072 Meters per arcminute

Despite this being an El Niño season, heavy rain fell from the early morning hours of Thursday. 

After covering the hide and seek results from yesterday, I set up to run the laboratory as was done in fall 2022 using the covered walkway between administration and the dining hall. 

I then laid out the three goals of the laboratory. 

Wind driven rain swept across the campus during the laboratory.

The measuring wheel was used to measure off 30 foot lengths, a spreadsheet handled conversions. 

30 feet was 9.14 meters. Note that this term I did not use the handheld GPS units, relying instead on students downloading and using GPS Essentials on their Android phones. iPhone users were advised to team up with an Android user for data. Apple Compass only displays in D°M'S" format. 

The 8:00 section returned to the classroom to wrap up the laboratory.

The 8:00 section worked with values based on the lab of fall 2022. 

At 11:00 I shifted to 33 foot intervals. This rationalized the distances on the y-axis. Distances of 33, 66, 99, 132, and 164 feet were used. Note that 164 feet is only 32 feet beyond 132. By this point the rounding error has reached one foot. I was also able to report the starting longitude at 11:00 and illustrate the mathematical operations to return (0 arcminutes, 0 meters) to the dataset. I also now knew that ten meter intervals were possible. 

Daniel using GPS Essentials to obtain longitude data.

Louisa Carmina records data. 

At 11:00 the class worked at whole decameters, except for the last measurement. 

The short distance, rounding errors, and perhaps the overhead roof lead to more variable conversion factors. Students were getting slopes from 1700 to 1900. The actual value is roughly 1846 meters per arcminute at seven degrees north as I recall. That said, this variant works well enough on rainy days.