Rocks and More

On Monday we continued with learning about rocks. We had previously started a new unit on them before Thanksgiving break but did a little reviewing before class just to make sure that we had a basic understanding. We then began to work on a new lab. This lab will help us learn more about different rock types and how to classify them. A big part in classifying rocks is by the way they are formed. Igneous rocks can be formed by two types of lava felsic or mafic magma. The difference between these two types is that one is more viscous than the other. One of the easiest texture to identify is the glassy rock texture. This rock has very sharp edges and is very shiny like glass. Another really cool rock type is pumice. This rock is very light and has many vesicles. Vesicles are holes that are forms in the rock because of pockets of gas that have formed inside the rocks. Due to all of these holes the rock is very light and can even float on water.

On Tuesday we continued with this lab and after finishing the lab I had a better understanding of intrusive and extrusive rocks. I also learned the slower the lava cools the larger the grains are. This is because they have more time to form. Fine grains are formed when lava is cooled quickly resulting in an extrusive rock.  To classify igneous rocks there are categories to help categorize them. Rocks can be classified by texture, color, intrusive, extrusive, minerals, and felsic of mafic. Lighter rocks have a lower density most of the time because they are very high in their silica content. Darker denser rocks, such as obsidian, are heavier because of their higher levels of iron.

On Wednesday we started to learn about metamorphic rocks. Metamorphic rocks are rocks that have been changed in some way from its original parent rock. For example bread changes into toast like metamorphic rock turns into a new form of rock. Metamorphic rocks can be categorized as foliated  or non-foliated. Foliated rocks have very distinct layers called bands. After notes we started a new lab on the classification of metamorphic rocks. This was like the igneous rock lab before although I did find naming the rocks a little easier in this lab.

On Thursday we reviewed notes mainly focusing on sedimentary rocks. Sedimentary rocks are formed from ground sediment that comes together over many years. Organic sedimentary rocks form from products from living organisms such as bones and shells. Chemical sedimentary rocks form from precipitates from water. After reviewing notes we started a new lab on sedimentary rocks. I have found sedimentary rocks to be harder to identify than igneous and metamorphic.

On Friday we continued with the sedimentary rock lab. I had a difficult time naming the rocks and that is something I need to improve on especially for the lab practical next week. We also have a quiz next Tuesday on everything we have learned so far with rocks. This lab helped me learn most of the basic concepts with rocks such as how each rock is classified.