Plate Tectonics A Look Into Our Dynamic Earth
What are the Layers of the Earth? Crust Mantle Core (Outer and Inner)
What is the Crust? Forms Earth’s outer skin It is made up of rocks. It is the thinnest Layer This is the crust!
What is the Mantle? The layer below the crust. It is a solid layer of hot rock. It is the thickest Layer Here is the Mantle
What are the Layers of the Mantle? Lithosphere: The upper most layer of the mantle. (100km) It is a very rigid layer. It is part crust, part mantle.
What are the Layers of the Mantle? Asthenosphere: This is the hottest part of the mantle. It has the property of plasticity.
What is Plasticity? A solid that can move like a liquid.
What is the Core? Center of the Earth. The composition is Iron and Nickel.
Outer Core: liquid because of heat Inner Core: Solid because there is too much pressure to be a liquid What is the difference between the outer and inner core?
What is a wave? A wave is an oscillation (an up and down or back and forth motion) that travels from one place to another with a certain velocity.(speed and direction)
What are Mechanical Waves? These are waves that travel though matter. They require a medium. Examples: sound waves, water waves, seismic waves (Earthquake)
How do mechanical waves work? The wave travels by jumping from one particle of a medium to another. They transport energy and not material.
What is a medium? A medium is matter that a wave travels through. It can include solid, liquids, or gases.
How are mechanical waves started? Mechanical waves require an initial energy input. Once this initial energy is added, the wave will travel through the medium until all the energy has been transferred.
What are Electromagnetic Waves? These are waves that can travel through empty space. Examples: visible light, microwaves, x-rays, and radio waves
What are the characteristics of waves? Amplitude Wavelength Frequency Wave Speed
What is Amplitude? The distance a wave oscillates from its resting position (Larger amplitude = more energy)
What is Wavelength? The distance from any point on one wave to a corresponding point of an adjacent wave
What is Frequency? The number of oscillations produced in a certain amount of time – Frequency is measured in hertz (Hz)
What is Wave Speed? The distance a wave travels in a given amount of time –Waves move faster through some mediums than through others
What is a crest and trough? Crest= highest point Trough = lowest point
What is a Longitudinal Wave? A wave whose oscillation is parallel to the direction in which the wave travels
What is a Transverse Wave? When the oscillation of a wave is perpendicular to the direction in which the wave travels
What are Observation and Inferences? Observation: Gathering information using your 5 senses. (Touch, Taste, Smell, See, and Hear) Inference: An interpretation based on prior knowledge and observations
How Did Scientists Figure out what is inside the Earth? Indirect evidence- relying on evidence not actually seen. Geologists used an indirect method to study the Earth’s interior.
Earthquake Waves The speed of these seismic waves tell how the planet is put together. P- waves or compression waves can travel through solids, liquids and gases S-wave or shear can only travel through solids.
Heat Transfer Radiation: transfer of energy through empty space. Conduction: Heat transfer by direct contact of particles of matter.
Convection: Heat transfer by the movement of a fluid. Convection Current: Flow that transfers heat within a fluid.
Why we care… There are convection currents in the mantle (asthenosphere). They are created from the heat of the Earth and are the driving force of plate tectonics.
Continental Drift -Proposed by Alfred Wegener in Continental Drift states that all of the continents had once been joined in a single land mass and have since drifted apart.
Pangaea: Name of the Super continent
Evidence of continental drift Landforms: Mountain Ranges, coal deposits, fit like a puzzle Fossils: glossopteris (fern like plant) Climate: Glaciers, plants living where they shouldn’t. People rejected and forgot about Wegener’s theory for about 40 years
Sea Floor Spreading Discovered in the mid 1900’s using sonar (bouncing sound waves off underwater objects and then records the echo of the wave) Watch me
Evidence of sea floor spreading: 1. Molten material 2. Magnetic Stripes 3. Drilling samples (age of rocks)
Mid ocean ridge: The longest mountain chain in the world Molten material rises from the mantle and erupts. The molten material then spreads out, pushing older rock to the side
The Theory of Plate Tectonics Plate tectonics explains the formation, movement, and subduction of Earth’s plates Scientists believe that 225 million years ago all the continents were together (Pangaea) and are moving apart, but will come back together again.
A plate is a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust.plate Explains that pieces of the Earth’s lithosphere are in constant, slow movement, driven by convection currents in the mantle
Plate Boundaries These are places where 2 plates meet each other Causes Earthquakes and Volcanoes
Transform -Plates slide past each other -Lots of Earthquakes
Divergent - Plates move away from each other -Sea- floor spreading and rift valleys
Convergent Plates crash into each other
Everything Together
Credits Created by Michelle Riccobene All video from KLVX video streaming All pictures are from Google Images ( ) or Prentice Hall Earth Sciencewww.google.com