Astronomy Week 4

This week’s theme was the geology of the Earth and how it influences life on Earth.

I have to admit, this is NOT my specialty, and I had to do a lot of learning myself to understand some of the concepts. This worried me, but just by luck, our Pedagogical Reading Group was reading a chapter in Teaching What You Don’t Know by Therese Huston about teaching & surviving. It at least gave me the realization that I’m not the only one sometimes teaching outside my specialty.

Learning Outcomes for Week 4

By the end of this lesson, students should be able to describe the following to a general audience:

  • How geology is crucial to life on Earth
  • What information can be learned from rocks & fossils
  • How Earth got its oceans and atmosphere
  • What the interior of Earth is like
  • The basics of Earth’s climate
  • How the moon was formed

As per usual, we started off with a  Kahoot review of the 5 worst quiz question from the week before. Then, I notes some cool things going on in Space news recently: 9th Planet and 5-planet alignment.

We began lecture with a think-pair-share where I asked the students to discuss what does Earth have that other terrestrial planets don’t. We came up with a list that I projected on screen.

I introduced and briefly summarized the 3 major geological factors that aid life on Earth: volcanoes, plate tectonics and the magnetic field.

Then we went into the geological record – what rocks and fossils can tell us. I’ll admit that I stumbled around a bit in this section. I’m not sure how my explanation of half-life came across. One thing I need to remember is this is a first-year survey course, they DO NOT NEED a PhD-level explanation of everything. I think keeping this in mind will ease some of my anxiety about topics I don’t know so we.

We then went on to talking about what Earth was like during the Hadean Eon: 1) how it was most likely outgassing from volcanoes that created the atmosphere and oceans and 2) how the Earth (and all other planets/moons) was bombarded by asteroids and comets. Taking #2 further, we talked about what information we can get from looking at the numbers and sizes of craters on a planetary body (age of the surface!). Here I gave them the opportunity to take on a crater-counting activity for participation marks.

At this point we went on to discuss the layers of the Earth (you bet your butt that I play the Layers of the Earth song for them!), plate tectonics (and how its unique to Earth in our Solar System, and how it regulates climate), and the magnetic field (and how it protects us from solar radiation and helps retain the atmosphere).

Here we went on to talk about how Earth regulates its climate through the Greenhouse Effect and the CO2 cycle. We talked specifically how this could make up for extreme cases like snowball Earths and hothouse Earths. I pointed out that all through these phases of the Earth, life could have (and has) survived: life is very hearty and adaptable!

Finally, I ended with the leading theory of the formation of the Moon: A Giant Impact.

Notice the lack of interaction. This upsets me. I tend to do this unconsciously when I think I’m weak on a subject. I end up spending so much time learning the subject-matter than focusing on learning opportunities. This is a mistake, because it means the class won’t be nearly as interesting.

Next week will be Biology – another area that is NOT my specialty (the last biology course I took was in grade 10…more than 20 years ago). But, this time, I purposely put slides to generate discussion and review. I hope that will help keep things a bit more lively, and I will also be doing a review for the midterm.


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