Unit 3: Plate Tectonics & Earthquakes By: Tiffany Gilboy & Stephen Holly
“The tectonic plates “floats” on the asthensphere because they are less dense.” • Like Ice in Water
Convection currents move the plates. Warm magma rises because it is less dense, cool magma sinks because it is denser. • Like the water cycle.
Volcanoes and earthquakes are found mainly along plate boundaries. • Like trees form in cracks in rocks.
Mid- ocean ridge – divergent plate boundary – new basaltic crust – sea floor spreading. • Like when you take to gram crackers on frosting and push down and pull apart.
Divergent boundaries make oceans; convergent boundaries make mountains and volcanoes. • Like when you are on the moon your spine decompresses.
Trench – convergent boundary – subduction – crust is destroyed. • convergent boundaries- like on earth your spine compresses • trench- like when you dig a hole in the ground • Subduction- like a sinking boat
Ocean crust gets older, cooler, and denser as you move away from a mid- ocean ridge. • Like a island the farther from the volcano the older and cooler the rock.
Continental crust is much older than ocean crust. • like dinosaurs are older than humans
Magnetic polarity reversals proved sea floor spreading. • Like reverse reverses a cars tires.
Mountains are formed by uplift. • Lights are turned on by flipping a switch.
Hot spots are located away from plate boundaries – they are stationary- form chains of volcanic islands as a plate moves over them. • Houses aren’t located by fast moving rivers.
Earthquakes are the release of energy from the stress built up along faults or when plates collide. • Explosions are a rapid release of explosive gas.
Epicenter- the point on the earth’s surface where the earthquake appears to begin. • The Atlantic in hurricane season.
P-waves – aka primary or compressional waves – travel through solids, liquids and gases- fast. • A concrete saw.
S-waves – aka secondary or shear waves – travel only through solids (stops at the liquid outer core.) • A power drill.
P&S – waves are called body waves because the travel through the body of the earth. • An auger travels through the earth.
You need distances from 3 seismic stations to find the epicenter of an earthquake. • A GPS needs 3 towers to pinpoint location.
Shadow Zone – NO P or S waves – due to refraction of P-waves and S- Waves stop at outer core. • The dark corner of a light room.
Our Resources • www.google.com • Our ESRT books • Our head knowledge • Mrs. Van-Wert & Mr. Saks • Our lab and workbooks • And www.yahoo.com mail
Unit IV: Weathering, Erosion, & Surface Processes By: Danny Anderson Sadie Smith
The Basics • Weathering, by definition, is the breaking of rocks into smaller pieces. • Erosion is the movement of pieces of broken rock. Gravity causes this. • There are two types of weathering: physical weathering and chemical weathering.
Physical Weathering • Physical weathering breaks down rocks into smaller pieces, but of the same composition. • Physical weathering can help chemical weathering along by increasing surface area.
Chemical Weathering • Chemical weathering changes the composition of the material it breaks down. • Chemical weathering works better in warm, wet climates. • The more surface area, the faster chemical weathering will break down the material. • Harder minerals are more resistant to weathering than soft minerals. • Minerals such as calcite, limestone, and marble are least resistant to chemical weathering.
Streams • Water moves the most sediment on earth via suspension, which means carrying sediment in the water’s current. • Stream velocity is the fastest outside a bend in the stream (causes erosion) and slowest on the inside (causes depostion). This is called meander. • Stream velocity depends on discharge and slope.
Organization of SedimentsIn a River • Streams carry different sediments in their current. • The bigger sediments settle first when stream velocity decreases.. • Streams round sediments – the longer it has been in the stream, the rounder it will be. • Two types of sorting – vertical sorting and horizontal sorting. • Vertical sorting – big sediments on top, little on the bottom. • Horizontal sorting – big sediments near the mouth, smaller, further out in the body of water, because the velocity is decreasing.
Streams vs. Glaciers • Streams organize their sediments by size – unlike glacier deposits, which are unorganized. • Rivers and streams cut V-shaped valleys. • Glaciers cut out U-shaped valleys. V-shaped River Valley U-shaped Glacier Valley
Surface Process • Mature soils have three different horizons : A, B, and C. • Porosity is the volume of open space in rock or soil – doesn’t depend on sediment size. • Permeability is the ability to travel through spaces in rock or soil – larger the sediment, the more permeable it is.
Plateaus vs. Mountains Plateaus have flat rock layers, while mountains have more zigzagged rock layers. Mountain: zigzagged rock layers. Plateau: flat rock layers.
Acknowledgements We would like to thank Mr. Saks and Mrs. Van Wert, for educating us on the wonders of earth science. We would like to thank our fellow students, for making the education process easier, or, occasionaly, harder. Finally, we would like to thank our notes and reference tables. We owe them our undying gratitude. Thanks everyone!
97 Radiation-Transfer of energy through space-doesn’t require particles.
98 UV Radiation Infrared Radiation- UV Radiation from the sun is converted to Infrared Radiation on Earth.
99 UV Radiation-The hottest part of the day is after 1 pm. It takes time for Earth to absorb UV rays from the sun and convert it to IR radiation to heat the atmosphere.
100 Conduction-Transferof energyfrom particle to particle-mainly in solids.
101 Convection-Transfer of energy in a liquid or gas due to differences in density-warm, less dense material rises and cools; more dense material sinks.
Specific Heat- The higher a material’s specific heat, the more energy it takes to change its temperature. 102
103 Specific Heat-Goodabsorbers of energy are good radiators of energy.
105 Insolation:IncomingSolar Radiation- Direct rays (90 degrees) transfer more energy than indirect rays.
104 Absorbers-Rough, dark colored materials absorb more energy than smooth, light colored materials.
106 Direct Rays- We receive more direct rays in summer than in winter.
107 Heating and Cooling- Adiabatic cooling and heating is simply caused by air expanding (cools) or contracting (heats).
109 Air-Air expands as it rises because pressure decreases with altitude.
Water Cycle- Evaporation is a cooling process. Condensation is a heating process- helps warm the atmosphere. 110
Relative Humidity- Relative humidity is a measure of how much water is actually in the air relative to how much it could hold (capacity). 111
112 Air Temperature-As air temperature increases, capacity increases- Warm air holds more moisture than cool air because it is drier. Ai r Temperature Capacity
113 Relative Humidity- Relative humidity is usually highest in the morning/ evening when the air is cool. Average Temperatures Throughout The Day
114 Air-Air is saturated with moisture when it’s relative humidity is 100%.
Dewpoint- The dewpoint temperature is the temperature at which condensation begins. 115