Tag archives: history of physics
By Hamish Johnston
“The death of the astronomical second and the birth of atomic time” is how the British physicist Louis Essen described 3 June 1955, when the world’s first practical atomic clock ticked for the first time.
The place was Teddington on the outskirts of London, which is home to the National Physical Laboratory (NPL). Essen’s clock was based on a beam of caesium atoms and was monitored by microwave technology inspired by his wartime work on radar. The clock was more than a metre long and nicknamed the “Flying Bedstead” by engineers at the BBC, who used it as an input for their radio time signal. The clock made atomic time available worldwide for the first time 60 years ago. Then, in 1967, the second was redefined as an SI unit based on an atomic transition in caesium, thereby ending the ancient practice of defining time though astronomical observations.
By Matin Durrani
Like all good publications, Prospect has a strapline about itself – “the leading magazine of ideas”. Physics World is also about ideas, although sadly our magazine, great though it is, doesn’t have adverts for Cartier watches, Embraer executive jets or the Taj Exotica Resort & Spa in the Maldives as Prospect does. Clearly, some people with ideas have more money to spend than others.
I was kindly invited last week by the deputy editor of Prospect, Jay Elwes, to an event he hosted at the magazine’s headquarters in central London. The event featured the University of Oxford physicist Frank Close, who has just published a new book on the life and times of Bruno Pontecorvo. Close was on hand to discuss the key themes of the book, which is entitled Half Life: the Divided Life of Bruno Pontecorvo. Elwes described the attendees as a “small, high-powered group”, including as it did Pauline Neville Jones, the former chair of the UK’s Joint Intelligence Committee and Jonathan Evans, the former director-general of the British security service MI5.
By Tushna Commissariat
This Sunday, as the world celebrates International Women’s Day, I’ll be thinking of some amazing women who had a huge impact on the world of physics, helping shape the field as we know it today. Indeed, yesterday I was at the Institute of Physics in London, attending a day-long conference on “The lives and times of pioneering women in physics” hosted by the Institute’s Women in Physics group along with its History of Physics group. While there were a host of interesting speakers at the event, undoubtedly the star of the day was French nuclear physicist Hélène Langevin-Joliot, granddaughter of one of the 20th-century’s most famous female physicists – Marie Curie.
By Tushna Commissariat
There is nothing quite like a bowl of hot, buttery popcorn – and it seems as if even physicists are enthralled by it as they dig into the pops and jumps of this tasty snack. A recent article in the New York Times caught our attention this week, as it talked about how a French research duo used high-speed video cameras and a hot plate to see just why a kernel of corn not only pops, but also leaps up as it puffs. The team found that as the kernel’s hull is breached, we hear the popping sound and this is swiftly followed by the jump that happens when a puffy bit of the inside pushes out and makes the corn jump, a bit like a muscle twitch. Take a look at the lovely slow-motion video above of individual kernels leaping about like perfect puffy ballet dancers.
By Hamish Johnston
Fancy a Hubble Space Telescope T-shirt or perhaps a pair of leggings printed with glow-in-the-dark stars and planets? For pictures and links to these and other stellar fashions, check out the STARtorialist blog, which is run by two astronomers based in New York City and described as “Where science meets fashion and scientists get fabulous!”.
By Matin Durrani in Paris
It was a grey and dank morning yesterday in the French capital, with even the top of the Eiffel Tower shrouded in clouds – perhaps not the most auspicious weather for the official opening ceremony of the International Year of Light and Light-based Technologies (IYL 2015) here at the headquarters of the UN Educational, Scientific and Cultural Organization (UNESCO).
Inside the conference hall, however, all was brightly lit. The stage was bathed in beams of light in all the colours of the rainbow as the 1500 or so delegates first watched an official IYL 2015 video and then listened as a series of dignitaries voiced their backing for the initiative.
These included a message of support from UN director-general Ban Ki-moon read out by an official and a video recording from Irina Bokova, UNESCO director-general. There were also speakers from Ghana, Mexico, New Zealand, Russia and Saudi Arabia – the five nations that took a key role in getting IYL 2015 approved by the UN in late 2013.
By Tushna Commissariat
The results of a successful scientific experiment can make scientists very happy. Indeed, in the clip above, taken from the BBC TV series Human Universe, one scientist exclaims “holy mackarel!” when he sees the outcome he was hoping for. In the video, everybody’s favourite physicist Brian Cox carries out an experiment similar to Galileo’s Leaning Tower of Pisa experiment, where he tested that no matter the mass of objects, they fall at the same rate under gravity. In the video above, Cox drops a bunch of feathers and a bowling ball in the world’s biggest vacuum chamber – the Space Simulation Vacuum Chamber at NASA’s Space Power Facility in Ohio, US. In the slow-motion video, you can see with exquisite clarity just how accurate Galileo’s prediction was, as the feathers and ball land at precisely the same time. We came across this video on the Dot Physics blog on the Wired Science network, written by physicist Rhett Allain, where he has worked out some of the maths and pointed out some of the nuances of the above experiment, so make sure you take a look.
By James Dacey in Córdoba, Argentina
What’s the best way to teach tricky physics concepts to students? Naturally, this was one of the questions underpinning many of the talks here at the International Conference of Physics Education (IPCE) in Córdoba. According to a couple of educationalists in Latin America at least, it seems that one approach is to enlist the help of some of the great scientists and philosophers of the past.
Patricia del V. Repossi, a lecturer at the Pontificia Universidad Católica Argentina in Buenos Aires, spoke about how she uses the history of science as a framework for teaching optics. Repossi explained how she had come to realize that some of the students taking her conventional optics course believed that photons are made of the same stuff as “tennis balls”. So, she and her colleagues set about transforming the way they teach the topic – by combining a physics class with a history lesson.
By Hamish Johnston
“How we created spooky experimental music in a superconductor lab”: what physicist could resist clicking on this story, which appeared on the Guardian website earlier this week? Written by the physicist-turned-computational-biologist Andrew Steele, the article describes how Steele and a few pals converted a magnetic sensor into a musical instrument. Like the theremin, which is played by waving your hands around an antenna, this new instrument responds to the player’s motion. But because the sensor was optimized for studying superconductors rather than creating freaky mood music, Steele explains the “instrument covered three octaves in less than a centimetre of hand movement”. He suggests that playing the instrument should probably be left to a talented gerbil rather than talented superconductor researchers. You can listen to Steele’s attempt at making music on SoundCloud.
By Margaret Harris
Last Sunday I went up to Cheltenham for the final day of the town’s annual Science Festival. My plan was to meet the University of Maryland theorist Jim Gates before lunch and then stay to hear his lecture on science and policy.
I was already somewhat familiar with Gates’ research thanks to a feature he wrote for Physics World in June 2010. I could also have made an educated guess about his activities as a member of the President’s Council of Advisers on Science and Technology (PCAST). However, I knew very little about his personal history before his evening lecture, when he was interviewed by the physicist and science presenter Jim Al-Khalili.
Gates was born in 1950 and grew up during a period when African-Americans faced severe institutionalized discrimination across the US. However, being from a military family helped insulate him from some of the worst effects, and he told the audience that he didn’t feel the full impact until his family moved to Florida after he turned 11. For the first time, he attended a racially segregated school, and there, he said, he had “the very curious experience of having to learn how to be black”.