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 (mmahar@gulllakecs.org)

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?