Earth Structure and Plate Tectonics

1. 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

2. What is this?  Digital Vision 9 (NT)

3. WALT What is the structure of the Earth? WILF All 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 )

4. Starter • Which metals are found at the centre of the Earth? • How thick is the Earth’s crust? • How were the Himalayan mountains formed? • Where do we find volcanoes? • Why do earthquakes happen? • Who is Wegener?

5. Key Words Core crust mantle convection currents tectonic plates continental drift

6. The Earth’s Structure Beneath the atmosphere the Earth consists of 3 main layers:

7. The Structure of the Earth A 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 solid The average density of the Earth is much higher than the crust, so the inner core must be very dense

8. What am I? • 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. Inner core Outer core Crust Mantle Atmosphere

9. 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 )

10. Tectonic plates • The crust is made of about twelve plates. • 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.

12. Movement of the Lithosphere 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. crust The Earth’s LITHOSPHERE (i.e. the _______) is split up into different sections called ________ plates: tectonic year convection radioactive Words – radioactive, crust, convection, tectonic, year

13. 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 )

14. Continental Drift

15. Introducing plate tectonics

16. Jig Saw fit Similar rocks and fossils 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!

17. 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

18. WALT What is the structure of the Earth? WILF All 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 )

19. Plate boundaries

20. Activity • 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