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Michael Banks: August 2010 Archives

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Shot putters throw furthest at an angle of 37–38°

By Nicola Guttridge

Wimbledon? The World Cup? The Open Championship? Sport isn’t a great interest of mine, but despite my general ineptitude at most athletic activities, a recent paper caught my eye today in which two researchers studied the optimum angle of release in shotput – a problem that has baffled scientists since the 1970s. It’s not 45°, as you might expect. Instead, it turns out that athletes can throw a shot furthest when launched at a lower angle of about 37–38°. So why this difference in angle?

Alexander Lenz at the Technical University of Dortmund and Florian Rappl of the University of Regensburg in Germany puzzled over this and now believe that they have an explanation. It seems that the limitations aren’t in the mechanics but are to do with the human body. What it boils down to is that we humans are much better at pushing outwards than upwards, and so throwing the shot at a slightly lower angle than the expected 45° makes it travel further. To read more about this study, try the arXiv blog post.

As they point out, the human body’s preference for low angles of release is also apparent in weightlifting where weight records for bench pressing are much higher than for when the athlete tries to lift when standing.

Perhaps I should not have been surprised by the non-45° angle for shotputting. Back in 2006 scientists at the University of Brunel calculated the best angle to launch a football at during a throw-in and found it to be 30° to the horizontal – again, disagreeing with the expected angle of 45°. Most of these mistaken predicted angles can be explained by the theoretical calculations treating humans like perfect machines, a little reminiscent of superman – something that I’m sure many footballers would appreciate!

Another post I stumbled upon while reading around the shotput study was one about a completely different type of putting – golf. Robert Grober, an expert on the physics of golf at Yale University, has come up with a model to describe the perfect putt. Apparently the secret to golfing success lies in the behaviour of a simple pendulum being driven at twice its resonant frequency – I’m not sure how practical it’d be to attempt to use Grober’s model on a golf course, but even so it’s quite an interesting read. But then what do I know? I don’t like sport.

About the author
Nicola Guttridge is an intern with physicsworld.com

2053 Suns

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By Michael Banks

In 2003 the photographer Michael White compiled a book, 100 Suns, containing photographs of nuclear explosions drawn from the archives of Los Alamos National Laboratory in New Mexico and the US National Archives in Maryland.

The 100 images were taken in an era of “visible” nuclear testing before such tests went underground in the 1960s.

The images are fascinating, sometimes beautiful, but a chilling reminder of the power of such weapons. Indeed, today marks 65 years since around 100,000 people were killed by the nuclear bomb that was dropped on Hiroshima by a US B-2 bomber in 1945.

This morning I came across a video made by the Japanese artist Isao Hashimoto plotting nuclear weapons tests on a map of the world. As the years tick by from 1965 to 1998 a flash of light shows when a test occurred, where and by who.

The video by Hashimoto covers 2053 nuclear explosions that happened in the time period from the detonations at Hiroshima and Nagasaki in 1945 to the tests by India and Pakistan in 1998 – the period around the Cold War is a particularly active one.

2053 bombs over a 53-year period give an average nuclear detonation once every 9.5 days – a harrowing statistic indeed.

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Alcohol-induced superconductivity (Courtesy: Keita Deguchi)

By Michael Banks

When I was doing my PhD in condensed-matter physics, I remember seeing my colleagues nearly shedding tears after unsuccessfully spending months trying to make a single, small sample of a high-temperature superconductor.

The problem is that once a new superconductor – a material that exhibits zero electrical resistance when cooled below a certain temperature – is discovered then it takes only a few months before every conceivable experiment is performed on it. Time, as well as the quality of the sample, is everything.

So this morning I couldn’t help but raise a smile while skimming through the arXiv preprint server when I found a paper by researchers in Japan who have studied the effect of growing a new type of superconductor in “hot commercial alcohol drinks” such as red and white wine, beer, Japanese sake, whisky and shochu.

By heating powders of iron, tellurium and tellurium sulfide together at 600 °C they produced samples of FeTe0.8S0.2. But instead of performing experiments on these samples, they decided to put them into 20 ml glass bottles containing different alcoholic beverages.

They found that when they put the sample in an ethanol-water mixture, only around 10% of the material was superconducting below 6 K. But when it was dunked into whisky, sake or wine the superconducting fraction of the sample jumped. Red wine was found to be the highest with 63% of the sample exhibiting superconductivity. The researchers also saw a small increase in the superconducting temperature, with the red wine sample giving a superconducting temperature of 7.8 K.

Why this happens is unclear, but the researchers speculate that oxygen provided by the alcoholic drinks somehow gets into the bulk of the material and acts as a catalyst for the superconducting behaviour. The bigger question, though, is how the Japanese scientists got into the research in the first place. I haven’t asked but my guess is it originated after a trip to the local izakaya.

So can we expect other researchers to start dipping other samples into their favourite tipple? Maybe so – after all, back in 2008 scientists in Mexico grew small diamonds from tequila.

Whatever next?