Questions by students

Dear Gentlemen,

Below are questions asked by your schoolmates, you may look at them and see if they can also help you clarify some doubts.

I will update it constantly with any quesitons asked.

How are volcanoes formed? (Asked by Shawn, 1-5) [Chapter 8, answer in pg 84 of textbook]
1) Volcanoes are formed by the process of vulcanicity.
2) This usually happens when two plates collide with each other and where the denser plate will sink into the mantle and melt into magma due to the high temperatures.
3) The high temperatures also causes built up pressure of gases under the Earth's surface which leads to an eruption due to the release of this built up pressure of gases.
4) When the magma escapes to the Earth's surface through a single hole due to eruption, the cooler temperatures on the Earth's surface causes the lava to harden and solidify.
5) Overtime, with repeated eruptions, the hardened layers of lava results in a cone-shaped mountain called a volcano.

How do plates move? (Question in mini test and re-asked by Deon, 1-5) [Chapter8, answer explained in blog post and ink experiment video]

Plates lie/float on molten mantle.
Plates moves as the hightemperatures within the Earth surface causes the molten mantle to flow in certain directions due to convection currents.
Therefore, movements of the mantle cause the crustal plates that lie on it to move.

How are plateaux formed? (Question by Warren, 1-9) [Chapter 8, textbook pg 97]

1) Plateaux are formed by the process of vulcanicity.
2) This usually happens when there is a long crack or fault in the Earth's crust.
3) The high temperatures also causes built up pressure of gases under the Earth's surface which leads to an eruption due to the release of this built up pressure of gases.

4)Magma then escapes from a long crack or fault and spreads over a very large area, the cooler temperatures on the Earth's surface causes the lava to harden and solidify.

5) Overtime, with repeated eruptions, the hardened layers of lava results in a plateau.

*Process is the same as volcano, just that instead of a single hole vent, its a large LONG crack or fault.

Chapter 9: Rocks

Hi Gentlemen,

My apologies for the late post of videos on the Chapter 9. But as you prepare for your class test this Saturday, please go through the videos below if you still have any queries or aren't sure of some concepts.

Here's the video I showed you during class, when I wanted to introduce to you the three different rock types and the rock cycle. It's really a good visual re-cap of the whole chapter itself. You can watch the video until 1.24 minutes as after that it is not relevant, but more for general knowledge.

The next few videos are quite old videos but quite good in knowing in details the different rocks.

IGNEOUS ROCK

Here's a video that shows you how to identify igneous rocks..

SEDIMENTARY ROCK

Here's a video about the Grand Canyon and how it is made up of mainly sedimentary rock, for your interest. =)

METAMORPHIC ROCK

Finishing it off, is this rock cycle video I showed you in class, go through the animation and in your mind have the thought process of what the rock cycle is about.

This can be found at http://www.geolsoc.org.uk/gsl/site/GSL/lang/en/page3892.html too.