Mar 3 2010, Takilma OR

by Daniel Dalegowski

Topics today:
  • PH testing with Joe
  • Carbon cycle diagram with Lori
  • Gasifier construction with Kelpie

PH Testing with Joe


Joe used PH strips to test both vinegar and ammonia to establish the extreme parameters of acidity and baseness, respectively. These two readings were places at opposite ends of a piece of paper which the students then filled in with the results of testing other substances. First they discussed which substances could be mixed and speculated on their acidity. Bases are slippery, acids smell bad. Some foods are bases, some are acids. It was noted that bases are often used for cleaning.

After testing several different common substances the students tested lime water, like the lime water which they made in a previous activity. The PH test of the lime water allowed the students to conclude that CO2 has an acidic quality. Joe explained the phenomenon of acid rain, and it's relationship to CO2. The relation to the Oregon Caves was also discussed: since acidic rain water enters the limestone and reacts to form the caves, the water leaving the caves must be neutral.

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PH testing

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Distributing the PH testing strips

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Labeling the items on the PH spectrum

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Joe entertains and explains

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The PH spectrum

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Some of the items tested



Carbon Cycle Diagram with Lori


The students created their own charts of the carbon cycle. These graphic representations contain elements familiar to the students: bird feces is a popular character in the drama. The carbon cycle charts are works of art in their own right and several are included here.

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Lori and students diagramming the carbon cycle

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Carbon cycle diagram

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Carbon cycle diagram



Gasifier Construction with Kelpie


Kelpie led the students in construction top-lift wood gassifiers. These were made out of two aluminum cans; one smaller than the other and inserted inside. The inner can is perforated with a nail and the outer is cut into a manifold to allow the proper flow of gases. The project involved measuring, marking, cutting, and bending. The students were very adept at aluminum construction and it was a good exercise in safety. There were no major injuries though the risk was high with the many sharp edges involved. The students did very well at working with sharp metal, pliers, wire, and tin-snips.

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Wire for the gasifier lid.

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Gasifier lid construction.

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Group folding strips for gasifier lids.

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Early construction.

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Kelpie assisting.

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Group shot, Kelpie demonstrating attaching the inner can.

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Kelpie doing the difficult cuts with tin-snips.

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Measuring and marking for cutting.

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Tin snipping; very difficult.

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Twisting every other strip to construct the lid.

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Nearing completion.

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Threading the wire handle into the lid.

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Close up of folding strips for gasifier lid.

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Finished gasifier.

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Final touches on lid.

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Large and small gasifiers in action.

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Small gasifier working away.