Plus Blog

December 2, 2014

Have you recently taken up running in a bid to slow the inevitability of middle age? Or are you in the first glorious days of youth, feeling immortal and taking as many risks as you can? Or perhaps you've always taken the safe, and possibly unexciting, path? Whoever you are, you can find out just how dangerous a life you lead in The Norm Chronicles: Stories and numbers about danger by Michael Blastland and David Spiegelhalter.

David, our favourite statistician, has guided us through many a sticky statistical situation and has met many of his own making, including an excellent round on Winter Wipeout. He wrote a column here at Plus and is responsible for the excellent website Understanding Uncertainty, as well as many other activities. Michael, journalist, author and radio producer, is the person who first introduced us to the world of radio and podcasting. He created the fabulous BBC Radio 4 show More or Less.

You can find out more about how risky you are at the interactive website for Norm Chronicles and you can find out more about risk, statistics and probability here on Plus.

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December 1, 2014

There's not many things that have tempted us to leave our lovely job here at Plus and return to research, but reading Steven Strogatz's book Sync: the emerging science of spontaneous order was definitely one of them. It's a beautifully written book about the emergence of one of the most fascinating, and youngest, areas of maths: network science. Six degrees: The science of a connected age, by Duncan Watts, and Linked: How everything is connected to everything else and what it means for business, science and everyday life, by Albert-László Barabási, are equally brilliant accounts of the birth and early years of network science, all three written by researchers who played pivotal roles in founding this new area.

You can read more about the maths of networks on Plus, including the networks behind our brains, rapping, crime fighting and the best parties. And to find out how this all started, why not watch our oscar-worthy movie below!


You can read more about the bridges of Königsberg here.

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November 28, 2014

Our image of the week shows street art featuring the equation of the area of a circle.

Image © Andrew Hale and Patrick Cully.

The image was created by Andrew Hale and Patrick Cully, Research Engineers at Frazer-Nash Consultancy, studying for an EngD in the EPSRC Industrial Doctorate Centre in Systems, University of Bristol.

See here if you'd like to find out more about the area of a circle.

The picture is one of the images that appear in the book 50 visions of mathematics, which celebrates the 50th anniversary of the Institute of Mathematics and its Applications.

You can see previous images of the week here.

November 20, 2014

Our images of the week show the amazing snow art created by Simon Beck.

Koch snowflake

Snow art. Image © Simon Beck.

Koch snowflake

The Von Koch snowflake.

Koch snowflake

Simon Becks' book, Snow Art.

Beck creates those beautiful geometrical shapes by walking through the snow. The shape you see above is based on the Von Koch snowflake. To create the full shape, you start with an equilateral triangle and replace the middle third of each side by a "spike" consisting of two sides of a smaller equilateral triangle. Now do the same for each of the twelve straight-line segments of the resulting shape and repeat, ad infinitum. The Von Koch snowflake is an example of a fractal, a mathematical shape that is infinitely intricate and self-similar: it exhibits the same structures over and over again as you zoom in on smaller and smaller pieces. You can find out more about fractals here.

Beck can't produce the Von Koch snowflake exactly, of course, because it involves an infinite process. But he has created an amazingly good approximation, which comes from using the first few iterations of the process. He gets the shape down in the snow by counting steps to measure distances and using a compass when changing direction to make sure he gets the correct angles between straight-line segments. "In the case of the Koch shape, I found I was soon able to judge the 60 degree angles and do it quicker to an acceptable level of accuracy without using the compass," he says.

If you like the pictures, you can see more of them in Beck's new book, Snow Art, which you can purchase from his website. Here are a few more samples:

Koch snowflake

Image © Simon Beck.

Snow art

Image © Simon Beck.

Snow art

Image © Simon Beck.

Snow art

Image © Simon Beck.

You can see previous images of the week here.

November 19, 2014
A Hubble image

An image taken by the Hubble Space Telescope, courtesy NASA, ESA and E. Sabbi (ESA/STScI).

How important are experiments in science? Scientists use experiments to check whether a theory's predictions match up with reality, so without them you can't pick out bad theories.

In theoretical physics, however, there are many theories that cannot be tested. Not only because our experimental tools are nowhere near good enough, but also because there's some fundamental reason that stops us exploring some of the predictions those theories make. Examples are string theory, M theory and the various multiverse theories. Should we pursue them anyway, or dismiss them as speculation?

This debate, featuring one of our favourite theoretical physicists, David Tong (among others), explores this question and asks whether physics has strayed too far from experiment. It's been produced by the Institute of Art and Ideas in London.

1 comments
November 17, 2014

Our good friend Julian Gilbey has just told us about an amazing fact: if you roll a parabola along a straight line then the shape its focus traces out as it goes is ... a catenary! That's the shape a chain makes when it hangs freely under gravity and also the shape that gives you the strongest arches (see here and here to learn more).

Just why the two curves are connected in this way is a mystery (at least to us) — you can do the maths to prove it, but there doesn't seem an intuitive reason.

Julian has also produced this beautiful applet to illustrate the result. It shows the graph of the parabola with equation

  \[ f(x) = \frac{x^2}{4a} \]    

which has its focus at the point $F=(0,a).$ (Use the left-hand slider to change the value of $a.$) You can roll the parabola along using the right-hand slider and see the catenary the focus traces out. Its equation is

  \[ y = a\cosh {\frac{x}{a}.} \]    

Nice!

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