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Alexander Bogomolny, creator of Cut the Knot, has died.

Alexander Bogomolny was a mathematician and educator well known for his website Cut the Knot, which offered interactive mathematical miscellany and puzzles. You can learn more about him, education and antisemitism in the USSR, his mathematics research and his approach to Cut the Knot in this interview from 2014.

Are there More or Less stars than grains of beach sand?

This week’s episode of More or Less on the BBC World Service answered a question that involved estimating big numbers: Are there more stars than grains of beach sand?

This claim was famously made by Carl Sagan in the seminal programme Cosmos.

The cosmos is rich beyond measure. The number of stars in the universe is larger than all the grains of sand on all the beaches of the planet Earth.

More or Less come to a fairly standard answer, that Sagan was correct. This sort of problem, which involves approximating unknowable numbers based on a series of estimates, is called a Fermi problem. I’ve written about Fermi problems here before. The More or Less approach to answering this raised a question from a reader of this blog.

Alright, actually Paul is one of the writers of this blog, rather than a reader. Even so, are his concerns warranted?

My cat isn’t psychic – but your pet could be!

Do you remember Paul the Octopus? During the 2010 World Cup, in what his Wikipedia page calls “divinations”, Paul was offered boxes of food labelled with different competitors. Whichever box he ate from first was considered his prediction for the match, with some success.

Yesterday morning, my son and I did something similar with our cat, Tabby. This is in response to Matt Parker’s latest initiative, Psychic Pets. Matt is hoping to get thousands of pet owners to make predictions, in order that the odds are good a pet can be found which predicted all prior results for both teams in the final. The good news is it’s fairly straightforward to take part.

Approaching Fermi problems with the approximate geometric mean

I gave a talk on Fermi problems and a method for approaching them using the approximate geometric mean at the Maths Jam gathering in 2017. This post is a write up of that talk with some extras added in from useful discussion afterwards.

Man talking on the phone

Enrico Fermi apparently had a knack for making rough estimates with very little data. Fermi problems are problems which ask for estimations for which very little data is available. Some standard Fermi problems:

  • How many piano tuners are there in New York City?
  • How many hairs are there on a bear?
  • How many miles does a person walk in a lifetime?
  • How many people in the world are talking on their mobile phones right now?

Hopefully you get the idea. These are problems for which little data is available, but for which intelligent guesses can be made. I have used problems of this type with students as an exercise in estimation and making assumptions. Inspired by a tweet from Alison Kiddle, I have set these up as a comparison of which is bigger from two unknowable things. Are there more cats in Sheffield or train carriages passing through Sheffield station every day? That sort of thing.

Ten years and eight days

On 31st January 2008, I gave my first lecture. I was passing my PhD supervisor in the corridor and he said “there might be some teaching going if you fancy it, go and talk to Mike”. And that, as innocuous as it sounds, was the spark that lit the flame. I strongly disliked public speaking, having hardly done it (not having had much chance to practice in my education to date – I may have only given one talk in front of people to that point, as part of the assessment of my MSc dissertation), but I recognised that this was something I needed to get over. I had just started working for the IMA, where my job was to travel the country giving talks to undergraduate audiences, and I realised that signing up to a regular lecture slot would get me some much-needed experience. I enjoyed teaching so much that I have pursued it since.

I just noticed that last Wednesday was ten years since that lecture. It was basic maths for forensic science students. I was given a booklet of notes and told to either use it or write my own (I used it), had a short chat about how the module might work with another lecturer, and there I was in front of the students. That was spring in the academic year 2007/8 and this is the 21st teaching semester since then. This one is the 15th semester during which I have taught — the last 12 in a row, during which I got a full-time contract and ended ten years of part-time working.

I have this awful feeling this might lead people to imagine I’m one of the people who knows what they are doing.

P.S. The other thing that I started when I started working for the IMA was blogging – yesterday marks ten years since my first post. So this post represents the start of my second ten years of blogging.

Particularly mathematical New Years Honours 2018

When the UK Government announces a new list of honours, we (let’s be honest – sometimes) write up a list of those particularly mathematical entries. Here is the selection for the 2018 New Years Honours list.

  • Howard Groves, Member, Senior Mathematical Challenge Problems Group and Member, UK Mathematics Trust Challenges Sub Trust. OBE, for services to Education.
  • Christl Donnelly FRS, Professor of Statistical Epidemiology, Imperial College London. CBE, for services to Epidemiology and the Control of Infectious Diseases.
  • Ben Goldacre, Senior Clinical Research Fellow, Centre for Evidence-Based Medicine, University of Oxford and author of Bad Science. MBE, for services to Evidence in Policy.
  • Andrew Morris, Professor of Medicine, Director of the Usher Institute of Population Health Sciences and Informatics, and Vice-Principal Data Science, University of Edinburgh. CBE, for services to Science in Scotland.
  • Stephen Sparks, lately Professorial Research Fellow, University of Bristol and former chair of ACME. Knighthood, for services to Volcanology and Geology. (Via The Mathematical Association.)
  • Bernard Silverman, lately Chief Scientific Adviser, Home Office and former President of the Royal Statistical Society (RSS). Knighthood, for public service and services to Science. (Via Hetan Shah.)
  • John Curtice, Professor of Politics, University of Strathclyde and Senior Research Fellow, NatCen Social Research, and Honorary Fellow, RSS. Knighthood, for services to the Social Sciences and Politics. (Via Hetan Shah.)
  • Diane Coyle, Professor of Economics, University of Manchester. CBE, for services to Economics and the Public Understanding of Economics. (Via Hetan Shah.)

Get the full list here. If you spot any others we should mention, please let us know in the comments.