Flying disks and mathematical models

The morning of laboratory fourteen dawned overcast and threatening rain. As a result I opted to run with a zero introduction, data collection first, start to the laboratory. The laboratory launched with two students on a cloudy and cool Thursday morning. A third would join as I set up the tape measure one the lawn.

A morning ridge cap pileus form cloud under overcast skies

Equipment this term

I opted to use only the Frisbee™ Golf discs as they proved uniquely capable of straight line, flat flight during first use spring 2019.

Darall would take up throwing the Frisbee

Eric reported distances and returned the thrown Frisbee

Mauriney recorded data

Speed versus distance data

The zero launch led to no preliminary discussion of what the system should or should not do, and no expectation that a zero speed should lead to zero distance. Note too that this term I opted not to provide converted meters per second values, to just run with the raw kilometers per hour. The slope units have long puzzled me - meter per (meters per second) were the units of the slope each term until this term. But this suggested that the units of slope were time. Although potentially related to time aloft, the fact that one can throw a short "floater" and hard and fast line drive with similar times aloft argues against the slope being purely time aloft. Using meters per kph leaves the unit issue somewhat more ambiguous.

Linear regression on speed versus distance data

The data is rather well modeled by a linear regression, provided that the y-intercept is not fixed at zero. This result surprised me as data in prior terms has suggested that a y-intercept of zero was a reasonable data point.

To even be able to include a y-intercept of zero (zero speed logically entails zero distance) a non-linear function would be needed.

Quadratic regression

A quadratic regression fits the data well and allows for a y-intercept of zero. A quadratic regression cannot be ruled in or out based on the data.

In the 11:00 section, held after Thanksgiving lunch, one group obtained distinctly non-linear data.

Distinctly non-linear data

Susan, Staisy, and Kimmy on the throwing line in light rain at 11:00

The 11:00 section started at noon, after the Thanksgiving lunch, and worked under light rain. The throwing area became rather a mud pit unfortunately. The throwers worked barefoot to contend with the conditions.

RayJohnBurg, Jerick, Joyceleen, and Dexter on the measuring and retrieving side

Mayboleeen recording from the porch. Gregorlyn arrived late, even for a noon start, and sat out the laboratory