Monday, 29 December 2014

New Blog Location

Future blog posts can be found here.

Tuesday, 9 December 2014

Some nice mathematical books

People often stop me in the street and say: "You are Brady from Numberphile. Can you recommend a good mathematical book for Christmas!"

This is entirely untrue. It has never happened.

However I will use this blog post to recommend some books written by people from Numberphile videos.

This list of not exhaustive, just a few that sprang to mind while I was waiting for my computer to process a video.

Matt Parker's shiny new "Things to Make and Do in the Fourth Dimension" is cracking - very funny like the man himself.

You can buy on Amazon in the UK and US - or get a signed copy from Matt.

Simon Singh's The Simpsons and Their Mathematical Secrets - great hidden gems from the TV show (plus Futurama).

Simon's other books are great too - check him out on Amazon, etc.

Alex Bellos - of cake cutting fame - has got Alex Through the Looking Glass (aka Grapes of Math). It is the sequel to Alex's Adventures in Numberland (aka Here's Looking at Euclid).

Ed Frenkel has Love & Math - well worth a look.

Ron Graham - yes, that Graham - has Magical Mathematics written with Persi Diaconis (Persi is coming to Numberphile soon!)

Barry Mazur does great books too.

That'll do for now... Will add some more later perhaps.

Clearly I am biased towards Numberphile contributors - what did you expect!?

Monday, 24 November 2014

Help with a Selfie

If you are a scientist, science student, teacher or somehow involved in science, we need your help.

We are collecting "science selfies" of people from Commonwealth countries.

Professor Martyn Poliakoff would like to use them in a video which will be shown at his address at the Commonwealth Science Conference 2014 being held in India.

See his explanation here:

If you can help, here are some pointers:

Email: with SELFIE in the subject field to help us sort them.

- It is good if the photos looks like a selfie rather than anything too pro!

- Please include a name, country and what you do in the email too. This is important. It's okay if you don't want a surname to appear.

- Show us in your science environment (lab, classroom, outdoors?) if you can.

- The pics will be used in The Prof's video plus the video will appear here on our YouTube channel.

- Sorry if we can't use them all.


Friday, 31 October 2014

Matt Parker's Book

Numberphile regular Matt Parker - aka Standupmaths - has a new book out.

It's called Things to Make and Do in the Fourth Dimension.

I really recommend it.

Matt gives a lot of time and energy to Numberphile, and his main reward is enduring the mixed bag of YouTube comments! :)

So it's at rare times like this we can give something back by showing support.

But the main reason you should buy his book is because it's really good.

Like a series of really good, funny Numberphile videos in written form. So without my dodgy camerawork and editing! :)


A signed copy direct from Matt.

Amazon US.

Amazon UK.

Or buy it from a book shop... Apparently they are a thing.

The book looks like this in the UK and US.

Thursday, 9 October 2014

2014 Nobel Prizes

Every year we do videos for the Nobel Prizes in chemistry and physics.

It is always bit of a mad scramble to find someone who might have something to say at really short notice!

Here are this year's, from Sixty Symbols and Periodic Videos.

Monday, 22 September 2014

The First 100 Brady Numbers

Just posted a video in which The Brady Numbers came into existence!!!

I see they have made it onto Wikipedia, although who knows for how long?

Thanks to viewer Marek who subsequently got in touch and sent me this list of the first 100 Brady Numbers.

1. 2308
2. 4261
3. 6569
4. 10830
5. 17399
6. 28229
7. 45628
8. 73857
9. 119485
10. 193342
11. 312827
12. 506169
13. 818996
14. 1325165
15. 2144161
16. 3469326
17. 5613487
18. 9082813
19. 14696300
20. 23779113
21. 38475413
22. 62254526
23. 100729939
24. 162984465
25. 263714404
26. 426698869
27. 690413273
28. 1117112142
29. 1807525415
30. 2924637557
31. 4732162972
32. 7656800529
33. 12388963501
34. 20045764030
35. 32434727531
36. 52480491561
37. 84915219092
38. 137395710653
39. 222310929745
40. 359706640398
41. 582017570143
42. 941724210541
43. 1523741780684
44. 2465465991225
45. 3989207771909
46. 6454673763134
47. 10443881535043
48. 16898555298177
49. 27342436833220
50. 44240992131397
51. 71583428964617
52. 115824421096014
53. 187407850060631
54. 303232271156645
55. 490640121217276
56. 793872392373921
57. 1284512513591197
58. 2078384905965118
59. 3362897419556315
60. 5441282325521433
61. 8804179745077748
62. 14245462070599181
63. 23049641815676929
64. 37295103886276110
65. 60344745701953039
66. 97639849588229149
67. 157984595290182188
68. 255624444878411337
69. 413609040168593525
70. 669233485047004862
71. 1082842525215598387
72. 1752076010262603249
73. 2834918535478201636
74. 4586994545740804885
75. 7421913081219006521
76. 12008907626959811406
77. 19430820708178817927
78. 31439728335138629333
79. 50870549043317447260
80. 82310277378456076593
81. 133180826421773523853
82. 215491103800229600446
83. 348671930222003124299
84. 564163034022232724745
85. 912834964244235849044
86. 1476997998266468573789
87. 2389832962510704422833
88. 3866830960777172996622
89. 6256663923287877419455
90. 10123494884065050416077
91. 16380158807352927835532
92. 26503653691417978251609
93. 42883812498770906087141
94. 69387466190188884338750
95. 112271278688959790425891
96. 181658744879148674764641
97. 293930023568108465190532
98. 475588768447257139955173
99. 769518792015365605145705
100. 1245107560462622745100878

And here is a list of the first 337 from "Yeelk".

Wednesday, 17 September 2014

I quit my job for Physics

Recently received this amazing message from viewer Filipe (pictured):

Dear Brady, Hi. 

My name is Filipe (or Philip) and I live in Brazil. 

Two years ago aprox, I was working at an Investment Company in São Paulo. 

I was very unhappy with my current job. I was working insane hours and doing a job that I didn’t love.  I graduated as an engineer and I love Physics and Maths. But I wasn't doing any of that. 

Long story short: I saw your videos, particularly Sixty Symbols. They inspired me to change my life around. I decided to try going for a PhD. 

Everybody said I could not do it because I was already 3 years in the investment industry and it has been a long time since I had formally studied all the Maths and Physics. 

I decided to ignore these people. 

I quit my job, spent most of my savings on 30 day trip to England. 

I wanted to do a PhD in Physics. I travelled to meet people at the top universities (Cambridge, Oxford, Kings, Imperial, Nottingham...) and talked to everyone I could about my situation. 

In Nottingham I talked for hours (on several different days actually) with Prof Roger Bowley. Emailed Prof Martyn and talked with Prof Tony Padilla and with Samantha. 

And had a brilliant interview with Professor Philip Moriarty. I explained to him what I want to do. He said that he had just the exact idea and was waiting for the right person. 

I received and bunch of offers and I’m starting my PhD 1st of April at University of Nottingham. Philip is going to be my Supervisor. 

My whole life is changing. My girlfriend is considering doing a PhD as well in Medicine at Nottingham and my family is planning to move in to England the next year as well. 

I would very much like to thank you. 

The videos (Numberphile, Periodic Videos, Deep Sky Videos and Sixty Symbols) were the spark I needed to re-ignite the passion. 

Hope to see you some time over the next 4 years in Nottingham and get to say Thank You personally. 

Yours Faithfully Filipe

(Partly edited for privacy, style, etc, and reproduced with Filipe's permission)

Saturday, 13 September 2014

Fire in Nottingham

So many people have asked about this, I thought I'd write a generic response.

Last night (12 September) a new chemistry building at the University of Nottingham was destroyed by fire.


It was a horribly spectacular blaze tackled by 60 firefighters.


The building was under construction, about 70% complete. It happened at night and no-one was hurt.

It was not the university's main chemistry building, where we film Periodic Videos.

In fact the new building was on a separate but nearby campus.

However everyone in the chemistry department was looking forward to using the new labs. Our very own Professor Pete Licence was to oversee their operation.

Artist's impression

It is too early to know how the fire started and what will happen next.

We had been meaning to make a film about its construction and, in fact, had recently scheduled a film shoot but cancelled at the last minute.

I sincerely hope the project starts again and we get to make that film!

PS: The destroyed building was the "GlaxoSmithKline Carbon Neutral Laboratory for Sustainable Chemistry". More at this link.

PPS: University statement.

Friday, 5 September 2014

Pride and Prejudice (and Mathematics)

The most recent Numberphile video about Stable Marriages uses the protagonists from Pride and Prejudice as a key example.

I think some people do not realise this.

And many more do not realise artist Pete McPartlan based his depictions of characters from the BBC adaption.

I requested this because I LOVE the BBC version.

I believe Pete had not seen it, but watched some episodes before starting his work. I think I converted him!!!!

See pictures below.







Wickham (boo!)


Thursday, 21 August 2014

Science and Intuition - A Collection of Quotations

The most recent Sixty Symbols video was bit of a departure from the standard fare.

Philosopher Jonathan Tallant discusses the role of intuition - or gut feelings - in science.

It is an interesting debate. To what extent should scientists make decisions based on intuition?

There are arguments for and against. Many of these have been appearing in the comments section.

It also raises questions about what is really meant by "intuition".

Here is the main video on Sixty Symbols.

And the interview continues on my occasional philosophy channel, PhilosophyFile.

As part of my preparation, I had some special friends collect some quotes about science and intuition.

I did not use them in the video, but they are well worth sharing. Thanks to the people who found them. Quote finding fiends!

I believe in intuition and inspiration. Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution. It is, strictly speaking, a real factor in scientific research. 
— Albert Einstein Cosmic Religion: With Other Opinions and Aphorisms (1931), 97.

The intellect has little to do on the road to discovery. There comes a leap in consciousness, call it intuition or what you will, and the solution comes to you and you don’t know why or how. 
— Albert Einstein Quoted in Forbes (15 Sep 1974). In Larry Chang, Wisdom for the Soul (2006), 179.

The supreme task of the physicist is to arrive at those universal elementary laws from which the cosmos can be built up by pure deduction. There is no logical path to these laws; only intuition, resting on sympathetic understanding of experience, can reach them. 
— Albert Einstein Address (1918) for Max Planck's 60th birthday, at Physical Society, Berlin, 'Principles of Research' in Essays in Science (1934), 4.

It is by logic that we prove, but by intuition that we discover. 
— Henri Poincaré In Science and Method (1908) translated by Francis Maitland (1914, 2007), 129.

I’m supposed to be a scientific person but I use intuition more than logic in making basic decisions. 
— Seymour R. Cray In transcript of a video history interview with Seymour Cray by David K. Allison at the National Museum of American History, Smithsonian Institution, (9 May 1995), 30.

My view of the matter, for what it is worth, is that there is no such thing as a logical method of having new ideas, or a logical reconstruction of this process. My view may be expressed by saying that every discovery contains an 'irrational element,' or 'a creative intuition,' in Bergson's sense. In a similar way Einstein speaks of the 'search for those highly universal laws ... from which a picture of the world can be obtained by pure deduction. There is no logical path.' he says, 'leading to these ... laws. They can only be reached by intuition, based upon something like an intellectual love (Einfühlung) of the objects of experience.' (1959) 
— Karl Raimund Popper The Logic of Scientific Discovery: Logik Der Forschung (2002), 8.

Notion without intuition is empty, intuition without notion is blind. 
— Immanuel Kant In Ralph Keyesr, The Quote Verifier, 52.

Science does not mean an idle resting upon a body of certain knowledge; it means unresting endeavor and continually progressing development toward an end which the poetic intuition may apprehend, but which the intellect can never fully grasp.
— Max Planck In The Philosophy of Physics

Thoughts without content are empty, intuitions without concepts are blind... The understanding can intuit nothing, the senses can think nothing. Only through their union can knowledge arise. 
— Immanuel Kant Critique of Pure Reason (1781), trans. Norman Kemp Smith (1929), 93.

Monday, 4 August 2014

Numberphile2 FAQ

Okay, here are some answers to frequently asked questions about my YouTube channel Numberphile2.

1. What is Numberphile2?

It is the second or supplementary channel to Numberphile.

2. What is it for?

It is designed to host Numberphile material that I do not want to put on "main channel" for various reasons.

3. What sort of material is that?

It could be anything. Mainly it is "extra material" cut from Numberphile videos. It could also just be stuff that I thought did not quite belong on the main channel or behind-the-scenes stuff. Maybe it is too niche, too long, too short, etc.

4. But I love seeing all that stuff, why not just put that on Numberphile?

Because Numberphile has a large following (about one million subscribers) and casual viewers do not want their feeds clogged up with "extra material" or 2-3 videos every time I put something new out. They just want the headline act.

Numberphile2 can be a channel for the real die-hards who want everything. Like a little club for the true believers! :)

5. Why not just put that "extra stuff" on Numberphile (main) and make it unlisted?

I used to do that, but the material then becomes impossible to find in searches. And some people do want to be able to have this turn up in a subscription feed in some form so they don't miss it.

6. Then why is some material on Numberphile2 still marked as unlisted?

There are a few reasons that Numberphile2 videos START as unlisted and become listed later.... The main one is this: When I release a new video on Numberphile, I probably release the "extra material" at the same time and link to it from the main video. If I made them both listed, they would turn up in subscription feeds around the same time, increasing the chances that people might watch them in the wrong order. To get around this, I make the second video unlisted so it does not show in sub feeds... I then list it a few day later.

7. Why is the logo/avatar for Numberphile2 the number 2 and not Tau?

The current avatar for Numberphile is Pi on a brown paper background - a famous "number" everyone recognises and it just looks cool. Now because Tau is 2Pi, many people think that should be the logo for Numberphile2. I agree that people who "get the joke" would appreciate that. But I think it would be confusing for people who do not. For a start, Pi has two "legs" and Tau has one. Some people might think Pi should be the second channel logo? The number two is just really clear and obvious... It says: "This the second channel". Sometimes it is best to not be too clever.

Should I subscribe to Numberphile2?

In some ways, my advice to casual viewers is "no". I will usually link to Numberphile2 material from main videos, either via links or annotations.
I will also let people know about anything great on Numberphile2 via Facebook and Twitter.
However if you are really into all the extra stuff and not want to miss anything, than of course please do subscribe. I appreciate all the support!

Monday, 7 July 2014

Slicing cake all over the place

We made this Numberphile video...

Then this happened:

Hear a discussion about this - and viral videos in general - on Episode 15 of Hello Internet.

Saturday, 31 May 2014

Special Roll

From a viewer named Patti...

My class has been studying probability and yesterday we calculated the probability of rolling a Yahtzee on the first roll.  
So, today, we watched your video.  
The students were intrigued and waited for that Yahtzee with close attention.  After the video, I told them, like you said, in the game Yahtzee, you get three tries.  
So I rolled five dice...and got a Yahtzee!  
The class and I were stunned.  Utter silence and disbelieve.  
The look of "did that really happen"  on 30 7th grade faces.  
Thank you for showing the students your perseverence of waiting through 600 some trials.  
And thank you for making my roll look so special!!

Wednesday, 7 May 2014

Net Neutrality

It's a big deal in the US (and the world) at the moment!

Two recent videos from CGP Grey and Vi Hart are well worth watching (and maybe acting upon?)

This video by Emily from BlinkPopShift from a while ago was also good.


Oh, I missed this excellent video on the topic by Hank Green.


And now here is Mike Rugnetta from PBS Ideas Channel

And the excellent John Oliver piece...

About 100 people sent me the John Oliver piece after we discussed Net Neutrality of EPISODE 12 OF HELLO INTERNET


Friday, 2 May 2014

Hello Internet Podcast

Not been very active on the blog just lately.

Guess that's because I've been busier than usual.

Plenty of new videos have been coming out - will list some of the better ones below.

Some of you may also know I've started working on a new podcast with CGP Grey called Hello Internet.

I've known Grey for a few years now.  He has even cameoed in a few of our videos, most memorably this one.

The podcast has been great fun so far (we've recorded 11 at the time of posting).

The best way to follow the podcast is via things like iTunes and RSS, etc… More details are at the Hello Internet website.

We really discuss everything - but I guess a major theme is life as YouTube film-makers.

Other important topics have included education, freebooting and plane crashes!

Our latest move has been putting the podcasts on a Hello Internet YouTube channel.

These are obviously a bit behind the general release of the audio podcasts, but another way to digest the show!

Anyway, back to may "day job".

Here are just some of the videos to come out in recent weeks.

Tuesday, 8 April 2014

Favourite Numbers - 7 wins again

A poll by author Alex Bellos has found, unsurprisingly, that seven is the world's favourite number!

He's released the results to coincide with his new book - Alex Through the Looking-Glass.

Numberphile had its own, less formal poll a while back.

It started with this video:

And then we harvested the stats to make this one:

Seven won that poll also.

Here are some previous appearances by Alex on Numberphile…

And his first book is Here's Looking at Euclid (aka Alex's Adventures in Numberland).

Friday, 4 April 2014

Alan's Album

Regular viewers will be familiar with the music of Alan Stewart.

Alan is a physics teacher who composes and performs music in his spare time.

I love his work and we've collaborated together on MANY videos, some of which are listed below.

Well, Alan was too humble to tell me, but he has pulled together many of his best tracks into an album on iTunes.

Here is the link.

I think it's great value.

Despite having many of them on my computer already (for obvious reasons), I downloaded the album myself last night and have been listening non-stop.

Gorgeous background music.

I especially recommend the tracks "Time Passes" and "Wait" - but maybe that is because they appear on some of my favourite videos.

(As a bonus, Alan included his Good Will Hunting inspired track, which is often requested!)

Dominoes as a Computer

Two Numberphile videos and Matt's own…


Thursday, 27 February 2014

I need your Numberphile Selfie

I am giving a talk tomorrow night and would like to show some pictures of real Numberphile viewers.

(Because although I love them, you are more than just numbers to me!)

You can help by sending me a "selfie-style snap" of you watching Numberphile (maybe a favourite presenter on screen, a video you liked or hated, etc).

The picture will be used in my talk and, unless you tell me otherwise, I might put some of them here on the blog?

Email to numberphile at gmail dot com

Include as much or as little information as you like... I'd love to know your name, where you are, maybe why you watch the videos... and your favourite number.  You can include nothing or write me an essay - the pic is the crucial bit.

I will reply to all of them (unless you tell me not to!)

Here's a just a sample photo, but be as creative or simple as you like.

Thanks for helping. I hope it makes my talk a little more interesting.


Friday, 7 February 2014

A Feast for the Senses

Posted two videos today - one for the ears and one for the eyes!

The Sound of Atoms Bonding

Hydrogen Bubbles Exploding

Friday, 31 January 2014

Three in a row

Just because it was how things worked out, three videos went up today across three of our channels…

Magnesium in Water on periodicvideos:

An epic discussion of Stephen Hawking's latest views on Black Holes for sixtysymbols:

And even more epic computerphile video about fonts:

Ruler of the Universe

Introducing The Ruler of the Universe.

A limited edition have been created at the University of Nottingham, where I work with scientists to create Sixty Symbols and Deep Sky Videos (among other things).

Just over 30cm of geeky pleasure

Featuring a cm and a log scale

Professor Mike Merrifield with the prototype

 From the planck scale to the size of the observable universe

The backside features physical constants

My favourite bit a sixtysymbols plug!!!

A health warning!

The rulers have been produced for fun but also to promote the University of Nottingham's excellent School of Physics & Astronomy.

At this stage the plan is to mail them to Year 12 students who have shown an interest in studying physics at Nottingham (via UCAS).

Some will also be handed out to be people visiting the university for open days.

I will try to get my hands on a few for sixtysymbols viewers, but no guarantees.

You could try following Professor Merrifield on Twitter too - maybe he will tell us more when the main batch arrives!?

Monday, 27 January 2014

Supernova in M82

A supernova in "nearby" M82 is one of the closest in recent years.

There are great images everywhere of SN2014J, and we have done a short film for Deep Sky Videos (see embed below).

I emailed UK astrophotographer Nik Szymanek - who features in some of our videos - to ask if he had grabbed an image.

Despite some cloudy nights, he managed to get this one:

Another friend of ours (and a world-class imager) is Pete Lawrence (of green flash fame).

Again, the supernova was not a priority for Pete, but he did manage to grab this image:

Here's the video we put on Deep Sky Videos a day or two after the news broke:

Some great stuff about the supernova can be found here.

Thursday, 16 January 2014


It was almost inevitable, after days of mind-numbing animation, that I would make a mistake in my recent Knight's Tour video

And indeeed I made an error showing the path of magic knight's tour, making a mis-step over the final few moves… 61-62-63-64.

This one, from the video, is wrong (it is legitimate tour, but not quite magic):

And this one is right (I think):

Each column and row should add to 260.

Here are some great resources from people who really know there stuff when it cmes to Knight's Tours…

Some good knight's tour links:
Great overview by Ben Hill and Kevin Tostado:
Notes and huge resource by George Jelliss:
On using "ants" to find tours:
Good stuff on magic knight's tours:
On the number of knight's tours:

Sunday, 12 January 2014

Thanks for the messages


Dr Tony Padilla has written his own response - read it here.

And here is a New York Times article on the video.

(And see Terry Tao's blog on this topic and analytic continuation, etc)

This is a general response to people who have messaged and emailed about our 1+2+3 video… Trying to cover a few general points rather than reply to everyone individually!

1. Firstly, thank you for taking the time to message and (in most cases) being so polite and constructive. It is great that the Numberphile audience is so passionate.

2. I think many people have not watched the second, more detailed video. I would suggest it before firing off a lengthy email.

3. For those taking issue with 1-1+1-1 etc, I would also suggest watching our video on Grandi's Series.

4. The concepts in these videos include some more obscure techniques, such as Analytical Continuation and Ramanujan Summation. It is worth reading about them.

5. There is a Wikipedia article on 1+2+3+4. Check it out.

6. Numberphile is not mathematics text book.  In a short video for a popular audience you should not expect the level of detail and background explanation possible in a tome that is hundreds of pages long. Also some topics covered in the videos may involve numbers in our lives without necessarily being mathematical!

7. These are unscripted interviews. There's little point getting upset about imprecise or layman's language… I would hate to change that informal and spontaneous format. I know some of you have a PhD is mathematics and know this stuff back-to-front… But spare a thought for those who do not.

8. We often look at some advanced, obscure and controversial topics. There's no denying that some physicists do use this -1/12 result, whatever you may think of it.

DR TONY PADILLA (featured in the videos) has written a further article - here is a link.


9. On the topic of Divergent Series, the Wikipedia article is very good and I'm also advised that Chapter XIII of Konrad Knopp's book "Theory and Application of Infinite Sequences and Series" is excellent if you can find it.

10. You should NEVER disregard what your teachers or professors tell you (especially if they are setting yours tests and exams) - but it can be fun hearing what professional people are doing and the techniques they use?

11. Apparently this play - A Disappearing Number - is partly based on the result. I'm told it's quite good.

Most importantly just remember, it is a YouTube video. It is supposed to be fun and thought-provoking. Don't get upset.

Many people send very long and detailed emails… I really appreciate this but please bear in mind that a) I cannot answer them all and b) I am not a professional mathematician (though many of the interview subjects are).

A great place to leave your comments, ideas and arguments is in the YouTube comments where other people will see them, and maybe share their own views.

(An aptly-named meeting room at YouTube offices)

Thursday, 9 January 2014

"Astounding Result"

The latest Numberphile video is about the sum of 1+2+3+4 all the way to infinity.

The proof is surprising (and a bit controversial, judging by the viewer comments):

I filmed this with Dr Tony Padilla from the University of Nottingham

There's a second video (currently unlisted) in which Profesor Ed Copeland proves the same thing in a different way.

This second video also has extra footage cut from the original with Tony!

I always find it fun to see how many people follow links from the main video (which as gone to all the usual subscribers) and watch the "hidden extras".