The Numberphile Podcast

I speak with many fascinating people while making Numberphile videos.

So it seems to make sense to have a podcast where I can talk to them in more depth.

The first episode is an interview with fellow math YouTuber, Grant from 3blue1brown.

Plenty more coming, including fun episodes Hannah Fry and Cliff Stoll --- plus all sorts of world-famous mathematicians.

Podcast webpage:

Please do subscribe on your podcast player.

Another Periodic Videos Top 10

For Periodic Videos’s 10th anniversary, we published “top ten” lists by both myself and Professor Sir Martyn Poliakoff.

Here’s another top 10 supplied by one of our viewers and a good friend of the show, Andres Tretiakov. He’s a technician at an English school and a real chemistry enthusiast.

 Andres and The Prof

Andres and The Prof

He avoided any duplication with videos on mine or Sir Martyn’s list…

Tsar's Vodka and Gold

I love Aqua Regia and especially all the history and alchemy associated with it. The red colloidal solution or sol of gold nanoparticles at the end also demonstrates that red stained glass in churches contained gold nanoparticles.


Neil compilation: because he is the MASTER and I can only aspire to be like him.

Carbon Dioxide Cannon

 Because by making mistakes science moves forward!!!

Periodic Table Clock (12 Days of Christmas)

The whole series of the 12 Days of Christmas is a pleasure to watch. It really shows just how far away Periodic Videos has reached and the wonderful response of the fans that love chemistry across the globe. In addition, it made me reach out to Nagayasu Nawa and congratulate him for such beautiful artwork, clocks, fans and PT Happi. Since then, we have exchanged gifts, ideas and suggestions for a few years now and I consider him a good friend thanks to Periodic Videos.

Fire Water

Any reaction involving potassium metal is a favourite of mine. Here Sam Tang showed me a really cool demo that I have used many many times and for that I’m very grateful! It’s beautiful and there is so much chemistry going on!


 Not only this one but ALL the videos involving trips around the world where the Prof held meetings, sharing and discussing chemistry in a more personal approach.

Dynamite and TNT

Being an enthusiast of high energetic materials I thought this video was great! The supersonic wave shown in the photos and the history described is striking. I immediately bought the book Canary Girls of Chilwell.

Pouring Mercury into Liquid Nitrogen (slow motion)

Because sometimes you have to try things out!!!! The scientific method in action!

How much caffeine in coffee?

Because we are really addicted to caffeine and it’s my favourite molecule! I have extracted caffeine from coffee, yerba mate (from Argentina), tea and chocolate powder. A very good introductory organic chemistry experiment.

Nanoparticle Sign

I think this was my first gift to the Prof and to Periodic Videos back in 2011. I have fond memories of making it and a whole video dedicated to it was an unexpected pleasant surprise!

Peru Pictures

Recently back from a trip to Peru.

The trip started in Cusco, then followed the Salkantay trekking route to Machu Picchu.

I’ll have more information soon, including a podcast recorded during the trip.

But for now, here are some photos.

Belphegor's Prime and Harvey Dubner

For Halloween this year we released two videos about Belphegor’s Prime (on Numberphile).

If you’ve only seen part one, then part two is also well worth a look.

You may notice (in part one) that Tony Padilla makes mention of a “prime hunter” called Harvey Dubner.

Prior to publishing, I sent an email to Harvey because I wanted to include a picture of him in the video.

I received a reply… but unfortunately it arrived just after publication. The message came from Harvey’s son, Bob.

In a lovely email, Bob explained his father is now 90 years old.

He explained Harvey is in “pretty good” health, although suffering some memory problems and no longer does mathematics.

Bob, who was also instrumental in the prime number work, explained:

“I am, indeed, the designer of the “massive computer” we “built in the garage” – it actually was a series of software packages and special arithmetic hardware that I designed over the years between about 1981 and 2000.  They mostly sat next to the couch in the family room; Dad liked to have the TV on when he did mathematical research.

It was around the year 2000, when FFT routines  running on 400MHz and faster PCs overtook the hardware I had designed, that we gave up trying to improve my hardware.  By the year 2005, I had incorporated the GMP software package and the magically tweaked routines written by George Woltman (of the GIMPS project) into our software.  (I’m a pretty good programmer, but some of the people on the GMP project and Mr. Woltman are magicians.  And my long-time engineering motto has been, “We steal only the finest.”) 

We had a great run with the stuff I built; I believe that at our personal peak we had found about three-quarters of all the known prime numbers with more than 1,000 digits.  But by the early 2000s, not only were general-purpose computers faster than my hardware (which ten years earlier had given us supercomputer capability) but also lots of people started using publicly available software to search for big primes, purely for bragging rights.  So my father switched to looking for numbers he found interesting.  Many packages are optimized around calculating the primality of number of the form k * 2^N.  When k is one, you have the Mersenne primes, of course; but the calculations can run fast even for other values of k.  But my hardware and software was general purpose, so he looked for numbers that were interesting in base 10 – for example, the palindromic primes, of which the Belphegor Primes are a subset.  That was just for fun; he did a bunch of serious work in Sophie Germain Primes and Carmichael numbers.  But it was always fun searching for big primes of various kinds.”

Bob included a picture of Harvey, adding:

“He remembers that he used to do a lot of math, but he can’t remember the math at all.

He likes being reminded about it, though, and so I happily send along this picture, which I shot about a year ago.

Coincidentally, a friend just today pointed me at, which is, I believe, the episode in question, so I am probably too late with the picture.  But I figured I’d send it along anyway.

Thanks so much for your interest.  If you decide to edit in my dad’s picture, please let me know.  It would make him happy to see his image mentioned along with his work that way.”

So here’s the picture of Harvey - our thanks to him and to Bob.


Movies vs Books

The latest Numberphile video deals with the perennial question - does Hollywood ruin a book when they make it into a movie?

Hannah Fry takes a statistical look at the issue.

In the video we created a plot made with data compiled by Walter Hickey.


If you'd like to download a high resolution version so you dig down and see all the names, CLICK HERE (apologies for the overlapping... it was generated automatically for the video).

The extended interview with Hannah in the booth recording her audio book is on Numberphile 2.

And if you fancy the audio book, we encourage you to consider our show sponsor Audible.

Their 30-day trial includes a free audio book - and you could make it Hello World by Hannah Fry.

Visit or text numberphile to 500 500.

More Hannah books are here.