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(credit to rightful artist.)
Not all rocks are the same. There are big rocks & small rocks, short rocks and TALL rocks. One rock, two rock, red rock, blue rock. You get what I mean. Metamorphically speaking, you shouldn't take rocks for granite. (Get it haha I'm hilarious.)
All jokes aside, let's talk about rocks. (I actually got these puns off the internet, guys. I'm not that punny. I apologize.)
Not all rocks are the same. There are big rocks & small rocks, short rocks and TALL rocks. One rock, two rock, red rock, blue rock. You get what I mean. Metamorphically speaking, you shouldn't take rocks for granite. (Get it haha I'm hilarious.)
All jokes aside, let's talk about rocks. (I actually got these puns off the internet, guys. I'm not that punny. I apologize.)
There are three types of rock: Igneous, Metamorphic, and Sedimentary. Unless you are a geologist, identifying a rock into one of these three categories can be difficult.
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Igneous rocks form when magma/lava cools and hardens. The rock will either form from magma cooling inside the earth or form by the lava erupting to the surface from volcanoes and cooling. If the lava were to cool very quickly, the rock would form to be very shiny and glass-like as a result. An example for such a rock would be obsidian. Gas bubbles can become trapped in the rock while it is cooling, leaving tiny holes and spaces in the rock as a result. Did you know that around 95% of the upper section of the earth's crust is made of igneous rock?!
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Metamorphic rocks form underneath the surface of the earth. They form from the metamorphosis (change) that happens because of extreme heat and pressure. This process often creates rocks with ribbon-like layers and may have shiny crystals. These crystals are formed because of minerals slowly growing as time goes by. Uplift and erosion causes metamorphic rocks to rise to the surface of the earth. Did you know that metamorphic rocks can begin to form at 12-16 kilometers underneath the surface of the earth?!
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Sedimentary rocks form over a long period of time. They are made of particles and pieces of older rocks such as sand, shells, pebbles, and other materials. All of these particles combined together are called sediment. Over time, this sediment will accumulate in layers and harden to become sedimentary rock. In general, this type of rock is quite soft and will crumble and break easily. While observing a sedimentary rock, you may most likely see sand, pebbles, stones, or possibly even fossils in the rock. Did you know that table salt is a type of chemical sedimentary rock?!
These rocks obviously don't come from nowhere. Rocks can form from other rocks and can even form from the same type of rock. It is a whole group of changes when it comes to the rock cycle; it never really stops. There are five different ways a rock can form into a different rock: Heat and Pressure, Melting, Weathering and Erosion, Compacting and Cementing, and Cooling.
That concludes this post about rocks. When it comes to geology, leave no stone unturned! (Yeah, I got that off the interent, too.)
~ Joanna Koh
~ Joanna Koh
Bibliography:
ReferencesArchive.d83.org, (2014). igneous. [online] Available at: http://archive.d83.org/Teachers/dukhan/4thgrade/rocksminerals/metam.html [Accessed 30 May. 2014].
Learner.org, (2014). Interactives . The Rock Cycle . Introduction. [online] Available at: http://www.learner.org/interactives/rockcycle/index.html [Accessed 30 May. 2014].
Sciencekids.co.nz, (2014). Igneous Rock Facts for Kids - Information & Examples. [online] Available at: http://www.sciencekids.co.nz/sciencefacts/earth/igneousrocks.html [Accessed 30 May. 2014].
Sciencekids.co.nz, (2014). Metamorphic Rock Facts for Kids - Information & Examples. [online] Available at: http://www.sciencekids.co.nz/sciencefacts/earth/metamorphicrocks.html [Accessed 30 May. 2014].
Softschools.com, (2014). Sedimentary Rocks Facts. [online] Available at: http://www.softschools.com/facts/rocks/sedimentary_rocks_facts/367/ [Accessed 30 May. 2014].
ReferencesArchive.d83.org, (2014). igneous. [online] Available at: http://archive.d83.org/Teachers/dukhan/4thgrade/rocksminerals/metam.html [Accessed 30 May. 2014].
Learner.org, (2014). Interactives . The Rock Cycle . Introduction. [online] Available at: http://www.learner.org/interactives/rockcycle/index.html [Accessed 30 May. 2014].
Sciencekids.co.nz, (2014). Igneous Rock Facts for Kids - Information & Examples. [online] Available at: http://www.sciencekids.co.nz/sciencefacts/earth/igneousrocks.html [Accessed 30 May. 2014].
Sciencekids.co.nz, (2014). Metamorphic Rock Facts for Kids - Information & Examples. [online] Available at: http://www.sciencekids.co.nz/sciencefacts/earth/metamorphicrocks.html [Accessed 30 May. 2014].
Softschools.com, (2014). Sedimentary Rocks Facts. [online] Available at: http://www.softschools.com/facts/rocks/sedimentary_rocks_facts/367/ [Accessed 30 May. 2014].