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Showing posts from June, 2014

Humidity, Clouds, Sound Speed Data

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Monday the class watched Planet Earth disc two climate change.


Tuesday I started by going over the test from Friday and then covering relative humidity.


Tuesday afternoon I began with coverage of clouds in the classroom. Then I took advantage of an empty A204 to show a cloud slideshow in Google Plus. The complication was that the bandwidth is simply not available to show a Google Plus slide show in the lab. By midday the campus network is simply too saturated to support an on line slide show.


I mentioned only in passing the Bergeron process. That afternoon around five a large cell would develop on the west side of the island. A fisherman from Tamoroleng in Kitti would be killed in a lightning strike on his boat - an exceptionally unusual event here. Despite Pohnpei being in the tropics, the island rarely has thunderstorms.


Wednesday I rode a RipStik on paper, choosing to echo the wave on the board rather than work in the field.

The centerline of my RipStik run was not straight. I did …

Measuring pi and making waves with a RipStik in Algebra and Trigonometry

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Sunny weather permitted going outside to measure pi in MS 101 Algebra and Trigonometry.

Angie Joab remained at zero degrees, Jamal Ranganbay held the line taught, Maybelline Ihara rolled the measuring wheel.

Tommy Wichilbuch Jr. anchored the center of the circle.


Jamal heads counter-clockwise passing through pi over four radian, Maybelline trailing along.

Shra Ringlen was at 180° or pi radians.


Jamal passing through 270°. Maybelline would eventually measure 268 feet around the circle. From Angie to Shra, the diameter, was 87 feet. The resulting pi was 3.08. Maybe I should have started with something small, like wrapping paper around a pen, moved up to a coffee can, they the surveyor's wheel, and then moved out onto the lawn. Show that pi is invariant with circle size.


Section 6.3 sine wave lay down. This time I prefaced by graphing y = sin x using WolframAlpha in class. I also started from a stop, accelerating on the paper.


This led to a less stable center line, but the changing w…

Thermal expansion, Binky, Meters per Minute of Longitude

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Tuesday was an experimental lab investigating the thermal expansion of a steel pipe. This was a revisit to a laboratory from spring 2000. I wanted to rerun the lab to see whether there was a useful mathematical relationship to be exploited, something I had not looked at back in 2000.

The rig was straightforward but far from perfect.


I had only a steel pipe, which has, relatively speaking, a small coefficient of expansion. I realize that work done in 2000 suggested a PVC pipe has the largest thermal expansion. I also know that insulating the pipe is useful, as is clamping the pipe and sealing the steam input end. My goal, however, was to get a rough look at the mathematical model.

Data on the board.


Results. The expansion was linear up until the pipe heated along two-thirds of the length of the pipe. Radiant and convective cooling prevented heating beyond the two-thirds mark - up around 200 cm. Once that 200 cm was hot, the pipe heated no further and expanded no further.


Binky was from…

Acceleration, momentum, and pulleys

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Monday class was held in MITC. The class watched the first three-quarters or so of Earth from Space. Tuesday began with a review of the linear motion of rolling balls at different velocities, laboratory two results.
Then I moved on to note what a decelerating or accelerating ball would look like on a time versus distance graph.

I also covered a velocity of zero and returning back to a starting point - negative velocity. This was in preparation for the RipStik deceleration run on the sidewalk.


The RipStik deceleration run went surprisingly well. I did a single practice run. For the timed run I started with the same post which had been zero for laboratory two, heading west towards the LRC. I used the posts, which I found to be 305 cm center on center including the sidewalk spanning post set that I had thought was a 320 cm span. That span is apparently 305 as well.

The data went well. I did a hand calculation of a fit, and then ran a calculation on a calculator. Laboratory three, in the …