Hoop rotation exploration

This summer term the hoop rotation laboratory was made less specific, less prescriptive of what had to be measured. In the past the laboratory was guided by the following directions and questions:

In this laboratory you explored the relationship between a hula hoop diameter in centimeters and the natural rotation period for the hula hoop in seconds. 

  1. What is the nature of the mathematical relationship between the hoop diameter and hoop period? Is the relationship linear or nonlinear?
  2. What is the equation that relates hoop diameter to the hoop period?
  3. Do hoops with larger diameters have longer periods?

This summer the intent was to leave the decisions on what to measure to the students. The concept was to make the laboratory more of a practical test of the students' ability to explore an unknown system. To remove some of the scaffolding and framework. This summer the directions were:

If the universe is mathematical, then every physical system is obeying mathematical equations.
Hoops are a physical system. Hoops come in different sizes. How do different size hoops behave when rotated around the waist?
Pair up with a partner, groups of two. One timer, one hooper. Make certain either you or your partner can hoop.
Design and carry out an experiment to determine whether there is a mathematical relationship between the rotation rate around the waist and the size of a hula hoop. In your report explain what you decided to measure and why. Find an equation that optimally fits your data. Remember to specify your variables and units of measurement in your caption and graph axes. In the discussion report your results and findings.
This laboratory is a practical test of your ability to carry out a study of a physical system and produce a report on that system without guidance.

Harston hoops while Franson times

During the unguided laboratory the students usually chose to measure the circumference. Given a dual sided cloth tape measure, they primarily chose to measure the circumference of the hoop. The students also appeared to try to either measure a single rotation of the hoop or a fixed number of rotations. The latter would prove difficult if the number of rotations was set on larger hoops. Shorter hoops would prove harder to keep aloft for the pre-determined number of rotations. Notes on time suggested that some students were recording times in minutes and seconds. 

Trinidad opted to measure the circumference 

Perhaps the direction to go is away from this as a lab practical and back to specifying period versus diameter. Or five rotation time versus diameter to keep the math and timing simple. Paired partners. Then write the equations on the board. Did everyone get the same equation? Why not? What factors might account for the different results? Watching one student slow rotate a small hoop on almost no body motion this summer made clear that while the general relationship holds, there are clearly other factors.

Austin hooping

Trinindad discusses timing data with Elain

Austin with the large hoop

Comments

Post a Comment

Popular posts from this blog

Experimenting with the PlantNet and iNaturalist apps

Image
The application of image recognition technologies as the back end to botany apps is providing increasingly relevant search results. Over the recent winter break I began looking at whether the apps now available might be useful to the ethnobotany class here on Pohnpei. Some apps had a more regional focus in the past and were better at north american or european plants. Pohnpei has a both unique indigenous plants and many introduced plants from around the world -  a challenging environment for any image recognition system. A student working with a plant identification app for the first time My criterion was that the app had to be appropriate for use in my classroom. The app could not contain advertising and the app had to be free, my students typically do not have the ability to pay for an app. The app would also have to be fairly small as my students often use phones with limited memory and processing power. I settled on PlantNet and was impressed with the ability of the a...
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