Third Quarter Wrap-up

Students
3/4's of the year has quickly gone by!! Remember your 2nd semester grade is what you do at the end of the year. This 3rd quarter grade is an "in progress" grade. There is still time, 8 weeks, to improve your grade but you must make the effort. Start putting together your 'water project' teams if you have not. The water project is 50% lab and 50% assessment grade.

Lastly, have a great spring break

Week of 3/26/12

Chemistry and Physical Science

Monday- review for MSE
Tuesday- review for MSE
Wednesday- MSE
Thursday- MSE

Week of 3/19/12

Chemistry
Monday- review stoichiometry
Tuesday- stoich review or start nexttopic
Wednesday- computer lab, writing assignment
Thursday- stoich review/next topic
Friday- stoich quiz

Physical Science
Monday- volcanoes
Tuesday- Yellowstone video
Wednesday- Volcano activity, computer lab
Thursday- test review/activity
Friday- test, computer lab

Week of 3/12/12

Chemistry
Monday- start Ch 12, watch Kahn videos
Tuesday- practice problems
Wednesday- stoichiometry simulations, computer
Thursday- practice problems
Friday- stoichiometry simulations, computer

Physical Science
Monday- Miss B, watch Hawaiian Island formation lecture
Tuesday-review Boxer Tsunami, Epicenter activities
Wednesday- Hotspot activity, computer room
Thursday- review epicenter activities, hotspot
Friday- epicenter simulation, computer room

Stream Project- Physical Science

The Stream Project has been updated and is available on moodle under 'Stream Project". The Stream Characteristics Lab we will do in class.

Magnetic Reversal Lab - Physical Science

If you are having difficulty with the lab be sure to check your moodle. The Magnetic Reversal Lab key is located there.

Week of 3/5/12

Chemistry
Monday- prepare for ACT
Tuesday- ACT
Wednesday-MME
Thursday- Work Keys
Friday- bring donuts

Physical Science
Monday- spreading center activity/watch lectures in Earthquakes/Volcanoes by Friday
Tuesday- no school
Wednesday- San Andreas Fault Video, no computer room
Thursday-- Epicenter Activity
Friday- Boxing Day Tsunami Lab, computer room

San Andreas Fault/ Earthquakes

The above picture (credit USNP) is of the Carrizo Plain in which the San Andreas fault (think San Francisco earthquake of 1906) runs through this area. Using this area let's review some of the terms that pertain to earthquakes.

• a fault is where Earth movement has occurred due to a release of elastic rebound energy.
• the spot inside the Earth where the earthquake started is the focus, while the area directly above the focus on the Earth's surface is the epicenter.

The energy from an earthquake propagates as waves and can move the ground surface in any direction. There are three types of earthquake waves:

• surface waves- act like water waves and are the most destructive, slowest wave.
• p-waves- travel the fastest, push-pull (compressional) travel through solids and liquids.
• s-waves- slower than p-waves, transverse, can only go through solids.

Tsunamis are large ocean waves produces by movement of the ocean floor.
An earthquake's position can be determined by 3 seismic stations that contain an instrument called a seismograph. Scientists use the moment magnitude scale for measuring the strength of earthquakes.

Hotspots

A hotspot is a concentration of heat in the mantle that produces magma that reaches the Earth's surface. These hotspots can produce intraplate volcanoes. Intraplate volcanoes are those that occur within a tectonic plate and NOT on the plate boundary. The Hawaiian Islands were formed when the Pacific plate moved over a hotspot. The bottom picture is of Mauna Loa volcano in Hawaii. The volcanoes of Hawaii are broad domed-shaped volcanoes known as shield volcanoes.

The top picture is of Old Faithful geyser in Yellowstone National Park. Much of Yellowstone National Park is in a caldera- a large depression in a volcano. Yellowstone is an active geologic feature that lies over another intraplate hotspot. There is much conjecture that the Yellowstone area is due to erupt sometime in the future.

Volcanoes and Batholiths

Photo credits: top-Davis Spier, Earth Science World; bottom-R. Clucas, AK Volcano Observatory.

Let's look take a look at each of the above pictures.
The top picture of Mount Rushmore in the Black Hills of South Dakota is the result of an igneous feature called a batholith. A batholith is a very large igneous intrusion and these batholiths are associated with many of the major mountain ranges.

The middle picture of Crater Lake in Oregon was produced when the summit of a volcano collapsed. This depression is also known as a caldera.

The bottom picture is of Redoubt Volcano in Alaska. Redoubt Volcano is located on the Ring of Fire- a belt of volcanoes which surrounds most of the Pacific Ocean. Redoubt Volcano is known as a composite/stratovolcano . This type of volcano produces the most violent of volcanic eruptions.

Ocean- Continental Convergent Boundary

This type of convergent boundary also features a subduction zone (one plate descending beneath another plate). This boundary features an ocean trench and a continental volcanic arc.
As the ocean crust sinks/ subducts beneath the continental crusts, this ocean crust is destroyed. As the ocean crust is melted, forms magma, this magma can rise to the surface because the density of the magma is less than that of the rocks it was made from.

Continental-Continental Convergent Boundary

The best example of this type of boundary is what happened when the Indian landmass slammed into the southern edge of the Eurasian plate. The result of this collision formed the world's most famous mountain range - the Himalayans. These mountains are not volcanic as neither plate descends therefore very little magma is produced.

Transform Faults

This is a picture of the San Andreas Fault in California (photo credit:Wikipedia). A transform fault is a plate boundary where two plates grind past one another without destroying or producing new lithosphere. The lithosphere is the crust and upper part of the mantle.

Ocean-Ocean Convergent Boundary

A convergent boundary occurs when one plate descends (subduction) beneath another boundary due to a difference in density. The major features of this type of boundary is the ocean trench and a volcanic island arc. As the subduction plate descends earthquake foci increase in depth.
This ocean-ocean convergent boundary has produced many of the islands in the western Pacific Ocean.

Divergent Boundries

Let's look at divergent plate boundaries:

• mid-ocean ridges (pictures on left )- this is also known as seafloor spreading. At these boundaries new ocean crust is formed at an average rate rate of 5 cm per year. As one moves away from these ridges the crust cools, becomes denser and is older. As the seafloor spreads the age of the sediments that are on the ocean floor also increases. The top picture on left is a diagram of magnetic reversals. As the seafloor spreads and cools the magnetic rock particles align themselves with the magnetic poles of the earth. These reversals provide evidence for seafloor spreading.
  
• continental divergent boundaries (picture on right)- the Red Sea is an example of continental divergent boundaries. This is when a land mass splits apart.
• In both these examples magma pushes up through the lithosphere, volcanoes and volcanic activity is a product of these types of boundaries.
  

Wegener- The Continental Drift Man

Alfred Wegener proposed the theory of continental drift, (that all continents at one time were joined together as one) based on several pieces of evidence:

• the fit of the continents
• same type of rocks/ mountain chains on different continents
• fossils of the same organisms have been found on different continents
• the climates of the continents were different in the past than they are now.

These tectonics plates which consists of the upper mantle and crust move an average of 5 centimeters per year. The movement of these plates has been attributed to the convection currentsin the mantle.

Earth's Crust

The Earth's core is made of an alloy of iron and nickel. The mantle is most of the volume of the Earth and is a "plastic" like material. The thin, rocky outer layer of the the Earth is the crust. The ocean floor crust is basalt while the continental crust is mostly granite. The lithoshere is the crust and the upper mantle.