From Lee Sallows:
(Thanks, Lee!)
Science & Math
Amalgamation
Putting mercury in contact with an aluminum plate has some surprising consequences (2:05).
“A Whisky Puzzle”
In 1895 a London shopkeeper attracted customers with a glass cask of whiskey — they were puzzled to find that no matter how much liquid they drew off, the level in the cask never dropped. The container could be viewed from any angle, and it stood well away from the wall. How was this possible?
A hidden pipe connected the bottom of the cask to a tank in another room. When a customer drew a glass of whisky, a confederate there would open a tap to replenish tank B, and the liquid, seeking its own level, would maintain the same height in the cask.
(James Scott, “Shopkeepers’ Advertising Novelties,” Strand, November 1895. See Desert Downpour.)
Pandigital Products
From reader Hans Havermann: Each of these equations uses each of the digits 0-9 exactly once:
8596 = 2×14×307
8790 = 2×3×1465
9360 = 2×4×15×78
9380 = 2×5×14×67
9870 = 2×3×1645
10752 = 3×4×896
12780 = 4×5×639
14760 = 5×9×328
14820 = 5×39×76
15628 = 4×3907
15678 = 39×402
16038 = 27×594 (= 54×297)
16704 = 9×32×58
17082 = 3×5694
17820 = 36×495 (= 45×396)
17920 = 8×35×64
18720 = 4×5×936
19084 = 52×367
19240 = 8×37×65
20457 = 3×6819
20574 = 6×9×381
20754 = 3×6918
21658 = 7×3094
24056 = 8×31×97
24507 = 3×8169
25803 = 9×47×61
26180 = 4×7×935
26910 = 78×345
27504 = 3×9168
28156 = 4×7039
28651 = 7×4093
30296 = 7×8×541
30576 = 8×42×91
30752 = 4×8×961
31920 = 5×76×84
32760 = 8×45×91
32890 = 46×715
34902 = 6×5817
36508 = 4×9127
47320 = 8×65×91
58401 = 63×927
65128 = 7×9304
65821 = 7×9403
(Thanks, Hans.)
Constitutional Crisis
From Lee Sallows:
(Thanks, Lee!)
Outcry
A curious observation by a British ornithologist during World War I:
The Zeppelin raids … were nearly always heralded in this country by the crowing of pheasants, and the sensitiveness of this species to distant sounds was frequently a subject of comment. There seems no reason to suppose that pheasants have keener powers of hearing than men; it appears more probable that these birds are alarmed by the sudden quivering of the trees, on which they happen to be perched, at the time of an explosion … During the first Zeppelin raid in January 1915, pheasants … thirty-five to forty miles from the area over which the Zeppelins flew, shrieked themselves hoarse. In one of the early battles in the North Sea … Gamekeepers on the east coast used to say that they always knew when enemy raids had commenced, ‘for the pheasants call us day and night’.
On the Western Front, a starling learned to imitate the whistle that warned of enemy aeroplanes. One artillery officer wrote, “It was great fun to see everyone diving for cover, and I was nearly deceived myself one day.” A gun commander wrote of an owl, “The beastly bird learnt to imitate the alarm whistle to a nicety; on several occasions he turned me out in pyjamas and, when the crew had manned the gun, gave vent to a decided chuckle.” See Onlookers.
(Joy Damousi, Deborah Tout-Smith, and Bart Ziino, eds., Museums, History and the Intimate Experience of the Great War, 2020.)
The Peirce-Putnam Paradox
Divide line interval AD at point P and separate the halves by a short distance.
What’s happened to point P? Did it become point B or C? It seems wrong to say that it’s neither of these, or that it’s only one of them.
But if the single point P has “become” the two points B and C, how can we say it was a dimensionless object?
(Hilary Putnam, “Peirce’s Continuum,” in Kenneth Laine Ketner, ed., Peirce and Contemporary Thought: Philosophical Inquiries, 1995, via Piotr Łukowski, Paradoxes, 2011.)
Keep Away
A notable adaptation: The forewing tips of the Atlas moth, Attacus atlas, resemble the heads of snakes.
When the moth encounters predators in its native Asian forests, the movement of its wings exaggerates the resemblance.
Fair and Square
From Lee Sallows:
(Thanks, Lee!)
Spuds Illustrated
I just found this visual explication of the potato paradox — if potatoes are 99 percent water by weight, and you start with 100 pounds of potatoes and let them dehydrate until they’re 98 percent water, what’s their new weight?
The surprising answer is 50 pounds. Blue boxes represent water, orange non-water. So to double the share of the non-water portion we have to halve the amount of water.
(I had thought it was the setting that made this so confusing, but it turns out real potatoes are 80 percent water! So it’s not as outlandish as I’d thought.)