Draw a cross section of the earth and label it with the correct names and characteristics crust - relatively thin and rocky (Oceanic 30-50km and continental.

Draw a cross section of the earth and label it with the correct names and characteristics

crust - relatively thin and rocky (Oceanic 30-50km and continental 6-8km) - LITHOSPHERE! mantle - has the properties of a solid, but can flow very slowly 35 - 2900 km, 900-1600 oC – ASTHENOSPHERE outer core - made from liquid nickel and iron 2900-5270km, 4000-5000 oC inner core - made from solid nickel and iron

How is the earth heated? Where does the heat come for

the convection currents?

Radioactive decay of uranium in the core raises the temperature to over 5000oC

Heat moves from the core to the surface in plumes. These bring magma to the surface

Magnetic field

The Earth also has a magnetic field as a result of the outer core – the liquid iron acts as an electric dynamo and produces the field

This field protects us from the sun’s harmful radiation

Plate boundaries

Typical exam question: (4Marks)

Explain why earthquakes happen on destructive plate margins. You may draw a diagram to help your answer.

What are the commands in this question?Have a go!

What did you get?

A Destructive margin is where 2 plates collide. One plate is sub-ducted under the other one. Usually a oceanic plate is sub-ducted under a continental plate. There is friction between the two plates. The pressure builds and eventually gives way, The energy release is the land shaking, called an earthquake.

A* answer

I find diagrams easier thanWriting…. Draw a labelled

Diagram to help answer the Q

Constructive Plate Boundary

Name this plate boundary.

Continental crust MantleThe oceanic crust melts and risesExplosive volcanoes

Oceanic plate

The oceanic crust sinks under the less dense continental crust Earthquakes occur due to friction

Match the labels to the letters

A B

C D

E

F

G

• Named Continents• Named Plates

• Use of Keywords• Clear Descriptions• Clear Explanations

Volcano types

• Watch the video and sketch the different types of volcano with their characteristics

• http://www.youtube.com/watch?v=sl5Id6wRSeU&NR=1

• There are 3 different types of volcanoes:• Active - eruptions can be anytime and often. • Dormant - has been a while since it has

erupted, but could at anytime. • Extinct, meaning it hasn't erupted in a very

long, long time so it probably won't ever again.

Pyroclastic flow

• fast-moving current of superheated gas • can reach temperatures of about 1,000 °C • rock which reaches speeds moving away from a

volcano of up to 700 km/h

Lava flow • Lava is molten rock that flows out of a volcano • Depending on its composition and

temperature, lava can be very fluid or very sticky (viscous).

• Fluid flows are hotter and move the fastest; they can form streams or rivers

Cinder cone volcanoes

Cinder cones build from lava that is blown violently into the air and breaks into fragments. As the lava pieces fall back to the ground, they cool and harden into cinders (lava fragments about ½ inch in diameter) that pile up around the volcano's vent. Cinder cones are the smallest volcanoes and are cone-shaped.

• Where are volcanoes located? Volcanoes are found along destructive (subducting) plate boundaries, constructive (divergent) plate boundaries and at hot spots in the earth's surface.

• What is the Ring of Fire?A volcanic chain surrounding the Pacific Ocean. It is formed along a destructive (subducting) plate boundary.

• What are lahars and pyroclastic flows?The most destructive aspect of volcanoes are lahars and pyroclastic flows.

• Lahars are volcanic mudflows created when water (from rain or melt water from glaciers) and ash mix. This deadly combination can have devastating results on the surrounding area. When lahars settle they can be metres thick and as hard as cement. Lahars can occur long after a volcanic eruption.

•Pyroclastic flows are avalanches containing hot volcanic gases, ash and volcanic bombs. On steep volcanoes pyroclastic flows can reach speeds of over 100 miles per hour.