Week 10: Convection and the Rock Cycle

 The big question this week was, What is the Rock Cycle and what causes it? 

In lab this week, we started by talkign about our reading, Activitymania. We talked about switching our mindset from having an Activity with a Worksheet, to an Investigation with a Guide Sheet. My big takeaway was that activities that have no practical applications, no connection to previous learning, and require no critical thinking on the students' part, are generally a complete waste of everyone's time. 

Then, we talked about assessment because we were going to be helping to set the curve later that day. We talked about how important formative and pre-assessments are. Without them, the final assessment means virtually nothing because you have nothing to compare it to. 

Then, we got started on our lab. We used Starbursts to make models of the three types of rocks. For Sedimentary rocks, my group decided to just squish the Starbursts together because the grater wasn't working. We recognized that this model wasn't super precise to how Sedimentary rocks actually form, but we did show two different levels of pressure. 

For Igneous rocks, we used the torch to heat both but poured water on one to have it cool much faster. It left some really cool bubble marks on the surface of the Starburst! The one that cooled slowly was flatter, and seemed more homogenous. 

For Metamorphic rocks, we heated them and then pushed on them with the smooth part of the grater to demonstrate heat combined with pressure. 


Model Intrusive (left) and Extrusive (right) Igneous rock

All three categories of rock, from top to bottom:
Sedimentary, Igneous, Metamorphic

Close-up of my lower-pressure
sedimentary Starbursts





Lecture
Below are my notes from what we talked about on Thursday: 
  • Layers of the Earth
    • Crust --> Mantle --> Core (Outer and Inner. The outer is liquid metal, inner is solid metal). 
    • We know what the layers are made of because of earthquake tracking and measurement. EQs move through solids differently than they move through liquids. 
  • Plate Tectonics
    • Continental plates are thicker
    • Oceanic plates are thinner, but MORE DENSE. 
      • Always subduct under the Continental plate. 
        • Creates trenches. 
    • When Continental plates hit another Continental plate, this creates mountains. 
    • When a Continental plate hits an Oceanic plate, this creates a trench because of subduction (sports car always loses in a crash with a semi truck). 
    • When two of the same plate move away from each other, magma is able to seep up. This is how you get volcanoes, and may cause hot spots like the one under where the islands of Hawaii formed. 
  • Hawaii is a Hot Spot
    • Hot Spot: weakness in the crust that constantly has a plume of magma. 
      • Oceanic crust drifts, so the magma eruption happens on new parts of the crust instead of the same spot. 
      • Erosion causes older eruptions to shrink after cooling. 
    • Ring of Fire: Highly active area with EQs and volcanoes along the Northern part of the Pacific plate. 
  • Rock Cycle
    • All rocks begin as magma that cooled. 
    • Igneous Rocks: "born from fire." 
      • Heat and pressure on Igneous rocks make them metamorphic. 
      • Extrusion from the Mantle, then weathering/erosion create Sedimentary rocks. 
    • Extrusive: exits the asthenosphere. Cools very quickly- small crystals (heat for less time, gave the minerals less time to clump with each other before solidifying)
    • Intrusive: inside the earth, and insulated. Creates larger crystals. 
    • Rocks can move through wind, water, or a glacier. 
      • Wind: moves/erodes only lighter materials
      • Water: causes the most damage, but cannot move as much at once as a glacier. Young rivers create V-shaped valleys
      • Glacier: can move more rock at once. 
Pressbook
  1. What did you learn?
    1. Effusive vs. Explosive eruptions- effusive eruptions occur slowly, where the magma flows out of a gap in the crust, while explosive eruptions occur very quickly and are highly pressurized so the magma and other contents tend to spray a further distance. 
    2. Volcanoes form at Convergent plate boundaries between an oceanic and continental plate, Divergent plate boundaries, or hot spots. 
    3. How do EQs occur? 
      1. Many causes, but most commonly occur at a transform boundary where two plates slide past one another but encounter "difficulty," which builds up pressure on a huge scale. When they finally break past, the breakage creates seismic waves which travel through the earth and cause earthquakes. 
    4. Within the law of superposition, we still have to consider things like intrusions, where magma seeps through layers of preexisting rock and solidifies as rock. These intrusions are always younger than the rocks they are "intruding" into. 
    5. Index fossils: fossils that are found in similar layers of rock in several places, allowing scientists to use them to figure out how old the rocks are. 
  2. What was most helpful?
    1. I think the diagrams were the most helpful in this reading. They really helped me to visualize what was being described. 
  3. What do you need more information on?
    1. I'm sure we'll get to this, but I'm curious about all the cool ways we could teach this stuff to kids!
  4. What questions/concerns/comments do you have?
    1. None I can think of!

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