Natural Hazards and Disasters – Chapter 7 Geography NCERT class 11

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1. Batch 2024 – 2025

2. Thanks

3. Some unusual noise is coming continuously from the video

4. ❤

5. ❤

6. Love the ending❤😅
   peace

7. Thank you very much sir .ur videos improved my confidence to write my exams

8. A huge thank you.. These wonderful videos saved a lots of time, An incredible job sir🎉 Thank you again. 😊

9. Very nice explanation ❤

10. thank u sir

11. Thanku so much sir bhut jyda dar lag rha tha but you solved everything thankyou again sir

12. 🖤🖤

13. Thanks sir can you support us in 12 class also it may help us a lot

14. I'd like to add something to Biological hazards please…

15. The movement of plates at the Earth's surface is driven by the convection of material in the mantle, which is the layer of the Earth between the crust and the core. Convection occurs when heat is transferred from one place to another by the movement of a fluid, in this case, the semi-solid mantle rock.

    The mantle is heated by the core at the bottom, and this heat causes the mantle rock to become less dense and rise towards the Earth's surface. As the mantle rock rises, it cools and becomes more dense, causing it to sink back down into the mantle. This cycle of rising and sinking creates a continuous flow of material in the mantle, which drives the convection of the mantle.

    The movement of the mantle causes the plates at the Earth's surface to move as well. The plates are rigid and float on top of the mantle, so as the mantle moves, it carries the plates with it. The movement of the plates is influenced by several factors, including the shape and size of the plates, the presence of ridges and trenches, and the forces generated by the mantle convection.

    In the case of plate tectonics and the theory of seafloor spreading, the mantle convection drives the movement of the oceanic plates away from the mid-ocean ridges, causing the ocean floor to expand and the ocean basins to grow. This process has been ongoing for millions of years, and it is one of the key mechanisms by which the Earth's crust has changed and evolved over time

16. Seafloor spreading is a key concept in the theory of plate tectonics, which explains how the Earth's crust is composed of large plates that move and interact with each other. The theory of seafloor spreading states that new oceanic crust is formed at mid-ocean ridges and is then moved away from the ridge in opposite directions.

    Here's how the process of seafloor spreading works in detail:

    Formation of magma: Magma rises to the Earth's surface at mid-ocean ridges, which are long, underwater mountain ranges that run along the ocean floor. The magma cools and solidifies to form new oceanic crust.

    Movement of plates: As the new oceanic crust is formed at the mid-ocean ridge, the existing crust on either side of the ridge is pulled away from the ridge and moves in opposite directions. This movement of the plates is driven by the convection of material in the mantle beneath the Earth's crust.

    Expansion of the ocean floor: As the plates move away from the mid-ocean ridge, the ocean floor expands, causing the ocean basin to grow. This process of ocean floor expansion has been going on for millions of years, and has resulted in the ocean basins that we see today.

    Evidence for seafloor spreading: The theory of seafloor spreading has been supported by a variety of geological and geophysical evidence, including the presence of magnetic stripes on the ocean floor, the shape and structure of mid-ocean ridges, and the ages of oceanic crust as determined from radiometric dating.

    In summary, the theory of seafloor spreading explains how new oceanic crust is formed at mid-ocean ridges and is then moved away from the ridge in opposite directions, causing the ocean floor to expand. This process is a key part of the plate tectonic theory, which explains how the Earth's crust is composed of large plates that move and interact with each other.

17. Thanks 👍 sir

18. Bro ended this chapter in 17min my teacher took 5days to complete this chapter without knowing that nobody is understanding him >:( Thanks sir lot of love 💕❤️ may god fulfill your desire or wishes

19. Commendable !

20. Love Ur efforts . Very slouble form u taught.. Love U Sir 🙏🙏🙏

21. Thanks 💜

22. 6 yrs ago and still feels like new vedio

23. thanks a ton

24. great👍👍👍

25. Sir how to get pdfs please tell

26. Sad to see that there is only always 7 sisters and no brother in North East India. Sikkim a forgotten state lol. 😂

27. Thank you❤🌹🙏 sir, this class is more important also for me Master of Disaster Studies

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