the last billion years. Our modern understanding of continental drift, and the structures that it has produced, has inexorably impacted our understanding of the fossil record and has given us detailed information about the evolutionary history of animal species.

The earth is populated by tens, perhaps hundreds of millions of animal species. We can attribute this fantastic diversity, in part, to an evolutionary trend called speciation. Speciation is a phenomenon that normally takes place when a group of animals of the same species find themselves isolated from one another. They can be isolated geographically by great distances, rising mountains or large bodies of water.

They can also be isolated by biological or behavioral barriers. One species is distinguished from another by their inability to create viable offspring together, and this is the precise effect that isolation can have on an animal species. Once a group of animals of the same species becomes split apart or isolated, they begin to be changed, molded and fashioned by the hand of natural selection to more properly fit in with their surroundings. After a period of time these two groups begin to be so different anatomically and genetically that soon it becomes impossible for them to procreate. This inability for two animals, that were once the same species, to create viable offspring is called speciation.

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