lesson-1-grade-10scienceeeeeeeeeeeee.pptx

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1. Why do earthquakes happen?

2. WHY DO EARTHQUAKES HAPPEN? Caused when rock underground suddenly breaks along a fault. Moving of crustal plates. Volcanic Activity

3. LAYERS OF THE EARTH

4. Layers of the Earth The earth is made up of layers. The crust- Is made from solid rock. The mantle- Is made of magma. Outer Core- Is made of liquid iron and metal Inner Core- Is made of solid iron and metal

5. EARTH’ LITHOSPHERE ✔️ C onsists of layers, the crust and the upper part of the mantle.

6. The Crust ✔️ The outermost layer of the Earth. ✔️ Thin compared to other Earth layers (mantle and core). ✔️ Made up of solid rocks and minerals .

7. The Crust M ade of a variety of solid rocks

8. The Crust M ade of a variety of solid rocks

9. The Crust M ade of a variety of solid rocks

10. Crust Density: About 2.8 g/cm³ ✔️ Thickness Range: 5 to 50 km ✔️ Thickest Part: Under mountain ranges (up to 70 km in some cases) ✔️ Thinnest Part: Under the ocean floor (as thin as 5 km)

11. The Crust This is where we live! The Earth’s crust ✔️ Continental Crust ✔️ Oceanic Crust

12. CONTINENTAL CRUST ✔️ Forms the land we see today ✔️ Thicker than oceanic crust: Average thickness: 35 km Under mountains: can reach up to 70 km ✔️ Less dense than oceanic crust → it floats higher on the mantle (more buoyant). ✔️ Contains some of the oldest rocks on Earth (up to 4 billion years old).

13. OCEANIC CRUST thin (6-11 km). ✔️ Oceanic Crust is heavier and denser than Continental Crust . ✔️ When these two crusts collide (at a convergent plate boundary), the denser oceanic crust sinks beneath the continental crust. ✔️ This process is called subduction . The rocks of the oceanic crust are very young compared with most of the rocks of the continental crust. They are not older than 200 million years.

14. ✔️ The lithosphere (Earth’s outer layer) moves slowly but continuously. ✔️ Arctic Ridge , move the slowest (below 2.5 cm/year ). ✔️ East Pacific Rise , move the fastest (over 15 cm/year ). ✔️ This movement is called tectonics . LITHOSPHERE

15. ✔️ Arctic Ridge , move the slowest (below 2.5 cm/year ). ✔️ A ridge is a long, narrow elevated area found on land or under the ocean .

16. ✔️ East Pacific Rise , move the fastest (over 15 cm/year ).

17. PLATE TECTONICS

18. PLATE TECTONICS The Earth's crust is broken into big pieces called tectonic plates . ✔️ These plates are always moving — but very slowly.

19. ✔️ Their motion causes them to do three things: Collide (Converge) plates push against each other. Pull Apart (Diverge) plates move away from each other. Scrape Past (Transform) plates slide side by side. PLATE TECTONICS

20. Each of these movements makes different Earth features like: Mountains (from collisions) Rift valleys or mid-ocean ridges (from pulling apart) Fault lines and earthquakes (from sliding past) PLATE TECTONICS

21. PLATE TECTONICS

22. PLATE TECTONICS

23. PLATE TECTONICS

24. ✔️ The word "tectonic" means how the Earth's crust changes shape or gets deformed because of these plate movements. PLATE TECTONICS

25. Where do tectonic plates float? ✔️ ASTHENOSPHERE A layer of the upper mantle found below the lithosphere . ✔️ Soft, hot, and partially melted (plastic-like) — rocks here can flow slowly .

26. Where do tectonic plates float? ASTHENOSPHERE ✔️ The lithosphere "floats" and moves on top of this layer. ✔️ Responsible for the movement of tectonic plates (plate tectonics). ✔️ This allows the plates to slide and move slowly in different directions causing earthquakes, mountains, volcanoes, and ocean trenches.

27. Where do tectonic plates float? ✔️ This allows the plates to slide and move slowly in different directions causing earthquakes, mountains, volcanoes, and ocean trenches.

28. ACTIVITY TIME!