Posts

Showing posts from February, 2012

Heat conduction, latitude and longitude

Image
In spring 2011 I ran a one off experiment on heat capacity. The lab was complicated by a lack of different materials with the same mass.  Thus materials that were tested varied in mass and composition. I returned to thermal conductivity in the fall of 2011 for laboratory 62 and stayed with thermal conductivity for spring 2012. The class had viewed a cartoon video on temperature and heat on Monday, followed by coverage of temperature scales on Wednesday.

Joyceleen and Lotrynes track temperature changes
Fall 2011 I opted to run a demonstration using the rebar and I tracked the temperature every two minutes. This modeling, not entirely intentional, led to the class generating two column time and temperature charts. This in turn led to xy scattergraph approaches and less diversity in chart choices during the group presentations.

Emerson and Roxanne watch for the peak temperature
In retrospect I did not like what had happened, the modeling had overly channeled the students down one path. Spr…

MS 150 statistics midterm assessment

Image
Eighty students took the spring 2012 midterm examination. Scores ranged from a low of nine to a high score of 34. The mode was 21, the median 23, and the average was 22.44. This represents a 66% success rate.

Performance was lower in the eight o'clock class with an average of 16.96. A histogram of the student score distribution makes clear the difference in the two sections. The eight o'clock section has been under performing the 9:00 and 10:00 sections due to a higher rate of absences and late arrivals to class.


The blue columns represent 8:00 student scores, the pink represent 9:00 and 10:00 scores. Note that the highest score attained at 8:00 was 25, well below the 34 attained by three students in the other two sections. There were 35 possible points on the midterm examination.

The low score in the 8:00 section was nine, no student at 9:00 or 10:00 scored below 13.


An item analysis was done on the midterm with the results shown above. Student performance was strongest on ba…

F.lux and the circadian rhythm

Apparently blue light is important to entraining circadian rhythm, potentially even resetting the rhythm or altering the onset of sleepiness by effects on melatonin levels. At the core of this clocking and melatonin cycle is the color temperature of light. Light color temperature may even directly impact slow wave sleep. Thus those of us who linger late into the night in front of the cyclopean computer eye may be able to push deeper into the night because the color temperature of the computer screen itself is helping keep us awake.

Enter F.lux, an applet that changes the color temperature of your monitor based on the time of day. I should note that the GUI for Ubuntu Linux did not function on my Lubuntu 11.10 rig, the computer very quickly reset the color temperature.

I did find, however, after installing the program using the lines:

sudo add-apt-repository ppa:kilian/f.lux sudo apt-get update sudo apt-get install fluxgui
I was able to successfully run the program from the command lin…

Mosses, lycophytes, and monilophytes

Image
For the past five or more years the term has started on a Thursday, which meant that the first ethnobotany class was also on the first day of class at the end of the week. Attendance had suffered as a result. This was the second term that class started on a Monday, which put the first ethnobotany class on the second day of classes on a full week of class.

On the first day I told the students that on Thursday they ought not bring books nor backpacks, and if they had such, they could leave them in the division storage closet.

On the second day of class, the class headed out on the hike into the valley of the monilophytes. I did not open the classroom, opting to leave from in front of the classroom at 3:30 to maximize the time available for the hike.

We stopped to put backpacks in the division supply closet. Behind the gym the class paused briefly as I looked for moss sporophytes. I did not see any and moved on.

This term I did not head down into the valley with the Psilotum nudum as a r…

Attendance in MS 150: First fifteen days

Image
Casual hallway talk early this term in the division has been about attendance or the lack thereof. I analyzed attendance in the first fourteen days of MS 150 statistics, tossing out day one as it was statistically aberrant with an unusually high number of absences. The course has an enrollment of 85 students in three sections. During the fourteen days analyzed there was an average of 11.2 absences per day across all three sections. On average 9.3 students arrive late per day, again, across all three sections. On-time attendance is achieved by an average of 64.5 students per day.

When asked, students most often cite transportation difficulties - late taxis, late rides. Some students also report having slept too late.

The chart below includes the first day of class and thus spans 15 days. Day one thirty students were absent and five were late. Day one attendance is typically weak. Faculty usually cite the add/drop period as ha…

Explorations of momentum, Hooke's law

Image
Laboratory four began as I have done so in the past, with an introduction to the behavior of marbles on a ruler. I usually lead off with the students gathered around observing a simple marble momentum conservation system.
Perihsa times
Five to seven marbles sit touching each other on the flat portion of a marble track. The marble track is made of two plastic rulers with grooves to guide the marbles. One to four marbles are released from an elevated end of the track. I demonstrated that "marbles in" appear to equal "marbles out." I noted that this also means that "mass in" must roughly be "mass out."

Seylyn Johnston on the stopwatch
I also qualitatively demonstrated that "speed in" appeared to be related to "speed out." This was all  done qualitatively, not quantitatively.

Lizmay working calculations
Jessica, Hanna, and Palikkun crunch some numbers
This term I deployed an electronic mass scale to simplify massing the marbles. In a…