Precambrian Time

I have here what some imagine to be a sprawling Precambrian landscape. My lessons this year on the precambrian were influenced by Lynn Margulis's lecture on geomicrobiology and symbiogenesis at Woods Hole this summer. Make no mistake, a lot of stuff happened in the first several billion years of earth's history. Birdley books 8 and 9 will have comics on this. In our class we talked a good deal about all the wild events that occurred during this time, as well as how our friends the cyanobacteria set up earth's atmosphere to support the diversity of life we see today by filling it with oxygen. Thanks to them our atmosphere is around 20% oxygen, enough to support the diversity of life we see today. What some people don't know was that at the time of the "Oxygen Revolution," the influx of oxygen into the atmosphere killed off a lot of the obligate anaerobes - microbial species that required oxygen-free environments. Some fortunate ones survived by finding oxygen-free habitats like thermal vents. Another thing I learned is that before the cyanos filled the atmosphere with oxygen they sent all the oxygen into the oceans. It reacted with dissolved iron in the sea to form rust, which became locked up in geological features called banded iron formations (BIFs). So you can see how microbes were starting to shape the earth and its geological features. I say if you have a chance to teach about the Precambrian, spend some time on it. A lot of stuff happened over those several billion years.

M&Ms

It is Friday again, and what a great week it has been. A busy week, as you can tell by the eclectic title. Much has been accomplished both with classes and with Birdley book 9. Hang in there, earth science teachers, a couple Birdley Earth books should be coming soon. I've heard a few requests for the new link to the Birdley site and the link to the home page is the same as before: http://www.birdleymedia.com/. The other pages are different, though, so you may need to re-bookmark any that you have bookmarked. Especially useful to educators should be the "Elsewhere" section, which has a lot of cool links on microbiology, marine biology, astronomy, and other sciences. The "microbial soup" blog also has a few meditations on microbes that might serve as fun facts for a class with some bio in it.
Back in the classroom, the main thing in physical science this week has been teaching my students the scientific method by completing a week-long lab activity with them on M&Ms. Sure we peppered it with a quiz there and a comic there, but M&Ms were the main thing. Students in a group of 2 or 3 opened a bag of M&Ms in groups and sorted them by color. Upon quantifying the M&Ms, they made a bar graph illustrating the number of M&Ms for each color. On the second day they then converted them to percentages to construct a pie graph... and finally on the third day we averaged all the group data to achieve a class data set.
Today we checked back to see that we had all of our data and then set about to create comics on the scientific method. Many great characters were created, such as the Evil Pie Chart, the Mad Mouse, and Bahama Llama. The kids had to illustrate a science experiment while outlining the steps of the scientific method. To model the work, I improvised one of these comics on the spot using the overhead. Taking their ideas and putting them up there was a highlight for me - I underestimated the amount of fun you can have with an overhead. To guide their work they also had a rubric which called for the required elements:
-steps of the scientific method
-2-3 pieces of lab eqipment
-one data chart
-clear pictures and explanations.
We used a basic six panel template that I did up in Microsoft Word. I emphasize that you don't have to consider yourself an artist - clear stick figures are cool as well. If you try something like this, let me know how it works out for you.