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Ohigan and ethnogardening

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With the sun crossing the equator on the 23rd of September, the ethnobotany class took to cleaning up the Haruki cemetery on campus. The following are images from the clean-up. 
Arlynn clears tall grass while Tulpe watches
Justin and Jerome did heavy grass whacking work along the front of the cemetery

Ixora casei on the far right, Cananga odorata in the background
More Ichaemum polystachyum cutting, Venister chipping in
Arlynn, the Cananga odorata on the back left. Hibiscus tiliaceus behind Arlynn


Adelma next to the Acacia auriculiformis, Alpinia carolinensis behind her in the background
In the center left, Coffea arabica. On that is growing Piper nigrum
Jerome strikes a pose - photographs were being taken by Bredalyn
On the left side of the image is Volkameria inermis, formerly Clerodendrum inerme

Almost everyone was engaged in the Ohigan clean-up



I was cutting Hibiscus tiliaceus that was blocking sight lines into the cemetery. Cananga odorata in the foreground. The cemetery becomes …

Friction

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After what was a failure to demonstrate that force is equal to a change in momentum, Wednesday was devoted to coverage of Newton's laws of motion and force from a RipStik. This is a lecture-demonstration done while riding a RipStik and holding a ball as seen in images captured last fall.

Thursday's laboratory turned attention to the issue of friction and what has the largest impact on the force of friction.

Rangpino and Dorothy working on whether surface area affects the force of friction
Stacey and Janice Stacia working on the effect of weight on the force of friction
Merenda and Maylina worked on how surface roughness affects the force of friction

The red line is the roughness data (using particle size in micrometers), the purple line is the weight data, and the blue line is the surface area data (in square centimeters) for three sets of data.


The set up on the board on Thursday.

On Friday each group presented their findings to the class.


The groups investigating weight gene…

Healing plants presentations

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Healing plants presentations in ethnobotany continue to evidence the deterioration in general knowledge coupled with what appears to be an overall lack of preparation. The banning of the presentation of Psidium guajava is likely necessary. Four students fell back on this plant, all with the same remedy. The tree grows outside the classroom.


Venister presented on the Kosraean use of the heated leaf of kiuf to treat groin swelling. I was unable to determine whether the leaf was Hymenocallis littoralis or Crinum asiaticum. Note that in Pohnpeian the two plants have the same local name, kiepw. There is always the possibility that either can be used in this treatment.


Via-Marie covered the Pohnpeian use of Psidium guajava for diarrhea, mehntang.


Justin described the Mwoakillese use of the skin of the lime fruit for constipation. A tea is made from the skin and consumed for four days.


Jerome shared the Pohnpeian use of Senna alata as an anti-fungal. Young leaves are crushed and rubbed into …

RipStik change in momentum is force

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Based on the providing a transition from coverage of momentum on Friday, I attempted to show that the external force would be equal to the change in momentum. The layout was similar to attempts to measure this from a few terms ago, but with some changes.


I began by repeating from Friday the relationship of kinetic energy to momentum. Then I added the caveat, "provided that no external forces act on the system."


I then introduced a Newtonian definition of force as the change in momentum with respect to time. I also outlined the procedure I hoped to follow. I noted that I intended to start from rest, an initial velocity of zero, which would have a momentum of zero. I hoped to increase my momentum over a three meter distance, then use a 1.5 meter distance to measure my final velocity. The final velocity would be used to calculate my final momentum. Two imers timed the time t₁ over the first three meters, during which my momentum increased. Three timers measured timed the 1.5 me…

An exploration of marble momentum without the word momentum

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As noted in an earlier blog, over the years I have gradually developed better transitions and connections between the aspects of motion in the physical science class. Linear motion often yields a slight amount of non-linear curvature. Week three specifically explores that curvature as acceleration. Week four began with addressing the misconception that previous laboratory had measured the speed of the ball when the ball hit the floor. Thus week four began with gathering data on height versus speed at the bottom of that height.

I chose to make a small, subtle, yet in retrospect a critical change in the way the laboratory during the fourth week was approached. I brought in marbles, more than previously. I brought along a mass scale, timers, scotch tape, and a plethora of rulers.


More so than in prior terms I emphasized the pedagogical nature of the laboratory up front. I noted the history of the course as being originally designed to serve both the general education science with laborat…