Issue 44

September 2007
What's the risk of climate change or passive smoking? Why do penguins rotate their eggs? What makes mathematicians reach out for god? And how did we evolve the maths behind these questions? Find some answers in this political, psychological, philosophical and physical issue of Plus, and do some real sums with our interactive checker board.
Phil Wilson continues our series on the life and work of Leonhard Euler, who would have turned 300 this year. This article looks at the calculus of variations and a mysterious law of nature that has caused some scientists to reach out for god.
What's the risk of passive smoking? Or climate change? How big is the terrorist threat? And should we trust league tables? These issues concern all of us, but it's not always easy to make sense of the barrage of media information. David Spiegelhalter, Winton Professor for the Public Understanding of Risk, gives Plus his take on uncertainty.
How did we evolve our capacity for maths? Does maths piggy-back on our ability for language, or is it a completely separate faculty? Is it dependent on culture? Plus spoke to the cognitive psychologist Rosemary Varley to find some answers.
John Napier was a clever man indeed. Besides inventing the logarithm, he developed ingenious calculating devices that fully exploit the power of the positional system. In this article Chris Sangwin tells you how to make your own set of Napier's bones and perform mathemagic with an interactive checker board.
Former Plus editor Helen Joyce explains how Plus made it big as a part of our series to celebrate Plus's tenth anniversary.
How does complexity arise from simplicity?

Plus 1000 — Mathematical lives

Penguin eggs are not something you'd normally associate with maths, but they are right there on the archives of the Smith Institute, an organisation helping businesses use maths to solve their problems. Claudia Centazzo tells us about her role at the institute, selling maths to unsuspecting business people.
The flocking behaviour of birds, the spread of diseases and the Cuban missile crisis — all of these and much more can be modelled mathematically. In our second teacher package we bring together all Plus articles on mathematical modelling, ready for use in classroom discussions or students projects.
Greater than sudoku!
The movie is based on one of the best mathematical tales ever written. Inhabiting a two-dimensional world populated by polygons and ruled by circular tyrants, a bright young hexagon, through sheer mathematical willpower, imagines a third dimension.
Given that 14 billion years have elapsed since the birth of the Universe and that the cosmos contains a mind-boggling 1024 stars, can Earth really be the only planet in the entire Universe to contain life?
Imagine that on your first day training to be a builder you are given a set of toy blocks with which to build a model house.
A review of a book as good as this must either repeat the positive adjectives other reviewers have used, or require a very large thesaurus.