The mathematics of music means piano strings can never be in perfect harmony

Unlike with guitars and violins, pianos’ strings can never be perfectly tuned to one another. The solution? As this short animation from MinutePhysics explains, the instrument’s 88 strings across more than seven octaves means tuning a piano using harmonic intervals will inevitably lead to notes being fractionally off-pitch, with the issue compounding across octaves. So instead of using harmonics, piano-tuners generally keep octaves perfect, while leaving every other interval out of tune by just a tiny fraction. This workaround forsakes the appealing mathematical patterns of harmonics, but makes it possible to keep the kind of uniformity that is so valued in an era of mass production and reproduction of music.

Lockdown is a way of life for the US asylum-seekers living in churches

While much of the world was adjusting to lockdown and socialising via screens, life went on more or less the same for Vicky Chavez and her two young daughters. For more than two years, they have been unable to leave the First Unitarian Church of Salt Lake City in Utah, their makeshift home. After Chavez was ordered to deport to her native Honduras, which she fled to escape an abusive relationship, the church provided her refuge from US Immigration and Customs Enforcement (ICE) – which doesn’t pursue raids at places of worship – while her case is being fought in court. In her moving short Shelter in Place, the US director Kelsie Moore captures the family’s precarious life in limbo, which includes Chavez’s regular video calls with other asylum-seekers living in churches around the country.

Anil Seth on why our senses are fine-tuned for utility, not for ‘reality’

It’s easy to mistake our conscious experience for an ongoing, accurate account of reality. After all, the information we recover from our senses is, of course, the only window we’ll ever have into the outside world. And for most people most of the time, our perception certainly feels real. But the notion that our senses capture an objective external reality can be dispelled by considering something as fundamental as colour, which can be culturally influenced and, even within a single culture, leave the population split between seeing the same picture of a dress as black-and-blue or white-and-gold.

In this instalment from Aeon’s In Sight series, Anil Seth, professor of cognitive and computational neuroscience at the University of Sussex in the UK, puts our imperfect relationship with reality in perspective. In conversation with Nigel Warburton, consultant senior editor at Aeon+Psyche, Seth argues that it’s not just that our perceptions provide flawed accounts of the outside world, but that our brains aren’t in the business of recovering the outside world to begin with. So it’s more accurate to think of our conscious experience as a series of predictions that we’re incessantly and subconsciously fine-tuning – a world we build from the inside out, rather than the outside in.

For more from Anil Seth, read his Aeon essay on the ‘hard problem’ of consciousness.

Making dentures can be oddly riveting – a fusion of biology, craft and fun

‘Tooth after tooth: a brotherhood of pearly choppers! Upper and lower unite in a cuspidal embrace.’

Looking to pursue a career that combines science, craftsmanship and helping those in need? Then perhaps you might consider prosthodontics – the practical art of designing and fitting dental prosthetics. This playful British short from 1968 combines lab footage, stop-motion animation and a heavy dose of good humour to reveal how dentures are fashioned – a process that, we promise you, is far more fascinating than it sounds. And although the film is from the previous century, denture creation carries on today little changed, still requiring an expert human touch.

Can biofeedback help to unlock the mysteries of music’s therapeutic effects?

The US musician and research scientist Grace Leslie works at the frontiers of biotechnology and experimental music. From her Brain Music Lab at the Georgia Tech Center for Music Technology, Leslie and her students probe the physiological effects of sounds and rhythms, including how biofeedback could potentially be used to create new sonic therapies. Leslie’s lab work is inseparable from her unique original music, in which she synchronises instrumental performances with her own biorhythms and, in doing so, prompts her audience to synchronise with her. The result, she’s been told, are sounds akin to ‘a warm bathtub’. To hear more of Leslie’s work, watch the Aeon Video original Neurosymphony, which pairs an excerpt from her album Chapel (2018) with high-resolution MRI scans of a human brain.