From wine and skis to clocks and bone implants, Linn Hobbs has a passion for everyday materials, as he tells Robert P Crease
If you want to get a sense of the power and beauty of materials science, there are few better places to start than a chat with Linn Hobbs. Living in retirement in a three-storey house on the outskirts of Boston, US, Hobbs spent most of his career at the nearby Massachusetts Institute of Technology and retains an almost child-like enthusiasm for materials science. “[It] explores the kinds of things you can find in an average 10-year-old’s pocket,” he claims. “Salt, sand, string, rust and bone.”
Born in 1944 in Detroit, Hobbs’ interest in science started early. He was a licensed ham-radio operator at 11, later built his own communications equipment and these days still broadcasts from the top floor of his house. In 1962 Hobbs went to study engineering science at Northwestern University in Illinois, where the first book he read was on metals. “I was astounded that so much science could be applied to so much of the world around us,” he told me when I visited last summer. “I read the book like a novel, cover to cover in three days.”
Hobbs tried to major in materials science, but was informed that Northwestern had no major in the subject. All it had was a graduate materials-science department, which had been set up by the Advanced Research Projects Agency (ARPA) just two years earlier. ARPA itself had been established as a panic measure by the US government, which realized it lagged the Soviet Union in missile technology following the launch of Sputnik – the world’s first artificial satellite – in 1957. ARPA was designed to foster the study of metal alloys, ceramics and other compounds that could withstand the extreme pressures and temperatures of missiles and spacecraft.
When Hobbs arrived at Northwestern, even the university’s grad students in materials science had little prior training in the new discipline.
So when Hobbs arrived at Northwestern, even the university’s grad students in materials science had little prior training in the new discipline. Undeterred, Hobbs learned alongside them, despite his status as a lowly undergraduate. With his electronics experience as a radio operator, he ended up building equipment to study the motion of dislocation defects in lithium fluoride, which has a crystal structure identical to that of table salt.
After graduating from Northwestern in 1966, Hobbs went to the UK on a Marshall Scholarship, winding up at the University of Oxford, which then was a world-leader in the electron microscopy of materials. Hobbs’ subsequent career leant heavily on this tool, using it in a constantly widening set of applications that were turning materials science into an ever more unified field.
Hobbs’ hobbies
During his decade at Oxford, Hobbs took up a series of life-long hobbies, each involving different facets of materials science and reflecting a growing fascination with historical artefacts.
One hobby was antiquarian horology, instigated by his purchase of an old clock in an Oxfam charity shop for £10. On my visit to his house, our conversation was periodically punctuated by bright, high-timbre chimes from many of his subsequently acquired clocks. Hobbs explained the role of various clock materials – wood, iron, steel, brass, bell-metal, even sapphire – and discussed how they drove the history of these devices. Material behaviour was also critical for the forte pianos (an early kind of piano) in Hobbs’ collection of these instruments.
At Oxford, Hobbs became the wine steward at Wolfson College. This was a prestigious gig: Oxbridge colleges take their wine very seriously and Hobbs now owns a 2500-bottle wine cellar. As he showed me round it, Hobbs stopped to explain the structure of Champagne bottles; the indent at the bottom, called a punt, is mechanical reinforcement. He also explained the different colours of glass bottles – their silicate glass deriving from sand – with green being so common as the iron impurities causing it are the hardest to remove. A stack of skis next to the wine cellar then led Hobbs to explain why his knowledge of their component materials saw him becoming a consultant for a ski company.
Linn Hobbs is keenly aware just how integral materials science is to different fields of research.
Hobbs is keenly aware just how integral materials science is to different fields of research. He told me how he once listened to a young biologist describing difficulties with in vitro studies of cellular processes in bone formation. These studies were being carried out in Petri dishes, prompting Hobbs to enquire as to the nature of the glass substrate. Looking at him blankly, the biologist exclaimed in frustration: “Glass is glass!” Hobbs replied, “No, it’s not,” and explained that there are many types of glass, whose composition, surface chemistry, topography and defects all affect biological processes.
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During his career, Hobbs has also studied the materials science of natural polymer fibres used by ancient cultures – the “string” in the child’s pocket – as well as metal corrosion processes, such as the rusting of iron. As for bone, Hobbs and his research group used electron microscopes to study bone biomineralization processes. In collaboration with the Royal National Orthopaedic Hospital in London, he also examined how bone bonds to orthopaedic implants, discovering that bone mineralization can begin after just three days.
The critical point
Few American materials scientists, it is safe to say, have been awarded an OBE (Order of the British Empire), which Hobbs received for his long involvement with the Marshall Scholarship programme and other Anglo-American educational initiatives. As for our conversation, it left me with an appreciation for two aspects of the history of materials science. One is that it is driven by society’s demands for better materials in everything from housing, clothing and transport to defence, art and medicine. The other is the role of scientific instruments in advancing our understanding of materials. This has simultaneously extended materials science into previously separate fields – notably metallurgy, ceramics and glass, polymers, biology and medicine – and unified much scientific research in these varied disciplines.
