This week I did my second class for my 8-9 year olds on Geology. The topic this week was "Earth Structure" and "Plate Tectonics". My main resource this week was a video called "Greatest Discoveries with Bill Nye: Earth Science". What I love about this video (other that it's laid out in chapters for teachers) is that it explains how scientists have figured all of this stuff out, and all very recently too! For someone who feels that problem solving is probably one of the most important things we can teach our kids, this video stands out because it focuses on the how as much as the what. Admittedly, this is not the easiest video to get your hands on. I got it from A+ video, but you can also find snippets of it online here. It's aimed at 6-12 grade, but you may have figured out that I don't really follow "grade level material"!
In talking about the structure of the earth I did the obligatory clay model with them, putting a new color on their little Earths for each layer. We started with a marble, since the core of the earth is solid iron and nickel, and then layered yellow (outer core), orange (mantle), and blue and green Model Magic(crust) over that. This gives them a real hands-on feel for it all. In theory, you could cut a wedge away and see the layers inside, but in practice I only able to cut one for this picture after the Model Magic dried completely. The colors get all squished and mixed up if it's all still wet. Here is a nice plan for this exercise I found online, with a worksheet and everything, though I didn't actually use it all. An egg can also serve as a good analogy of the Earth, by the way. The shell is the crust (very thin), the white is the mantle, and the yolk is the outer and inner cores.
I explained how all that iron and nickel sets up the Earth's magnetic field and how this protects us from the worst of the Sun's solar wind. A few iron filings and a magnet served nicely to show the lines of force.
Here are some great online videos and sites to look at:
http://dusk.geo.orst.edu/oceans/PPT/PlateMotion.html this is a nice plate motion animation
http://www.amnh.org/ology/index.php?channel=earth#features/plates?TB_iframe=true&height=500&width=750 the Ology website from the American Museum of Natural History has some neat stuff, put this pertains specifically to plate tectonics, and if you go to the button titled "Explore How Plates Affect Your World" there is a nice tutorial and demonstration.
http://earthquake.usgs.gov/earthquakes/recenteqsus/ At the USGS website, you can view real-time info on earthquakes in the United States and around the world.
The American Museum of Natural History also had a nice activity that I had the kids do as our final activity. It's basically a puzzle of the continents. They have to put the continents back together to reconstruct Pangea using clues on the pieces, like similar pictures of fossils on each continent. The pdf. is here: http://www.amnh.org/education/resources/rfl/pdf/dinos_plate_tectonics.pdf.
The hardest part about this is that I had to personally cut out all the continents for them. I didn't want it to be a long exercise in cutting frustration, so I took all of that upon myself. Still I think it was worthwhile.
In the full length video category, "Inside Planet Earth" from the Discovery Channel isn't too bad.
Finally, here are some book resources. I didn't use all of these, but they are not too bad nevertheless.
The Magic School Bus: Inside the Earth (book) by Joanna Cole
Our Patchwork Planet by Helen Roney Sattler
Evan-Moor Geology Science Works for Kids Series Grades 1-3 (this was a little bit simplistic to my taste, but it did have some decent diagrams you can copy)