Earth Layers Notes PDF

## **SECOND QUARTER EARTH SCIENCE** ### **EARTH** Why is Earth the ONLY planet in the Solar System that can support life? ### **GOLDILOCKS ZONE** - The range of distance with the right temperatures for water to remain liquid - Too Hot - Just Right - Too cold - Planet size: 1-2x Earth - To...

## **SECOND QUARTER EARTH SCIENCE** ### **EARTH** Why is Earth the ONLY planet in the Solar System that can support life? ### **GOLDILOCKS ZONE** - The range of distance with the right temperatures for water to remain liquid - Too Hot - Just Right - Too cold - Planet size: 1-2x Earth - Toxic Gas Zone > Earth's fundamental conditions are "JUST RIGHT" to support life. ### **FACTORS THAT MAKE EARTH HABITABLE** #### **TEMPERATURE** - Influences how quickly atoms and molecules move - Allows liquid water to exist on Earth's surface, which is favorable to life #### **WATER** - Dissolves and transports chemicals within and to and from a cell. - The existence of water in three phases is essential to Earth's diverse ecosystem. #### **ENERGY FROM THE SUN** - Organisms use light or chemical energy to run their life processes, such as photosynthesis used by producers like plants. #### **ATMOSPHERE** - Traps heat, shields the surface from harmful radiation and provides chemicals needed for life, such as nitrogen and carbon dioxide. - It regulates the balance of water, oxygen, and carbon dioxide. #### **NUTRIENTS** - Used to build and maintain an organism's body. #### **MAGNETIC FIELD** - A planet requires a rapidly rotating magnetic field to protect it from flares from nearby stars and harmful radiation. #### **EARTH** - Earth is the only planet in the solar system that supports life. - The densest planet in the solar system - Is the densest planet in the solar system - Its atmosphere also protects life on Earth from the possible impact of meteoroids, comets, and asteroids - The Earth's crust is divided into several separate solid plates that float around independently on top of the hot mantle below. ### **EARTH'S LAYER** - Earth has several layers: crust, mantle, outer core, and inner core. #### **CRUST** - The outermost layer of the Earth, and is made up of a very thin layer of solid rock. - The thinnest layer of the Earth. - 5-35 km thick beneath land - 1-8 km thick beneath the oceans - The crust of the Earth is broken into many pieces called plates. - The movement of these plates causes earthquakes. #### **EARTH'S LAYER** #### **2 TYPES OF CRUST** ##### **THE CONTINENTAL CRUST (UNDER THE LAND)** - About 25 miles (32 kilometers) thick under the continents (made of mostly Granite). ##### **THE OCEANIC CRUST (UNDER THE OCEAN)** - It is made of basalt. - Basalt is much denser than granite. - Because of this, the less dense continents ride on the denser oceanic plates #### **THE LITHOSPHERIC PLATES** - The crust of the Earth is broken into many pieces called plates. - The plates "float" on the soft, semi-rigid asthenosphere. #### **LITHOSPHERE** - The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock. #### **ASTHENOSPHERE** - It is a semi-rigid part of the middle mantle that flows like hot asphalt under a heavy weight. - The asthenosphere is the part of the mantle that moves and causes the tectonic plates of the crust to move as well. #### **EARTH'S LAYER** #### **MANTLE** - The largest layer of the Earth. - 2900km thick. - It is much hotter and can flow. - It includes the lithosphere and asthenosphere. - It is relatively flexible-it flows like a very viscous liquid. - It is very hot-1600°F at the top and 4000°F towards the center of the Earth. #### **EARTH'S LAYER** #### **2 LAYERS OF MANTLE** ##### **UPPER MANTLE** - The upper part of the mantle is made up of peridotite, a rock denser than rocks common in the crust. ##### **LOWER MANTLE** - The middle mantle composed of very hot dense rock that flows like asphalt under a heavy weight. The movement of the middle mantle (asthenosphere) is the reason that the crustal plates of the Earth move. #### **CONVECTION CURRENTS** - The middle mantle "flows" because of convection currents. - These are caused by the very hot material at the deepest part of the mantle rising, then cooling and sinking again, repeating this cycle over and over. #### **EARTH'S LAYER** #### **EARTH'S CORE** - The core of the Earth is like a ball of very hot metals. - The core is divided into 2 layers: Outer and Inner. - The core is SO hot and has SO much pressure, that if you were to go there you would be squished into something even smaller that a marble. #### **EARTH'S LAYER** #### **INNER CORE** - The inner core of the Earth has temperatures and pressures so great that the metals are squeezed together and are not able to move about like a liquid, but are forced to vibrate in place like a solid. #### **EARTH'S LAYER** #### **OUTER CORE** - It is like a ball of very hot metals, so hot that the metals in it are all in the liquid state. - It is composed of melted metals of nickel and iron. - The outer core is 2,250km thick. #### **PLATE** - The Earth's crust consists of several mobile plates, masses of crust that move independently of adjacent plates. #### **PLATE TECTONICS** - Dealing with structural features of the Earth (e.g., mountains, ocean basins). #### **PLATE TECTONICS** - The process involves the interaction of moving crustal plates and results in major structural features of the Earth. - It is a scientific theory that explains how major landforms are created as a result of Earth's subterranean movements. - The Theory of Plate Tectonics builds on Wegener's Theory of Continental Drift. - In the Theory of Plate Tectonics, it is tectonic plates, rather than continents, that are moving #### **WHAT IS THE DIFFERENCE BETWEEN PLATE TECTONICS TO TECTONIC PLATES** - Tectonic plates are the different pieces of the Earth's crust that move around as they float on top of the mantle. - Plate tectonics is how those pieces move and interact with each other. #### **DISTRIBUTION OF CONTINENTS AND OCEANS** - Why does the distribution of continents and oceans on Earth's surface matter? #### **WHAT IS THE RELATIONSHIP BETWEEN CONTINENTS AND OCEANS?** - Continents are large and continuous masses of land which are separated by expanses of water. - Oceans are large water bodies on the Earth. - The continental crust is thicker. The oceanic crust is thinner. - The continents cover 29% of the earth's surface and the remainder of it by the oceans. - The positions of continents and ocean bodies have not been the same in the past #### **THE CONTINENTAL DRIFT THEORY** - **ALFRED WEGENER** - A German meteorologist and polar explorer who put forward the theory of "CONTINENTAL DRIFT" - The study of maps led him to suppose that the continents had been once joined. - This supercontinent was named - **PANGAEA** #### **OCEAN FLOOR** - The ocean floor may be segmented into three major divisions based on the depth as well as the form relief. - **CONTINENTAL MARGINS** - It is the zone of the ocean floor that separates the thin oceanic crust from the thick continental crust. - Together, the continental shelf, continental slope, and continental rise are called continental margin. #### **SEA - FLOOR SPREADING** - **HARRY HESS** first proposed the concept in the 1960s. - Sea-floor spreading occurs when: - Magma rises to the surface and pushing the existing sea floor away from the ridges. - The colder denser materials sink pulling the seafloor away from the ocean ridge. - This way, a new oceanic crust is created. - There are currently seven plates that make up most of the continents and the Pacific Ocean. #### **FORCE FOR DRIFTING (WEGENER)** - Wegener suggested these forces responsible for the drifting of continents. - **POLAR-FLEEING FORCE:** - Caused by the rotation of the earth. - **TIDAL FORCE** - Due to the attraction of the moon and the sun that develops tides. - **SUN** #### **OCEAN FLOOR** - **ABYSSAL PLAINS** - An extensive plains that lie between continental margins and mid-oceanic ridges - **MID-OCEANIC RIDGES** - Interconnected chain of mountain systems within the ocean. - Has a rift at the center and a zone for intense volcanic activity. #### **SEA - FLOOR SPREADING** - The plate then, when subducts, this crust is destroyed where it melts and comes out of volcanoes or recycled back to a new oceanic crust. #### **THERE ARE 3 TYPES OF PLATE BOUNDARIES** 1. **Divergent boundaries** 2. **Convergent boundaries** 3. **Transform boundaries** #### **THERE ARE 3 TYPES OF PLATE BOUNDARIES** 1. **Divergent boundaries:** - New crust is generated as plates pull away from each other. - The site where the plates move away from each other is called **SPREADING SITES**. - Continent - Rift valley - Ocean- Mid-oceanic ridge 2. **Convergent boundaries** - Where the crust is destroyed as one plate dives under another. - **SUBDUCTION ZONE** - Between an oceanic to continental plate - Between two oceanic plates - Between two continental plates 3. **Transform boundaries** - Occurs when two plates grind past each other without destroying or reproducing lithosphere. - Earthquakes sometimes occur near transform faults. #### **WATER DISTRIBUTION ON EARTH'S SURFACE** - Where is the Earth's water located? - How much water exists on, in, and above our planet? #### **WATER DISTRIBUTION ON EARTH'S SURFACE** - The Earth it a watery place. - Water is a finite source. - The Earth cleans and replenishes the water supply through the Hydrologic cycle. - Water covers 71% of the Earth's surface. - 97% is saltwater - 2% is fresh water from frozen ice caps and glaciers - 1% is fresh water in lakes and streams, groundwater, and water vapor in the atmosphere #### **TERMINOLOGY** - **HYDROLOGY:** Study of the movement, distribution, and quality of the water on the earth. - **HYDROLOGISTS:** Use science to ensure that we have access to easily available clean water. - They watch the water cycle carefully and study our impacts upon it. - They identify problems and work to find solutions. #### **2 TYPES OF WATER ON EARTH** - **SALTWATER** - **FRESHWATER** #### **THE WATER CYCLE** - Has no beginning or end. - It is powered by the Sun - Naturally recycles our water. - Water moves from bodies of water, land, and living things on Earth's surface to the atmosphere and back to Earth's surface. #### **STEPS OF THE WATER CYCLE** #### **SURFACE WATER** - **RIVERS:** Begin as small streams (often in mountains where snow melts and runs downhill) - **TRIBUTARIES:** Streams and small rivers that feed into a main river. - **PONDS:** Bodies of fresh, still water. Smaller and shallower than lakes. Sunlight usually reaches to the bottom of all parts of the pond. Plants usually grow on the bottom. Ponds form when water collects in low-lying areas of land. - **LAKES:** Are much deeper and bigger than ponds. Sunlight does not reach the bottom in a deep lake. Lakes can form naturally or can be man-made. #### **SURFACE WATER** - **WETLANDS:** A land area that is covered with water during part or all of the year. Helps control floods and provides habitats for many species. - Three types of freshwater wetlands: - **Marshes** - grassy areas covered by shallow water. - **Swamps** - look like flooded forests with trees and shrubs sprouting from the water; usually in warm, humid climates. - **Bogs** - contain mostly mosses because water is usually acidic; found in cooler northern areas; often formed in depressions left by melting ice sheets thousands of years ago. #### **SURFACE WATER** - **COASTAL WETLANDS:** Contain both fresh and saltwater. - **SALT MARSHES:** Found along both coasts of the US; have tall strong grasses. - **MANGROVES FOREST:** Found along the southeastern coasts of the US; mangrove trees are short and thick tangled roots. #### **USING FRESH WATER RESOURCES** - How do people use water? - What are some ways to conserve available fresh water? - How do scientists classify sources of water pollution? #### **HOUSEHOLD PURPOSES:** - Toilets, laundry, cooking, showers, washing cars, watering the lawn, washing dishes - **INDUSTRY:** To cool machinery, produce materials such as paper toilets and sinks. #### **USING FRESH WATER RESOURCES** - How do people use water? - **TRANSPORTATION:** Ship items and people - **RECREATION:** Fishing, boating, swimming, and ice skating. - **AGRICULTURE:** Plants, more water is used for irrigation in the US than any other single purpose. #### **WATER ISSUES** - No one owns the water. - We all have to share it while we are here and remember to leave it usable for the future. - Water shortages happen when there is too little precipitation, people use it up too fast, or a combination of both. #### **CONSERVATION OF WATER** - Reduce water use - Recycle water - Reuse water #### **POLLUTION OF WATER** - The addition of any substance that has a negative effect on water or the living things that depend on the water. - Substances that cause water pollution are called **POLLUTANTS**. #### **SOURCES OF POLLUTION** - They are classified by how they enter the water - **POINT SOURCE** - A specific source of pollution - **NONPOINT SOURCE** - A widespread source that cannot be tied to a specific point of origin (runoff from the fields, streets, or construction sites.