### Thermal expansion, Binky, Meters per Minute of Longitude

Tuesday was an experimental lab investigating the thermal expansion of a steel pipe. This was a revisit to a laboratory from spring 2000. I wanted to rerun the lab to see whether there was a useful mathematical relationship to be exploited, something I had not looked at back in 2000.

The rig was straightforward but far from perfect.

I had only a steel pipe, which has, relatively speaking, a small coefficient of expansion. I realize that work done in 2000 suggested a PVC pipe has the largest thermal expansion. I also know that insulating the pipe is useful, as is clamping the pipe and sealing the steam input end. My goal, however, was to get a rough look at the mathematical model.

Data on the board.

Results. The expansion was linear up until the pipe heated along two-thirds of the length of the pipe. Radiant and convective cooling prevented heating beyond the two-thirds mark - up around 200 cm. Once that 200 cm was hot, the pipe heated no further and expanded no further.

Binky was from Senny's this summer.

Binky tied to a tree in a shallow valley out beyond the southwest side of the campus.

Binky's location at 6:20 A.M. The grass is wet at that time.

The view from Binky's spot.

Ursula on the hunt for Binky.

Pamela and Charlotte with GPS and location data.

Charlotte studies the instructions.

Charles closing in on Binky.

Charles finds Binky! Time to find at around thirty-five minutes.

Emmy Rose and Maria-Asuncion slog uphill in tall grass. They were the closest to Binky at one point, but their local knowledge worked against them. They knew about a back trail - actually the trail I used to plant Binky. They left the area above to circle around onto the back trail. Charles did not know about the back trail and ploughed forward following only the numbers on the GPS. He took the most direct path.

I shouted out "Binky's found!" and thirteen of the fifteen regrouped up at at the gym. As we headed back I realized we had lost Emmy Rose and Maria-Asuncion. I knew they were from the area and would know the lay of the land, but there are some surprises farther down the slope, including a grass-covered Japanese era slot trench.

I headed back to the area of Binky and saw Emmy Rose and Maria-Asuncion out near where Binky had been. I had not realized that they had circled around, and they were out of earshot when Binky was found. They did arrive at the right place, but had no idea Binky had already been rescued. Local knowledge worked against them today.

In the afternoon, starting at the "second palm" at  N 06° 54.570' and E 158° 09.600' makes the calculations in the field much easier than a 0.598' or 0.599' start.

Looking back upon the "second palm."

I opted to roll off hundred foot segments, calling them 30 meters. The error is small. While the error could be reduced by using 99 foot segments, 100 is, again, easier in the field.

Data tracking with GPS units.

Data being recorded.

Pamela checks her GPS readings, Heron on the right also watches his GPS.

The thermal expansion did not go as well as hoped and is not in the form as done a path forward for lab six. Binky was hidden farther out than in the past, and the constant latitude path came close to the pocket cliff at the back of the new ethnobotanical garden. The road, however, kept all groups north of the true latitude line, and no one was anywhere near the pocket cliff. Binky went well, as did the afternoon lab.