Starter ActivityStarter Activity

On a piece of paper quickly On a piece of paper quickly draw a cross section of an draw a cross section of an

apple, peach or egg to apple, peach or egg to show the different layersshow the different layers

Key Ideas we’ll be covering in this Key Ideas we’ll be covering in this unit:unit:

–How and why do Earth’s tectonic plates move?

–What are the effects and management issues resulting from tectonic hazards?

Today’s Learning Objectives:Today’s Learning Objectives:1.What is the structure of the Earth? 2.What evidence can we use to work

out what the layers of the Earth are like?

c/w 27th January

Convection Currents

Inside the Earth, the source of the heat is the extremely hot core. This heat from the interior rises toward the surface of the Earth. It causes liquid rock in the mantle to move with it.

Hot and less dense liquid rock moves upward. Cool heavy rock sinks downward. This circular movement of matter is known as convection. Convection occurs within the liquid rock of the lithosphere’s mantle.

http://education.sdsc.edu/optiputer/flash/convection.htm

• Scientists believe that convection in the mantle is the reason why the crustal plates move. The plates ‘ride’ on convection currents. The plate motions, of course, result in volcanoes, earthquakes and mountain building. Convection caused Pangaea to break up. The convection currents pushed the continents to where they are today.

Plate movements have led to continental drift. 225 million years ago all the land masses were fused to form a super-continent - Pangea.

200 million years ago Pangea began to move apart to form two great land masses - Laurasia and Gondwanaland.

About 135 million years ago it was possible to make out land masses that looked more like those we see today.

For example it is possible to see how South America and Africa were drifting apart to form separate continents.

Pangea has now separated to form the Pangea has now separated to form the continents we know today.continents we know today.

The continents are made of “continental The continents are made of “continental

crust” and the oceans rest on “oceanic crust”.crust” and the oceans rest on “oceanic crust”.

But what are the thick black lines?

Direct Evidence that the Earth is structured in layers

This is evidence that can be seen on the Earth’s surface

For instance rock samplesAnother example is volcanic evidence,

such as volcanic gases and volcanic materials

This is evidence which comes from sources outside the EarthFor example, meteorites come from space but may be like rocks found at the

centre of the Earth (in the core)Earthquakes also help us understand the structure of the Earth. For example, patterns produced by earthquake waves indicate there are differences in the composition of the centre of the Earth

Indirect Evidence that the Earth is structured in layers

Class WorkRead Pages 8-10 in the green textbook.Use the information from these pages to complete the boxes on the A3 factsheet

Homework

Due next lesson Obtain a detailed cross section of the earth labelled with all the

key words. Include: distances, temperatures, names, etcYou may search on Google for this but make sure you

customise it to meet our needsComplete the convection currents diagram box on the right of

the sheet using p12 of your purple textbook.

Key VocabularyLithosphere Tectonic PlatesAsthenosphere Continental CrustOceanic Crust MantleOuter Core Inner CoreMeteorites GraniteBasalt

TASKSelect 4 words from the list but one has to be an “odd oneout”. Swap the 4 words with a friend. See if they can tell which is the odd one out. Get them to give a reason why it doesn’t match!

Key IdeasThe Earth is composed of layers with distinguishing

characteristicsThe Earth’s crust is divided into the continental and oceanic

crustThe crust can be identified by different types of rock: granite

and basaltThe asthenosphere has an important role in the movement of

tectonic platesEarthquake waves help us to understand the different

characteristics of the layers of the earthMeteorites help us to understand what the Earth’s core is

made of

How well can you...Define or explain today’s Key Vocabulary?Describe the different layers of the interior of

the Earth?Explain what evidence supports the theory

that the Earth is structured in layers?Understand the difference between direct

and indirect evidence?