TODAY S FOCUS LAYERS OF THE EARTH 8.6C investigate and describe applications of Newton s law of inertia, law of force and acceleration, and law of action-reaction such as in vehicle restraints, sports activities, amusement park rides, Earth s tectonic activities, and rocket launches
OUR HOME PLANET EARTH: What do you know about our planet?
WHAT WE KNOW - Earth is the third rock from the sun 70% water, 30% land Has the perfect conditions for life Is a dynamic and changing planet it is NEVER constant Actually has several sources of heat KEY IDEA: Changes in the Earth s crust demonstrate the laws of motion forces that exist in the universe also exist on and in our home planet
DYNAMIC EARTH (MEANS ACTIVE ) The Earth is NOT static or still, it is constantly moving and changing! Earthquakes, Tsunamis, Volcanoes all of these are ever changing, sometimes violent events on earth.
SO.HOW DO WE KNOW WHAT S INSIDE THE EARTH? Geologists record seismic waves and study how they travel through the medium of Earth. Seismic waves can travel along the surface of the Earth or through its interior. The waves speed up, slow down, or completely stop depending upon the properties of the medium they are passing through. Using these, we can find out composition and state of matter of each layer.
We know that the earth's core is predominantly iron, with some contaminants. How? DETERMINING COMPOSITION OF EARTH The speed of sound through the core (as measured from the velocity at which seismic waves travel across it) and the density of the core are quite similar to those seen in of iron at high pressures and temperatures. Iron is the only element that closely matches the seismic properties of the earth's core and is also sufficiently abundant
THE EARTH IS HOT, HOT HOT! The interior of the earth is hot. There are three main sources of heat in the deep earth: (1)heat from when the planet formed, which has not yet been lost (2)frictional heating, caused by denser core material sinking to the center of the planet (3)heat from the decay of radioactive elements.
THIS HEAT CAUSES MOVEMENT: Convection currents are an unbalanced force in the mantle that cause heat flow and movement of material within the earth connection what do unbalanced forces cause? This results in plate movement that causes earthquakes and volcanic eruptions to create mountains and ocean basins. Let s take a closer look at our Earth
A JOURNEY TO THE CENTER OF THE EARTH The further in you go temperature and pressure both increase There are four main layers that make up the Earth s interior: Crust Mantle Outer Core Inner Core
CROSS SECTION OF EARTH Label your diagram!
THE CRUST The layer of rock that forms Earth s outer skin It is about 10 miles deep and made of solid rock Continental crust is thicker than oceanic crust However, even though it is thinner, the oceanic crust is much denser than continental crust
OCEANIC CRUST VS. CONTINENTAL Oceanic crust Below the ocean Consists of basalt Very dense Continental crust Forms and contains large landmasses Consists of granite Less dense
THE MANTLE The mantle extends to a depth of approximately 1,800 miles It is made of solid and liquid-like rocky substance composed of mostly silicates compounds made of silicon and oxygen The uppermost part of the mantle and the crust together form a rigid layer called the lithosphere The asthenosphere is super-heated rock (molten) The remainder of the mantle is solid Upper mantel Lower mantel
LIQUID-LIKE PARTS OF THE MANTLE (ASTHENOSPHERE) Magma and lava are not actual liquid, but are a type of solid classified by it s ability to move like a liquid plasticity Plasticity ability of a solid to flow like a liquid when intense pressure and heat build up It is MOLTEN, but not a liquid! The asthenosphere is the layer of the Earth that lies below the lithosphere. It is a layer of solid rock that has so much pressure and heat the rocks can flow like a liquid. The rocks are less dense than the rocks in the lithosphere. This allows the tectonic plates in the lithosphere to move around on the Earth's surface by "floating" on the rocks that are slowly flowing like a liquid.
Lithosphere (hard) Asthenosphere (soft)
THE CORE Consists of two parts Outer core molten iron and nickel metal Inner core solid dense ball of iron and nickel metal
HEAT TRANSFER (THE MOVEMENT OF HEAT) Heat is transferred through: Radiation Conduction Convection Let s go through what each type of heat is first, before we apply it to the Earth.
RADIATION Radiation transfer of energy by electromagnetic waves (ex. Sun heating the Earth) Does not need matter to transmit heat
CONDUCTION Conduction transfers heat via direct molecular collision. Occurs when there is physical contact. Needs matter to transfer heat When you touch a pan that is on the stove, the fire's heat causes molecules in the pan to vibrate faster, making it hotter. The heat is transferred to your hand when you touch the handle.
CONVECTION Convection - The transfer of heat energy by movements of a fluid. (air, liquids and molten material are all considered fluid ) Heat moves (transfers) because the density of the fluid changes. Hot things are lighter. The fluid moves away from the heat source. Then by being away from the heat source, it begins to cool Again, it s density changes, it becomes heavier Heavy things sink, so it sinks back down, and it goes near the heat source again and the cycle repeats. Convection currents continue as long as heat exists!
CONVECTION IN THE MANTLE Heat from the Earth s core and from the mantle itself cause the convection currents in the mantle Convection currents are an unbalanced force that causes heat flow and the movement of material within the earth. This moving material results in earthquakes and volcanic eruptions to create mountains and ocean basins.
RE-CREATE THE DIAGRAM:
EARTH S INTERIOR G.O.