Waves
Monday was an observation day and thus I wanted to see if I could run the RipStik wave introduction in A101. In the morning I tested the RipStik on a sheet of poster pad in A101. No mark. The floor is too smooth.
The shiny looking wheels are because... that is a new board
But the sidewalk outside A101 left a strong track. So I used the sidewalk, which is rough enough to cause a difficult start. Then I brought the three sheet poster pad inside and put it up on the board which improved visibility.
I thought I had seen the timer record 1.71 seconds, but post hoc the timer was blank and was in countdown mode. At the point I realized that I did not have a reliable time I already knew I had 3.5 wavelengths on the paper. I ran with 2.1 seconds for the full transversal. This produced a period of 0.6 seconds and a frequency of 1.67 Hertz. The wavelength came in at 70 cm. The track was not straight but was close enough.
The wave speed worked out to be an estimated 119 cm/s, which was undoubtedly below the actual wave speed as the traversal was probably shorter than 2.1 seconds.
Wednesday covered waves on a rope and the introduction of sound waves via a bouncing golf ball and a meter stick.
A wave on a rope.
The rope wave was timed at 10 oscillations in 2.84 seconds with a wavelength 𝜆 of 195 cm and an amplitude of 20 cm. The other board calculations relate to a bouncing golf ball, which starts the transition to sound waves.
On Thursday this term I found only a coral stub to mark zero meters.
As is often the case, the morning section started off with light attendance. Ian handled clapping. Conditions were particularly challenging due to extreme humidity and direct sun. By 11:00 the humidity had dropped making conditions more tolerable along the road. With the sun behind Ian, reflections off of cars were particularly blinding and prevented the timers from seeing the clap if a car reflected light down the road.
There were students who showed up late but who opted to remain in the shade with Ian. This left the heavy lift to the early arrivals, so I granted a data gathering hardship of 20 points assigned only to those who were there to gather the data.
Wayne, Emleen
The 8:00 class then gathered at the picnic tables.
Renae and Pevirleen recover in the shade
The board at class start was minimalistic at best.
Aryolynn, Ruth, and Darian head west
The first stop at 244 meters would prove to be too close for accurate timing
In the field data is gathered into a spreadsheet. Data is entered using the Tripltek tablet in the field.
Ivy, Malachi, Darian, Aryolynn, and Ruth
A second tab handles automatic calculation of the median. This allows the group to take more data than could be coped with in the past and manual calculations. One distance would record 26 times, far more than would have been attempted when the course was working with paper and pencil.
Alyssa, Ivy, Leriangelica, Malachi
The second tab also handles the conversion from feet on the measuring wheel to meters automatically.
Out around 351 meters at the gym
438 meters at agriculture in a shady spot
Although warmer in temperature, the humidity has dropped by midday which makes the heat less oppressive.
The view back from 438 meters
Heading back to the dining hall pre-selected rendezvous location
The spuriously long times for 244 meters can be seen in the above graph: the time gap was too short for the students to accurately measure.
Deep dive into the data for both sections combined
Friday wrapped up with Cymatics.
Comments
Post a Comment