Candy Bar Plate Tectonics Marie Saxon 2015

What are the layers of the Earth?

Compare the parts Chocolate= Carmel= Nougat= Peanuts=

Compare the parts Chocolate=Earth’s Crust/lithosphere Carmel=asthenosphere Nougat=core Peanuts=convection currents

Crust Composition-rocky, sediments. It contains more silica than the mantle Continental crust: granite, O, Si, Al Oceanic Crust: Basalt, Ca, Fe, Na, K, Mg Temperature-same temperature as the air. So, it may be as hot as 35 degrees C in the desert and below freezing in Antarctica. If you dig down, the temperature goes up. Thickness-very thin, just 5-70 km.

Mohorovicic Discontinuity The Mohorovicic Discontinuity, or "Moho", is the boundary between the crust and the mantle. The red line in the drawing at right shows its location. In geology the word "discontinuity" is used for a surface at which seismic waves change velocity.

Mantle Semisolid, molten rock. It flows very slowly, like hot asphalt. This layer is made of O, Si, Al, and Mg. lithosphere-83% of earths volume (rigid) asthenosphere (molten plastic) Temperature-870-3700 degrees F. Thickness-2900 km thick

Gutenberg discontinuity The Gutenberg discontinuity occurs within Earth's inerior at a depth of about 2,900 km (1,800 mi) below the surface, where there is an abrupt change in the seismic waves (generated by earthquakes or explosions) that travel through Earth.

Outer core Composition-made of thick liquid Fe and Ni Temperature-3700-4300 degrees F Thickness-200 m thick

Inner Core Composition-solid ball of iron and nickel Temperature-4300-7200 degrees F Thickness-1250 km thick Both outer and inner core take up 1/3 of Earth’s Mass

Gutenberg discontinuity

Plates The Earth’s crust is divided in large pieces called plates.

Plates Play plates moving

Plate Tectonics Snicker’s Lab Background Info: Plate tectonic is the theory that the lithosphere is divided into tectonic plates that move around on top of the asthenosphere. Tectonic plate boundaries are divided into three types: convergent, divergent, and transform.

The type of boundary depends on how the tectonic plates move relative to one another. Tectonic plates can collide with, pull away from or slide past each other. One possible driving force of tectonic plate movement is the process of convection within the asthenosphere.

The slow movement of the solid rock in the asthenosphere is caused by density changes. Density changes are caused by the outward flow of thermal energy from deep within the Earth.

When rock is heated, it expands, becomes less dense, and sinks back down. This process of convection within the asthenosphere is believed to drive the tectonic plates above it to move relative to the convection currents below.

The chocolate represents the Earth's crust and the filling represents the asthenosphere.

Use your fingernails to break up the chocolate crust

What type of strain occurred due to the stress placed on the “crust” by your fingernail?

Faulting http://faculty.icc.edu/easc111lab/labs/labg/fault/normal_fault.html

Faults Cracks in the Earth’s surface along which rocks move are called faults.

Slowly and gently pull on the edges of the candy bar.

What type of tectonic plate boundary does the action represent?

Divergent Play divergent fault Play fault block mountains

Tension (Diverging Boundary) Is a force that pulls on the plates of Earth’s crust causing them to move apart. Play

What landforms occur at this type of tectonic plate boundary? Volcanic mountains, fault block mountains, magma, and rift zone

Fault block mts in Sierra Nevada

Observe the candy bar Re-draw the candy bar (“birds-eye-view”) and label: 1. Volcanic mountains 2. Fault block mountains 3. Magma 4. Rift zone 5. Arrows to show plate movement

Now push the “plates” back together, then slowly and gently slide (horizontally) one half towards you and the other half away from you

What type of tectonic plate boundary does this action represent?

Transform or stike-slip Play transform fault

What results from this type of tectonic plate boundary?

Faults and Earthquakes Play how an earthquake happens

Shearing (Transform boundary) Is the force that pushes on the plates of Earth’s crust causing one to more in one direction and the other plate I the opposite direction. Play

Re-draw the candy bar (“birds-eye view”) and label: 1. Fault 2. Earthquake epicenter 3. Arrows to show plate movement

Re-align the “plates” so that they are together again Re-align the “plates” so that they are together again. Now slowly and gently push on both ends of the candy bar to squeeze it together.

What type of tectonic plate boundary does this action represent?

Convergent Play for convergent boundaries

What landforms occur at this type of tectonic plate boundary?

Converging boundaries Continent-continent (continental mountains) Continent-ocean and ocean-ocean (volcanic mountains)

Compression (Converging boundary) Is a force that pushes on the plates of Earth’s crust causing them to move together. Play

Re-draw the candy bar (side-view) and label: 1. Type of mountains based on “crust” 2. C/C, C/O, O/O 3. Subduction zone

All three forces:

All forces

Show all forces Play all forces