The Dynamic Earth:

1. The Dynamic Earth: • UNIT 2 (ch. 3)

2. 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.

3. 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.

4. 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

5. 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

7. 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!

8. 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

9. 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!

10. Mesosphere: coldest layer • Thermosphere: farthest layer from the Earth’s surface; lower portion is called the ionosphere...produces the aurora borealis (Northern lights)

11. 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

13. 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, nitrousoxide. • http://epa.gov/climatestudents/basics/today/greenhouse-effect.html

14. 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!!

15. 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 (mmahar@gulllakecs.org)

16. 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)

17. 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!

18. 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.

19. 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)

20. 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?