Week 10

     We begun Monday's lab by discussing what makes a rock a rock. While we sat on this question, we discussed the Activitymania article and how inquiry is long-term and process-oriented with the goal of student-led investigations, which is the opposite of what the Activiamania is. Turning towards assessment, we discussed the idea of grading based on growth instead of final understanding. Students should be rewarded for the effort they put in. Those students who understand enough often don't try to learn more, so they check out and make no progress. While this is not always a realistic way to assess students, it should definitely be taken into consideration. 

    When then bounced back to our inquiry of what makes a rock a rock. We discussed the three forms of rocks: igneous (melted then cooled), metamorphic (heated and pressed together), and sedimentary (cemented and compacted together). We used starbursts, a knife, tin foil, and a small blow torch to create two of each type of rock. Here were our results with sedimentary on the left, metamorphic in the middle, and igneous on the right:

    We picked up in lecture discussing how plate tectonics affect earthquakes and plate tectonics before moving on to how heat and pressure in the earth's core creates the three types of rock. We discussed how the rate of cooling of igneous rocks affect the end result. The longer it takes for the rock to cool, the less time similar elements have to find each other. Rocks with more noticable differences in different elements likely cooled over longer periods of time under the earth's surface, whereas rocks that are les recognizable cooled quickly, likely in the ocean. We moved on to the concepts of erosion and deposition. The strongest form of erosion is glacier, then water, then wind. They can cause either chemical erosion (combinations of different destructive chemicals) or mechanical (physically breaking rocks apart with pressure, exfoliation, or weathering). Finally, we finished with discussing the Law of Superposition and how new layers of rock continue to build on the earth's surface, so the deeper we go, the older the rock, and the older the species we will find. 

    Before this week's textbook reading, I had never understood what a hot spot was and how volcanoes could occur outside of plate boundaries. The Khan Academy videos were extremely useful in supplementing the lecture on Thursday explaining this and the formation of the Hawaiian Islands as well as other islands in the Pacific Ocean. The other thing I found extremely helpful was the explanation of the Law of Superposition and Law of Horizontality. We discussed these in lecture but the examples in the book as well as the Bozeman Science videos were great practice in identifying the ages of rock and what orders they were formed, including dykes.