Calculating Pi
Watch four different ways to calculate Pi with Numberphile.
Starting with the most recent video, Holly Krieger uses the Mandelbrot Set.
Tony Padilla uses matches (instead of needles).
Want more Pi videos? We have you covered.
Face to Face
The latest Objectivity video deals with two "death masks" stored at the Royal Society.
They are casts of the faces of two great men in the fields of maths, astronomy and physics.
Isaac Newton died in 1727 and James Jeans in 1946.
Newton's death mask is well-known - in fact I've filmed it before.
Newton's face was cast at time when such things were common.
For example, they were useful tools for sculptors making posthumous statues.
The James Jeans mask is unusual because it is more modern.
Its creation was discussed between Jeans' wife, Susi, and family friend Joy Adamson.
The pair were present when Jeans died and wanted to capture the "spiritual radiance" of his face.
The mask spent many years in the Jeans home, but has now been entrusted to the Royal Society.
You can read more about it on the society blog.
Alkali Metals Underwater
A recent series of three videos in which Neil's strange "Test Tube Torturer" was used to break open ampoules of Alkali Metals.
For more alkali metal action - including more water reactions - see this playlist.
Official T-Shirts of Official Things
UPDATE (28 September): T-Shirt designs have been slightly amended to move the logo higher on the chest. We'll also be extending the sale deadline to October 5 to accommodate people who only learn of the shirts in episode 48. Sorry to anyone inconvenienced.
Despite CGP Grey's initial resistance, The Hello Internet Podcast now has an official bird and official rice rat.
I think it is entirely possible that we're the first podcast to appoint an official rice rat.
For a full explanation, listen to episode 47 (discussion from 1h33min onwards).
The chosen rice rat is the now extinct Jamaican Rice Rat.
And, controversially, our official bird is the Reunion Swamphen (not the African Penguin).
To mark the occasion, why not snap up one of these commemorative official T-shirts. Wear it with pride and tweet Grey a picture of it!
Various colours and designs available to suit your taste and gender.
More discussion of the t-shirt here at the start of episode 48.
Postcard Recipients
Some pictures from Numberphile fans who received our "89" postcard.
It's a limited edition of 89, but there are still a few left.
They deliberately come through the normal post without an envelope, so get all sorts of nice stamps and cancellation marks!
@dan_lapsley was happy to get 55 - a palindrome!
@PAShanky was pleased to get 42
Simon in Switzerland
Lance in San Diego
@mathslinks may frame this one
Here's the video which the postcard is from...
Portuguese Subtitles
Our friend Luis Brudna, from Brazil, has translated MANY of our Periodic Videos.
We met Luis when we went to Brazil
In fact it is no longer feasible for me to keep a playlist of his many translations.
But here are the latest seven, just added today.
Strange Australians?
There was a time when Europeans had no idea what people around the world would look like.
Maybe they'd look like this, with giant feet they could use to shelter from the sun?
This image is contained within Margarita Philosophica, a famous text book from the early 1500s.
We looked at various editions of the book at the Royal Society for Episode 34 of Objectivity.
And with the summer of cricket rivalry at its height, it was unsurprising that librarian Rupert Baker (an Englishman) used the strange depictions to poke fun at me (an Australian).
