With the help of Scott Woodbury from the Shaw Nature Reserve, Dr. Sansone lead the effort to remove the six mature Bradford Pear trees from the front of the school over the last interim. We collected slices of each of the trees so students could do a little dendrological work with the tree rings.
The trees were planted as part of the original landscaping of the school campus. They’re pretty in the spring and fall, but are an aggressive invasive species.
The fast growth, however, make for wide growth rings. In fact, in addition to the annual rings, there are several millimeter wide sub rings that are probably related to specific weather events within the year. I’d like to see if we can co-relate some of the sub-ring data to the longer term instrumental record of the area.
The tree cutting was quite fun as well, despite being done on a cold day near the end of November. Students helped stack logs and organize branches along the road for the woodchipper. I learned how to use a chainsaw.
Six Bradford Pear tree slices, cut on November 25th, 2013.
We’ve looked at the simple acid/base reactions that produce the carbon dioxide bubbles in chocolate-chip cookies, but this video goes over a number of other relevant chemical concepts and the temperatures at which changes occur, including:
Emulsions: butter is an emulsion that separates into its constituent fats and water at 92ºF,
Ms. Hahn shared this with me because, “This video — in all of its girl awesomeness — reminded me of your recent Rube Goldberg blog entry and my visit to your classroom to see your middle school students’ “machines.” Entertaining.”
One of my students asked me, “Can we spend next week working on our machine?” And I said yes.
Students choose to spend their time building a complex, Rube Goldberg machine with pulleys, inclined planes, motors, and microcontrollers.
This was a week and a half ago. I’d planned on to starting the discussion of conservation of energy as we transition from mechanical to thermal and electrical energy. However, I find it hard to resist when students ask to pursue an area of work. Students learn a lot more when they’re intrinsically motivated.
So, after the request to continue working on the machines I did an informal survey to see if the rest of the class were interested. They were quite interested, and the vast majority really wanted to continue on their projects — or something similar — rather than just having an opportunity to slack off.
I, therefore, let them have the time. My only requirement was that they state an objective for the week.
One group’s goal was to build a complex machine with 500x mechanical advantage. Another student — I let them choose their own groups or work alone — simply wanted to build a working pulley system; something he been having trouble with all month. A couple of other groups wanted to build robot projects.
And they went at it. All week long students would come into class eager to work. On Wednesday I got back into the science room a few minutes late for class, and they were all in there working away. It is a wonderful thing to be able to walk into a classroom with the whole class on-task and combining their new knowledge with their creativity.
Of course, after the first few days the projects evolved. I gave one group a Lego microcontroller and a quick lesson to help them activate the second part of their pulley system.
Another group quickly finished their robot and wanted some sort of track that it could follow. I did not have a track, but digging around in the store-room uncovered our track building kit — one of the ones with loops and jumps that’s great for learning about inertia, and conservation of energy. I also helped them out by giving them a fire pit (with green flames) for their marble to jump.
In retrospect, I realize that I should also have had them keep a daily diary of their work — I had to settle for summary at the end of the week instead — but they did some really exciting, self-directed work that I was really proud to see.
The amino acid methionine, aka 2-amino-4-(methylthio)butanoic acid.
During the last interim, we paid a visit to Novus International, a large, multinational, animal nutrition company. And now that we’re talking about proteins in biology, there’s some extra relevance because students are aware of Novus’ major products that are precursors to the amino acid, methionine (they sell about a billion dollars a year).
Solid and liquid forms of the methionine precursor MHA.
I particularly liked the set of speakers they chose for us, because they covered such a broad span of the company: from business, to marketing, all the way through to the science. They also gave us a tour of their highly energy efficient building, and grounds that they’re landscaping with native plants and vegetable gardens.
It was definitely a worthwhile trip. Thanks to Ms. Mertz for arranging it.
