Monday, January 4, 2010

Adventures in the Lithosphere


lith⋅o⋅sphere
[lith-uh-sfeer]
1. the solid portion of the earth (distinguished from atmospherehydrosphere).
2. the crust and upper mantle of the earth.

The main science topic we have been covering this school year is earth science, which by definition is pretty broad but, for us it least, mainly constitutes the study of astronomy, geology, meteorology, and certain terms of geography.

Today, at random, on a walk to the post office we had a fun little exploration in geology (the study of rocks) and of the pedosphere (the layer of the earth in which soil formation occurs).

It started when, as we were waiting for the post office to open, we were noticing gravel on the side of the road, and started talking about erosion - how rocks break down to smaller and smaller pieces, from the big rocks we saw over in the landscaping to the tiny rocks on the side of the road. We had talked about erosion before, but this was a really good example, especially because of noting the cause of this type of erosion (in this case, mainly the cars breaking it up) and also the size variety was great, highlighting the bigger-to-smaller process. We also learned some new words - asphalt, concrete, and cement - a few words I noticed he didn't know when one of the clues on a birthday party treasure hunt this weekend was "concrete" and he looked at me with a blank stare.

As we continued our walk, another part of the roadside contained an excellent sample of mud, with lots of visible leaves, grass, and rock fragments. Which lead us to talking about what soil is made out of, the little organisms that help decompose organic material such as leaves and grass, and the different kinds of soil.

He, of course, wanted to make a footprint in the mud, which you can see in this picture. He sort of regretted it afterwords because the mud was a little deeper than it appeared.

As we cut across an open field to get to a park, we noticed the many cracks in the dirt, and talked about how the dirt made cracks like that because it dried up, and all the water had gone into the air (picture at top). I reminded him that it was called evaporation, and he said, "Yeah, like on the Magic School Bus!" (a video that my mom has. The dry parts, I said, is the place where water used to be, but now that some of the water is gone there is empty space there. We have been talking a lot about how water is in just about everything, and most things are mainly water (our bodies, food, etc.) even if it doesn't appear to be "wet", so it was fun to see another example of this.

The last thing on our little geology adventure was collecting a few rocks on the way, which were mostly remnants of landscaping rocks that had made their way across the street. I usually don't let him do that, and we talk about the whole concept of this is what would happen if everybody did, but for this time only (and since the base is somewhat deprived of very many nature experiences) we collected a few and are going to add them to our geology collection. (I know, it's bad)

It was a fun walk. I just love it when little homeschool experiences just "come up" like this. Even though it is really happening all the time and this is how a huge proportion of our "school" gets done, this day just happened to be an especially learning-filled little adventure.




"He cutteth out rivers among the rocks; and his eye seeth every precious thing." 
Job 28:10


Hunter is 4 years, 9 months old

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