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TA Notes, Third Lab (Igneous Rocks), 1405 The Dynamic Earth, Fall 2017

This information is confidential, intended only for the Geology 1405 teachers
Revised 9:40 AM, 12 September 2017

Before the lab begins...

Check to be sure that the lab is in good condition, that the correct specimens are in the labeled boxes (students sometimes switch the specimens so that the labels and the specimens no longer go together), and that everything is ready for the lab.

Direct students to put their coats, backpacks, longboards or other paraphernalia that is not essential for the lab along the edges of the lab room. Keep the emergency exit clear.

As the students are coming into the classroom, consolidate them into groups of ~3-5 folks around a given table. When all the students are in the room, the groups should have approximately equal numbers of students in them.

The Teacher's Lab Outline

It is ESSENTIAL that you get through the introductory stuff with all deliberate speed
so that students have enough time to complete the lab activities.
  1. When the start time of the lab is reached...
    1. Distribute copies of the determinative tables to help students identify igneous materials
    2. Tell them that the goals of this lab are...
      1. help them learn how we can identify igneous materials (rocks and glass) based on their physical properties, and
      2. help them prepare for the mineral and rock quiz that will occur in a few weeks.
    3. Tell them that we will be spending the whole period working on Activities 5.2, and 5.4-5.7 in the lab book.
    4. Quickly walk around the room and briefly point-out the labeled specimens, displays, and optional activities that students should make use of.
      1. The "float the pumice" display. Demonstrate taking a piece of pumice, placing it in the water to show that it floats, and them removing it from the water and placing it onto the paper towel so that it will dry.
      2. The igneous rock twins (granite & rhyolite, diorite & andesite, gabbro & basalt)
      3. Obsidian and de-vitrifying obsidian
        Remind them that the specimens of obsidian in the lab are actually pieces of broken glass, so they should be handled with care.
      4. Graphic granite
      5. Volcanic bombs
      6. Llanite -- an igneous rock (rhyolite?) with blue quartz that is only found in the Llano area of Texas
      7. A sample of ash-fall tuff and a photo of pyroclastic breccia
    5. Students should be encouraged to use the displays around the room along with information they read in the tables in the book to help them identify minerals.

  2. Briefly introduce what each group will be doing, using words like the following:

  3. Then get them started on their activities.

  4. Determine the timing of the activities, and write the switch times on the front and back boards

  5. With 10 minutes left in the lab session (or when everyone has finished the activities), administer the post-lab survey. Announce that this post-lab survey is to be completed by each student individually, without assistance from any other student. It is a closed-book, closed-note quiz.

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