Waves and the speed of sound

Week nine of physical science began with the laying down of a RipStik sine wave on three sheets of paper. About three wavelengths were laid down in 1.29 seconds with an 8 cm amplitude. Wavelength was measured at 57 cm. At 8 cm, the amplitude was a tad larger than in past terms.


I opted to shift the paper slightly east of where I usually locate the paper. Rain splatter was only one factor. The location worked well, I used a westbound run to lay down the wave.


The sheets were taped together, but not taped to the sidewalk


I then began to lay out the parts of the wave, explain definitions


By the end of the period the paper was fairly crowded. This term I used Desmos as a homework assignment. By having the students set up Desmos with variables, the automatic animation capability could be used to help the students comprehend amplitude and wavelength.



Thursday the class timed the interval between seeing two boards clapped and hearing the sound from distances of 200 meters out to 550 meters.

Maxon with the wheel and towel

Twain, Tricia, Francina timing

Maxon calls for another clap

The distances are large, yet the human eye can easily see the clapper

Should be Kenoma and Trisden down there, imaged from 300 or so meters. Marisha was the cell phone contact.

In the morning the class adjourned to the front of the library, but the Chromebook could not connect reliably from that location. The signal bounced around from below 40% to as high as 58% at one point.

Madlina at 11:00 with the wheel

Fog on the ridgeline, extreme distance viewing again

That should be Glenn, Anster, and perhaps Yuta. Yuta was the cell phone contact.

Diane, Madlina, Vandecia, Beverly-Ann, Josey timing out around 450 meters

Michelle Olter

Michelle was the flag bearer

Misko and Michelle


In the afternoon the class adjourned to the New Zealand room of the library where there is a strong WiFi signal. This allowed me to run tests for normality using the Statistics add-on for Google Sheets.

The lack of places to do impromptu group class work is a felt deficiency for a session such as today. We just needed a table somewhere we could talk without disrupting. The college has no such place at present. The library is all quiet work areas. The former group study room is now a center for entrepreneurship. I realize that the center can be used, but the center is primarily intended for the work of the center, not for use as a last minute "let's go there, share data, talk it out" location. The new student center might provide new options for the campus in this regard.

Comments

Post a Comment

Popular posts from this blog

Plotting polar coordinates in Desmos and a vector addition demonstrator

Image
In an earlier post I noted that Desmos did not directly plot polar coordinates. Not only was I incorrect, but Desmos responded to my blog to correct me! Although I had at some point seen that one could define a function f(x)=3x+5 and then have Desmos calculate f(6), I had not absorbed how this might be used to plot polar coordinates. The above works beautifully . Realizing that I could effectively program Desmos, I applied this thinking to demonstrating how to add two vectors when given the magnitudes m and the direction angles theta. The graph calculates the i and j components for the two vectors and then adds the vectors, graphically displaying the result while also providing information on the magnitude and direction of the vector sum. m1 and theta1 are the magnitude and direction angle for one of the two vectors, m2 and theta2 are the magnitude and direction for the other vector. All four are dynamically interactive and can be changed. The diagram purports to illustra...
Read more

Setting up a boxplot chart in Google Sheets with multiple boxplots on a single chart

Image
The  Google Statistics  add-on for Google Sheets can display multiple boxplots in a single chart. The key is the layout of the data. One column should be the variable by which the data is to be grouped, the other column should be the data to be box plotted. Set up the Statistics add-on with the data to be plotted as the variable, and the grouping column as the "by" variable. In this image I had deselected all but the boxplot option, the result was the appearance of the Moment, Standard errors, and Confidence intervals options. The default is apparently a 95% confidence interval for the mean. The result is multiple boxplots on a single chart with a common scale. The new tab that is created also quotes 95% confidence intervals for the mean. Note that as of 2018 the Google Statistics add-on cannot be found by search in the add-ons. In addition, as of May 2018 the add-on no longer verifies, possibly due to the add-on not having been updated since August 2017. One may ha...
Read more

Traditional food dishes of Micronesia

Image
Clara, Jennette, and Joanie presented ground hard taro cooked in an umw, effectively a hot rock oven. Pohnpeian: rotama. Pingelapese: sero. Mwoakillese: rodma. Mortlockese: Amahd. Kosrae: rodoma. After cooking in an umw the rotama is pounded with the petiole of a palm frond. Rotama is made from hard or swamp taro, known as mwahng on Pohnpei, mweian on Pingalap, pula in Mortlockese, and pahsruhk on Kosrae. In traditional times on the outer islands the women had primary responsibility for tending the taro while the men handled fishing and climbing tasks. Joesen and Noeleen presented fermented breadfruit from the outer islands of Yap such as Woleai and Eauripik. The raw ingredients were actually brought in from Yap, Noeleen prepared the maare.  The leaf wrap is ti leaf - Cordyline fruticosa. Pauleen, Barnson, Trisha, Verginia, Con-ray, and Maylanda from Kitti, Pohnpei brought in mahi umw, koahpnoair koakihr, and uht sukusuk. Above is breadfruit umw, mahi umw, o...
Read more