Heat conductivity of materials

The two styrofoam cups are connected by a material to be tested for heat conductivity. The lab included aluminum rods, iron rebar, a wood stick, brass rods, copper cylinders, steel bolts, a length of lead pounded from a fishing line weight, a hunk of basalt, and any other materials we could access. Boiling water goes in the one cup, the other cup is filled with just enough room temperature tap water to cover the material in the bottom. Lynn and Marsela watch for the maximum temperature rise of the tap water.


The hot water melts the glue, so a glue gun is used to repair the styrofoam cups on the fly. This is faster and safer than solvent based glues. Annnie and Clyde work on repairing their cups.



In the 8:00 section I was unable to get a class discussion going. Getting a true class discussion going can be challenging, especially when the topic is terra nova for the students. Asking the students to come up with a chart or graph to use to communicate their results has the students working with science and with charts and graphs. Both areas are unfamiliar.


At 11:00 I knew I had too large a group to get a discussion going, so I simply combined laboratory partner pairs into discussion groups of four to six. I gave each group 15 minutes to come up with some idea of how to present the data. One group was unable to put together any coherent idea, but the other four groups presented a variety of ideas. Three groups utilized variation on a column chart, the fourth group hit upon using an xy scattergraph.

Of interest to me was that no one in either class hit upon the idea of using the change in temperature as the graphed variable. No class over the past three years has thought to use the change in temperature to deal with the conductors having different starting temperatures. The use of delta T is not obvious to the novice. This implies that the concept is more cognitively complex than one might expect.

Those who work in physically sciences might move to the change in temperature almost intuitively, sensing that the change is what we really want to display. Even in the classroom I have to tie my tongue to resist blurting out, "Why not look at the change in temperature from start to maximum?" The key to this discussion however is "no teacher talk time." The students have to wrestle this one down to the ground themselves.

At the very end of class I do wrap up by noting that what they just engaged in, a community discussing results, what those results mean, and how to present those results, are important parts of science.

Alisi presents the ideas of group one.

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

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

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