Blind Dates

stover calendar trick

A calendar curiosity by Canadian magician Mel Stover:

Offer any month’s calendar to a friend and have him outline a 4×4 square of dates. Ask him to circle any date in that square and cross out the other numbers in its row and column. Have him do this three more times and then add the circled numbers.

You can predict his answer by totaling the numbers in either pair of diagonally opposite corners in the square and doubling that number. Why does this work?

Near Thing

‘Well, do you know the one,’ I began, ‘in which two geologists converse in a cafe? One of them says: ‘Yes, unfortunately fifteen billion years from now the Sun will cool, and then all life on Earth will perish.’ A card-player nearby has been half listening to the joke, and turns in terror to the geologist: ‘What did you say? In how many years will the Sun cool?’ ‘Fifteen billion years,’ the scientist replies. The card-player lets out a sigh of relief: ‘Oh, I was afraid you said fifteen million!’

— László Feleki in Impact of Science on Society, 1969

“The High Standard of Education in Scotland”

We were staying in Ballater, a small town on Deeside in Scotland. In the town was a tiny shop which sold tourist attractions and picture postcards, and in its minute window was a very fine specimen of smoky quartz material. Buying a postcard, I said to the proprietor, ‘That’s a fine group of smoky quartz in your window’ and had this reply in very broad Scotch:

‘That’s no smoky quartz, that’s topaz. It’s a crystal. You can tell crystals by the angles between their faces. If you’re interested I’ll lend you a book on the subject.’

I knew enough (crystals being rather in my line) to be sure it was smoky quartz, and on return to base looked up a book on Mineralogy which said ‘Smoky Quartz, also known as Cairngorm, is called Topaz in Scotland.’

— Sir W.L. Bragg, quoted in R.L. Weber, A Random Walk in Science, 1973

In a Word

http://commons.wikimedia.org/wiki/File:L-Ascorbic_acid.svg

nescience
n. ignorance; lack of knowledge

agnoiology
n. the study of ignorance

In 1927, Hungarian physiologist Albert Szent-Györgyi isolated a substance in lemons and oranges that seemed to prevent scurvy.

He couldn’t identify it chemically, so he called it “ignose,” meaning “I do not know.”

When the editors of the Biochemical Journal asked for a different name, Szent-Györgyi suggested “godnose.” Finally they settled on “hexuronic acid.”

It turned out to be vitamin C.

Magic

From Royal V. Heath, Scripta Mathematica, June 1952:

heath magic square

In the square above, all rows, columns, and diagonals produce the same sum. And:

16 + 11 + 13 + 10 = 9 + 14 + 12 + 15
16 + 17 + 14 + 3 = 11 + 22 + 9 + 8
2 + 15 + 20 + 13 = 5 + 12 + 23 + 10
16 + 5 + 17 + 12 = 20 + 9 + 13 + 8
2 + 11 + 15 + 22 = 14 + 23 + 3 + 10
10 + 16 + 17 + 23 = 11 + 13 + 20 + 22
2 + 8 + 9 + 15 + 11 + 13 + 20 + 22 = 3 + 5 + 12 + 14 + 10 + 16 + 17 + 23

Most remarkably, everything above holds true if you square each term.

A Balanced Diet

http://en.wikipedia.org/wiki/File:Santorio_Santorio_balance.jpg

In studying metabolism in the early 1600s, Santorio Santorio undertook a unique study: He conducted his daily activities on a platform attached to a steelyard scale. After years of readings, he learned that his food always weighed more than his excretions, and concluded that the rest was lost through “invisible perspiration,” the loss of matter through the pores and breath.

Santorio’s conclusions remained the state of the art for more than a century. When Ben Franklin wrote in 1742, “If thou art dull and heavy after Meat it is a sign that thou hast exceeded due measure,” he was essentially repeating Santorio’s aphorism of 150 years earlier, “Meats which promote Perspiration bring Joy, but those which obstruct it Sorrow.”

Overtime

http://commons.wikimedia.org/wiki/File:Robert_Williams_Wood.png

How to clean a 40-foot spectrograph, from R.W. Wood’s Researches in Physical Optics, 1913:

“The long tube was made by nailing eight-inch boards together, and was painted black on the inside. Some trouble was given by spiders, which built their webs at intervals along the tube, a difficulty which I surmounted by sending our pussy-cat through it, subsequently destroying the spiders with poisonous fumes.”

This was the least of Wood’s exploits. Walter Bruno Gratzer, in Eurekas and Euphorias, writes that the physicist “would alarm the citizens of Baltimore by spitting into puddles on wet days, while surreptitiously dropping in a lump of metallic sodium, which would explode in a jet of yellow flame.”

Topsy Turvy

http://commons.wikimedia.org/wiki/File:Earth%27s_magnetic_field,_schematic.svg

The north pole is the south pole. Earth’s north magnetic pole is actually the south pole of its magnetic field — a compass needle points “north” because opposites attract.

(Thanks, Jeremy.)

The Figure 8 Puzzle

figure 8 puzzle

Can this loop of string be freed from its wire? Stewart Coffin, who devised the puzzle in 1974, writes, “I soon became convinced that this was impossible, but being a novice in the field of topology, I was at a loss for any sort of formal proof.” He published the challenge in a newsletter and has been receiving requests for a solution ever since. Adding to the confusion, in 1976 a British puzzle editor mistakenly claimed with that Coffin’s creation was equivalent to another puzzle with a known solution, and Pieter van Delft and Jack Botermans published an amusingly bewildering “solution” of their own in their 1978 book Creative Puzzles of the World.

In the meantime, fans around the world have continued to experiment, and mathematicians Inta Bertuccioni and Paul Melvin have both offered proofs that the puzzle is unsolvable. “Whoever would have guessed that this little bent piece of scrap wire and loop of string would launch itself on an odyssey that would carry it around the world?” Coffin writes. “Will it mischievously rise again, perhaps disguised in another form, as topological puzzles so often do?”