The Dynamic Earth: UNIT 2 (ch. 3)
Jan 22, 2016
The Dynamic Earth:
The Dynamic Earth:UNIT 2 (ch. 3)UNIT 2 (ch. 3)
3.1 OBJECTIVES
• Describe the composition and structure of the Earth.
• Describe the Earth’s tectonic plates.
• Explain the main cause of earthquakes and their effects.
• Identify the relationship between volcanic eruptions and climate change.
• Describe how wind and water alter the Earth’s surface.
Earth--a system
• The Earth can be divided into 4 different parts:
• geosphere (rock); most is located in the Earth’s interior.
• atmosphere (air); gases--nearly all of which are found in the first 30km above the Earth’s surface.
• hydrosphere (water); oceans, atmosphere, land, and soil.
• biosphere (living things); ~9km above the Earth’s surface down to the bottom of the ocean.
Seismic waves: learning about the Earth’s interior
• seismic waves: waves that travel through Earth’s interior during an earthquake.
• http://www.ccmr.cornell.edu/education/ask/?quid=1374 • 3 layers (based on their
composition/chemistry...less dense --> more dense):
• crust--thin outer layer; light elements; <1% of the Earth’s mass
• mantle--64% of Earth’s mass; made of rocks of “medium” density
• core--made of the most dense elements; ~3400km in radius
Earth’s Structure--based on physical (not chemical)
properties• 5 layers:
• lithosphere (outer layer) -- includes the crust and the uppermost part of the mantle; divided into tectonic plates
• asthenosphere -- solid layer of the mantle; made of rock that flows very slowly & allows tectonic plates to move on top of it
• mesophere -- lower part of the mantle
• outer core -- made of liquid nickel & iron
• inner core -- a sphere of solid nickel & iron at the center of the Earth
• http://chemistry.about.com/od/chemistry101/f/What-Is-The-Difference-Between-A-Chemical-Property-And-A-Physical-Property.htm
Assignment: outliningchecked tomorrow
• pg. 67-70
• Earthquakes
• Volcanoes
• Erosion
• complete either in your notebook along with your notes OR on your iPad using whatever format you typically take notes in.
• Check the section objectives at the beginning of the powerpoint to make sure that you are thorough with your notes!
3.2: The Atmosphere
• Made up of gases: ~78% Nitrogen, ~21% Oxygen, ~1% “other”... carbon dioxide, water vapor, methane,...
• constantly changing (volcanoes, photosynthesis, pollution)
• insulates the Earth’s surface, important to support life
• pulled toward the surface by gravity: density increases the closer you get to the Earth’s surface
4 Layers
• Based on temperature
• Troposphere: weather; densest layer; temp decreases with increasing altitude
• Stratosphere: temp increases with increasing altitude...why? Ozone absorbs the sun’s UV energy and warms the air. **Ozone (O3) reduces the amount of UV radiation that reaches Earth...IMPORTANT!
• Mesosphere: coldest layer
• Thermosphere: farthest layer from the Earth’s surface; lower portion is called the ionosphere...produces the aurora borealis (Northern lights)
Energy in the Atmosphere
• Energy from the sun is transferred in the atmosphere by 3 mechanisms (fig. 15 pg. 74-75):
• radiation: across space (feeling the warmth of a fire)
• conduction: flow of heat from a warmer object to a colder object when the 2 are in direct physical contact with one another (this is how air near the Earth’s surface is heated).
• convection: transfer of heat by air currents (hot air _______ and cool air ______); **convection currents
Heating the Atmosphere• ~1/2 of the solar E that enters the
atmosphere actually reaches the surface.
• the other 1/2 is absorbed or reflected by clouds, gases, dust, or the Earth’s surface (land and water).
• greenhouse effect: the process in which gases trap heat near the Earth
• w/o this process, the Earth would be too cold for life to exist.
• gh gases: water vapor, CO2, methane, nitrous oxide.
• http://epa.gov/climatestudents/basics/today/greenhouse-effect.html
3.3: Hydrosphere• Water cycle: the continuous
movement of water into the air, onto land, and then back to water sources.
• evaporation / transpiration
• condensation
• precipitation
• others!!
Create a Conceptual Model
• Use the educreations app to create a visual that depicts the water cycle and the processes involved.
• Additionally, you will need to explain (by recording your voice) the cycle and how all of the processes are interconnected.
• Submitted to me by Thursday ([email protected])
World Ocean
• The interconnected oceans of the Earth: Pacific (largest and deepest point), Atlantic, Indian, Arctic (sea ice = frozen sea water; pack ice = a large mass of sea ice)
• ~70% of the Earth’s surface
• difference compared with freshwater? (more salt...higher salinity)
Our Temperature Regulator
• our oceans absorb over 1/2 the solar radiation that reaches the planet’s surface
• Water absorbs and releases heat slower than land --> atmospheric T changes much more slowly than if there were no oceans
• without the oceans, our atmosphere and surface temperatures would be too extreme to support life!
Freshwater & Groundwater• Fresh: < 3%; most is locked up in
icecaps and glaciers...the “rest”, lakes, rivers, wetlands, soil, rock layers below the surface, and in the atmosphere
• Ground: < 1%; our drinking water AND supply for many agricultural / industrial uses
• aquifer: a rock layer that stores and allows the flow of groundwater.
• recharge zone: the surface of land where water enters an aquifer.
Biosphere...the ‘skin’ of the apple :)
• ~12km down into the ocean and ~9km up into the atmosphere
• HOW?
• liquid water
• moderate temperatures
• energy source (T, photosynthesis, food chains/webs)
• requirements are continuously cycled
• gravity (atmosphere and cycling of materials)
closed vs. open systems
• open systems: both matter and E are exchanged btwn. the system and the surrounding environment
• closed systems: E enters and leaves the system, but matter does not.
• Earth?