Earth Structure and Plate Tectonics

By the end of this lesson you will:• Know the structure of the Earth’s

interior• Understand plate tectonics and

their movement

What is this?

Digital Vision 9 (NT)Digital Vision 9 (NT)

WALT What is the structure of the Earth?WILFAll students are able to recall the structure of the

Earth ( grade D )Most students are to describe what are tectonic plates

and how they move by convection currents ( grade C )Some students are able to explain continental drift

and what happens at plate boundaries ( grade B )

Starter

1. Which metals are found at the centre of the Earth?

2. How thick is the Earth’s crust?3. How were the Himalayan mountains

formed?4. Where do we find volcanoes?5. Why do earthquakes happen?6. Who is Wegener?

Key Words

Core crust mantle

convection currents tectonic plates

continental drift

The Earth’s Structure

Beneath the atmosphere the Earth consists of 3 main layers:

The Structure of the EarthA thin crust - 10-100km thick

A mantle – has the properties of a solid but it can also flow

A core – made of molten nickel and iron. Outer part is liquid and inner part is solidThe average density of the Earth is much higher

than the crust, so the inner core must be very dense

• I am dense, very hot, made mostly of solid iron and nickel.

• I’m iron and nickel too, but I’m liquid.

• I’m really very thin and am mostly silicon, oxygen and aluminium

• I’m a viscous semi-solid with convection currents circulating in me.

• I just hang around on the outside. Atmosphere

Outer core

Crust

Mantle

Inner core

What am I?

How am I doing?

Were you able to answer the questions?

YES ? Well done you have achieved WILF 1

All students are able to describe the structure of the Earth ( grade D )

Tectonic plates

• The crust is made of about twelve platesplates.• These are like big rafts floating on the semi-molten

mantle.• Convection currents within the mantle cause the

plates to move.• Although they only move about 2 cm/year this can

have huge effects over long periods of time.

Movement of the LithosphereThe Earth’s LITHOSPHERE (i.e. the _______) is split up into different sections called ________ plates:

These plates are moving apart from each other a few centimetres every _______ due to the ________ currents in the mantle caused by the ________ decay of rocks inside the core.

Words – radioactive, crust, convection, tectonic, year

crusttectonic

yearconvectionradioactive

How am I doing?

Were you able to complete the sentences?

YES ? Well done you have achieved WILF 2

Most students are to describe what are tectonic plates and how they move by convection currents ( grade C )

Continental Drift

Introducing plate tectonics

Evidence for Continental Drift

The theory is supported by several pieces of evidence. For example, if we consider Africa and South America there is:

– The “jig-saw fit” – The similarities in the rock layers

from Africa and South America.– Similarities in the type and age of

fossils.– Evidence of related species that

definitely did not swim the Atlantic Ocean!

Jig Saw fit

Similar rocks and fossils

Task

Working in a pair

Write your own explanation for plate tectonics and continental drift using the information given to you by your teacher and text book

Include a section on what evidence is available to support the idea of continental drift

WALT What is the structure of the Earth?WILFAll students are able to recall the structure of the

Earth ( grade D )Most students are to describe what are tectonic

plates and how they move by convection currents ( grade C )

Some students are able to explain continental drift and what happens at plate boundaries

( grade B )

Plate boundaries

• Find the words and write a sentence about how each one has something to do with plate tectonics.

– Drift– Earthquake– Fossil– Jigsaw– Magma– Pangaea– Plates– Subduct– Volcano

K G F N Z P D C L EL F O Q A P C X K EE M S V O L C A N OI X S U B D U C T AD R I F T Q J S M WM K L Q H S I A W FP L A T E S G K E NZ V R Q A M S P F XP A N G A E A P V AE V R A D G W L I S

Activity