Earth and Space Science MCT Review Objectives 4.a.-4.h.
Objective 4.a. • Compare and contrast the lithosphere and the asthenosphere. • Advanced – 4a. Explain how the composition of the lithosphere and asthenosphere affects plate movement.
Structure of the Earth • Inner Core • Solid iron and nickel core • Temperatures at 6000°C • Although temperatures are hot, it is solid due to great pressure from the above layers • Outer Core • Molten (liquid) iron and nickel
Mantle • Solid layer of hot rock • Flows like a liquid because of tremendous heat and pressure. • Plastic-likemeans that the consistency of the rock is flowing but it is not a liquid • The asthenosphere is the mechanically weak deforming region of the upper mantle that is ductile, plastic, and free-flowing.
Crust • Solid, rocky outer layer of Earth • Crust is thinner below the oceans than below continents. • Lithosphere is the outermost shell of the planet that floats on top of the asthenosphere • Divided into plates that include ocean floor and land.
Objective 4.b. • Describe the cause and effect relationship between the composition of and movement within the Earth’s lithosphere.
Continental Drift Theory • Earth’s continents were once joined in a single large landmass called Pangaea that broke apart • Continents have drifted to their current location
Theory of Plate Tectonics • Crust rides on top of the plates • Plates ride on top of mantle which is in motion due to convection currents.
Two Types of Lithospheric Plates • Continental Crust: made of rocks that are less dense and ride higher on the mantle than oceanic crust. • Oceanic Crust: rocks that are more dense and ride lower on the mantle than continental crust.
Plate Boundaries • Movement of Earth plates are responsible for most major geological events and landforms • Volcanoes, earthquakes, mountain formation
Convergent Plate Boundaries • Boundaries that form when 2 plates collide or come together
Oceanic & Continental • The more dense oceanic plate is forced below the less dense continental plate. • Oceanic plate melts as it pushes into the mantle forcing hot magma & gas up to the surface • Forms a deep-ocean trench & a long chain of continental volcanic mountains • The movement of one plate under another is called subduction.
Two Continental Plates • Both plates are less dense than the asthenosphere. • Crumple up to form mountain ranges. • Earthquakes are very common but not volcanoes. • Formed the Himalaya Mountains.
Two Oceanic Plates • One plate is forced down into the mantle forming a deep ocean trench that sinks & melts • The plate that sinks will melt, form volcanoes, and eventually an island arc. • Ex. Japan, Philippines, Marianas Islands
Divergent Plate Boundaries • Forms when 2 plates move away from each other • Most occur on the ocean floor & form undersea mountain ranges called mid-ocean ridges. • Ex. Mid-Atlantic Ridge • Two divergent continental plates will form a rift valley. Ex: East African Rift
Transform Plate Boundaries • Two plates grind or slide past each other without creating or destroying the lithosphere. • Ex. North American & Pacific plates slide past each other in a north-south direction creating earthquakes.
Seismic Waves • Earthquake waves are known as seismic waves & they spread out in all directions from the focus. • The epicenter is the spot on Earth’s surface directly above the focus.
Types of Seismic Waves • Primary (P)-waves: Travel by stretching & compressing land as they pass (like a slinky) • Fastest waves • Secondary (S)-waves: move land side to side • Only travel through solids • Surface waves: move up and down on earth’s surface (like waves on a pond) • cause the most damage
Speed of Seismic Waves • Seismic waves move faster through solids than liquids because solids are more dense. • For example, waves would move faster through the rocky crust than through the liquid outer core.
Volcanoes and Plate Boundaries • Volcanoes often form where two oceanic plates collide or where an oceanic plate collides with a continental plate.
Objective 4.c. • Examine weather forecasting and describe how meteorologists use atmospheric features and technology to predict the weather. • Advanced – Predict a change in weather based on differences in pressure, heat, air movement, and humidity.
Types of Fronts • 1. A coldfront forms when a cold air mass pushes under a warm air mass. Cumulus clouds form and thunderstormsmay occur. • 2. A warm front forms when a warm air mass moves up and over a cold air mass. Cirrus and stratus clouds form and light, steady precipitation occurs.
Air Pressure • High-pressure systemsdevelop when an air mass sinks toward the ground. • Causes clear, calm weather. • Low-pressure systemsdevelop when an air mass rises. • Causes clouds and precipitation
Jet Streams • Jet streams are high-speed winds 10-15 km above the Earth’s surface. They form when cold air from the poles meets warm air from near the equator.
Objective 4.h. • Justify why an imaginary hurricane might or might not hit a particular area, using important technological resources.
What is a Hurricane? • A hurricane is a low-pressure system that forms over tropical oceans.
Paths of Hurricanes • Trade winds cause hurricanes to move east to west near the equator. • As hurricanes move north, they begin to turn back to the eastbecause of westerlies.
Strength of Hurricanes • Hurricanes weaken as they move over cooler water or land. • Lower air pressure = faster wind speeds.
Objective 4.d. • Research the importance of the conservation of renewable and nonrenewable resources, and justify methods that might be useful in decreasing the human impact on global warming.
Two Types of Resources • Renewableresources are resources that are constantly being recycled or replaced by nature. For example, sunlight, water, and air. • Nonrenewable resources are resources that are used up more quickly than they are replaced. For example, minerals and metals.
Ways to Conserve Energy • 1. Turn off lights when not in use. • 2. Car pool or use public transportation. • 3. Walk or ride a bike. • 4. Use energy efficient appliances or bulbs. • What are some other ways to conserve energy?