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  1. Art for art’s sake

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    In response to Paul Axelrod’s Forum article “Why the arts matter” (January 2018) in which he warns against the dangers of ignoring the arts and the social sciences, in favour of only promoting STEM subjects.


    Axelrod makes many very interesting and valid points that deserve to be widely discussed and debated. An important implication that he failed to observe though, is that university students who complete a STEM programme without being required to take any courses in the humanities and social sciences have not received a complete educational experience; something which should not be allowed to happen at any institution. Universities should produce well-balanced graduates who are not only competent in their major field of study, but are also familiar with other areas of intellectual inquiry.

    Universities should produce well-balanced graduates who are also familiar with other areas of intellectual inquiry

    Institutions involved in only STEM programmes at all levels are easier for governments to create and control. For example, China has superb pure and applied science institutions of advanced study which are, in reality, part of the civil service for a totalitarian government. It is only in democracies where independent institutions exist, with strong programmes in the humanities, arts and sciences, and government policies and their alternatives can be freely evaluated, studied and debated free from political interference.

    Graduates should be capable of recognizing and analysing current social, economic and technical problems and changes and relating them to what has occurred in the past and be motivated to play an active role in society.

    Harvey A Buckmaster

    Victoria, BC, Canada

  2. Climate hop

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    In response to Jennifer Ouellette’s feature “When cold warms faster than hot” (December 2017) in which she describes what could be a new theoretical understanding for the so-called Mpemba effect – and why it predicts that cold water could even heat up faster than warm water.


    Some years ago, one of my ablest students investigated the Mpemba effect for his extended essay, as part of his International Baccalaureate Diploma. Consistent with others, the results of his excellent investigation were inconclusive. Convection-induced supercooling looked the most convincing mechanism at the time. He performed his experiment in a domestic refrigerator and I did wonder whether supercooling might have been thwarted whenever the thermostatically-controlled pump switched on or off, with freezing induced by the vibration.

    With my interest piqued, I found the excellent article by Ouellette so absorbing that I chased down all the papers referenced. The paper by Zhiyue Lu and Oren Raz on the Markovian Mpemba effect brought to mind my undergraduate project when I used an electronic circuit to investigate whether stochastic resonance might be responsible for the glacial-interglacial hopping of our climate throughout the present Pleistocene ice age. Our climate was modelled as having two stable states, with a ‘particle’ sitting in a symmetric double-well or ‘Mexican hat’ potential. Changes in our orbit (eccentricity, obliquity, precession) described by the Milankovitch Effect was modelled as a sinusoidal forcing of the potential, which made it see-saw about the potential barrier, but nowhere near enough to induce the particle to hop. But the introduction of some Gaussian white noise over a narrow range of power spectral density made the particle (the climate) hop in a periodic way, leading to the counter-intuitive observation that the signal (periodic hopping) increased in response to an increase in noise. Since I left research for teaching two decades ago, accessible feature articles in Physics World are a very welcome way of keeping abreast of developments.

    Mike Follows

    Acting head of physics, King Edward’s School, Birmingham, UK

  3. Flipping physics

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    In response to a Quanta story “Water-flipping physics” (February 2018) about the viral Internet craze of flipping a bottle of water until it lands upright.


    New balls please Tennis balls in bottles may be used in the classroom to demonstrate flipping physics (Shutterstock /Passakorn sakulphan)

    Being the coach of a junior football club, I am only too aware of the water-bottle flipping phenomenon, which, at least in Derbyshire, shows no sign of abating. What intrigued me most from your article was the suggestion from Netherlands researchers that a classroom demonstration could be carried out using two tennis balls inside the bottle. How, pray, does one get two tennis balls inside a bottle? Quantum tunnelling?

    Simon Edwards

    Idom Merebrook, Derbyshire, UK

    The editor responds:

    A good question Simon! I looked up the paper (arXiv:1712.08271) and the researchers use what they call a “tennis bottle”, which is a cylindrical bottle without a neck.

  4. More on midges

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    In response to Jennifer Ouellette’s feature “Sounding out swarms” (February 2018) in which she looks into swarming midges and the unusual characteristics of their collective behaviour.


    Congratulations on a really accessible, fun-to-read, balanced article. I found the feature fascinating, but it’s a pity you did not have room to mention my work on the modelling of Nicholas Ouellette’s swarms, which was recently published in the Journal of the Royal Society Interface. Nicholas emphasized that models must now be able to capture both the intricate dynamics of swarms and the emergent “material”’ properties of swarms. My model predicts many of Nicholas’ intriguing observations, including the emergence of solid-like mechanical properties and the co-existence of core condensed phases surrounded by dilute vapour phases. And it may account for the stark differences in swarming behaviours observed in the stillness of the laboratory and under natural conditions.

    The strong correlations seen outdoors may help swarms resist environmental disturbances. Intriguing connections have also made with self-gravitating systems like clusters of stars and with Gerber’s long-forgotten theory of speed-dependent gravity. This all stems from the simplest of model ingredients, the swarm’s aerial density profile and its velocity statistics.

    Andy Reynolds

    Rothamsted Research, Harpenden, UK