Today I Learned (TIL)

From pages 170 & 171:

[T]he multilateral treaties, conventions and agreements of an economic or technical character enumerated below … shall alone be applied as between Germany and those of the Allied and Associated Powers party thereto:

. . . .

(22) Convention of November 16 and 19, 1885, regarding the establishment of a concert pitch.

That way you get a draft to cool you off more in the summer and avoid such in the winter. I even noticed that switch before but never thought about what it might do...

To clear up confusion, IQ tests are standardized so that the mean is always 100, but if a person today take a test from 30 years ago he'll probably score poorly and if he takes a test from 80 years ago he'll score great.

No one knows why the trend started or stopped.

Roman hours were not of a fixed length because they simply equal to the amount of light or darkness on a given day divided by twelve. Since the amount of daylight varies greatly from day to day over the course of the year—with perhaps as many as 15 hours of daylight in the summer and only 8 or 9 in the winter—a Roman hour in the summer might be equivalent to a modern hour and a half, and, similarly, in the winter, a Roman hour might be only 40 of our minutes long.

As an alkaline battery is discharged, the anode undergoes oxidation from Zn to ZnO.

…

The battery most likely begins to bounce because of displacement of water by solid ZnO bridges between particles of zinc in the gel. These bridges provide less impeding and attenuating paths for pressure waves, in turn making the battery bouncier.

Bhadra, S.; Hertzberg, B. J.; Hsieh, A. G.; Croft, M.; Gallaway, J. W.; Van Tassell, B. J.; Chamoun, M.; Erdonmez, C.; Zhong, Z.; Sholkapper, T.; Steingart, D. A. The relationship between coefficient of restitution and state of charge of zinc alkaline primary LR6 batteries. J. Mater. Chem. A. 2015, 3, 9395–9400.

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Although almost everyone does it all the time, when trying to pantomime it without visual feedback, we essentially always forget to turn back to straight and just something like a 45° turn.