The doomsday algorithm
Want to work out what day of the week for any date? Just use the doomsday algorithm.
Category: Mathematics & statistics
The scientists of Mars
When asked why we have no proof of extraterrestrial life, the Hungarian physicist Leo Szilard joked that Martians were already among us… they just called themselves Hungarians.
Cryptographic magic
Steganographia is a late 15th / early 16th century German book of magic… but it’s not actually about magic.
Don’t trust the small numbers
In mathematics, the Pólya conjecture is true for every natural number up to 906,150,256… and then it’s not.
Abnormal normal dice
A pair of Sicherman dice have numbers ranging from 1 to 8 on their faces, but roll two of them together and they produce the same totals as a pair of normal dice.
Experimental pi
If you have a piece of striped paper and some sticks, you can estimate the value of pi through a simple experiment.
Will Rogers paradox
Someone (not Will Rogers) once joked that “When the Okies left Oklahoma and moved to California, they raised the average intelligence level in both states.” This quirk of statistics has some surprising implications for cancer survival rates.
The Yale blackboard rebellion
In 1830, nearly half of the mathematics class at Yale was expelled for refusing to use a blackboard in their exams.
Da Vinci’s fractal trees
Leonardo da Vinci observed that tree branches together are always as thick as the trunk beneath them. This is true, and there are some good ideas why.
Cosmic ladder (Part 2)
To measure distances in deep space, you need to look for candles in the darkness. [2 of 2]
Cosmic ladder (Part 1)
It’s a lot more difficult to measure distances in space than you might think. [1 of 2]
Ghost leg
Ghost leg is a technique to randomly match up two groups – assigning a list of chores to a list of people, for example. And all you need is a drawing of a ladder.
Mathematical collective
Since 1939 an author named Nicolas Bourbaki has published a series of volumes on pure mathematics. But Bourbaki does not exist.
Math homework
In 1939 a student at UC Berkeley copied down two homework problems from the class blackboard. He solved them in a few days… and then discovered that they were two of the thorniest unsolved theorems in statistics.
Mathematical coincidence
A billionth of a century is approximately pi seconds. The diameter of the Earth is roughly half a billion inches.
The birthday paradox
Put 70 people in a room and there’s a 99.9% chance that two of them share a birthday. Why?