5 posts tagged “physics”

A recent amazing series of computer simulations performed by a team of physicists from Russia, Germany and Australia reveals that dust clouds in space can harbour spiral structures capable of reproducing - and being selected - in the same way as terrestrial DNA. Read an Institute of Physics news article here, and read another brief article with useful links and discuss the implications at the Foundational Questions Institute (FQXi) community forum here.

The following image was lifted from the IOP article, but is presumably copyright the authors of the article which prompted the IOP news piece.

Spirals

A recent New Scientist news piece, "The universe is a string-net liquid", details how a new form of matter may have been predicted by refusing to accept the "fundamental" nature of basic particles. (Note that the strings in question have nothing to do with string theory, wonderfully summarised here.)

Blogs and blogging. If you weren't interested, you wouldn't be here.

Science and the communication of science. If you weren't interested, you wouldn't be here.

One of the most important discoveries of modern physics may be happening right now (these things take time), and the tantalising clues have been revealed in blogs. Read all about it.

(The Institute of Physics is getting all giggly about Web 2.0 and its potential impact on the way we do science. Read some of their free-online articles on the subject here.)

Physicsweb has a great little article about a peer-reviewed study showing how "[t]he rise and fall in the popularity of major religions can be described using the same mathematics that is used to model crystallization processes . . . The researchers have modelled the time evolution of the numbers of adherents to religions and claim that their work sheds light on an important social phenomenon – how a religion such as Christianity can grow rapidly from very small beginnings (Europhysics Letters to be published)."

Confronted with a novel problem at work or at home, the first thing that anyone from several generations of physicists, engineers, and applied mathematicians would do is reach for the nearest scrap of paper. On this, she will sketch a very rough model, an approximate set of equations, which describes the situation. She will then plug in estimates of the main quantities to obtain an answer which should be correct "to within an order of magnitude". By this she means that she has the right power of ten. Wikipedia's article calls this method "more than a guess but . . . less than a proof". Indeed, while a proof may require an accurate answer - such as 426.7 - a back of the envelope calculation will provide an answer like 300; correct to within an order of magnitude.

Writing in this month's Physics World (this article is not available online), Andrew Robinson recounts how from his teaching experience a new generation of scientists does not know how to make such reasoned estimates. Without a formula booklet to hand, and without being allowed their calculators, most of his university students apparently floundered until he sketched out the basics.

Skills like this are essential not only to scientists but to everyone who lives in a political democracy. Commitments to wars and refusal to confront climate change rest on voters' assessment of risk, for example, and especially the frequent ability to ignore massive risks such as getting in a car when considering much more minor risks. Making realistic reasoned estimates is vital.

On a lighter note, then, why not have a go at the following problem suggested by Robinson? How many pairs of shoes can be made from a single cow? The trick here is to make your model of a cow as simple as possible. Why not assume that the cow is box-shaped? Or a cylinder or even a sphere. Remember, it is an order of magnitude estimate we require, not a perfect answer. Please post your reasoned answers below.

Here's another which occurred to me on the way home: how much daily space should a British supermarket set aside for the storage of tea? (I use the example of tea and the UK because I grew up there drinking that, and so can make good estimates. If you would like to try coffee and American supermarkets, or any other example, please go ahead.)