Category: ScienceNews

How do we know where a sound is coming from?

Another chance to hear this ear-opening episode, exploring a question from CrowdScience listener Chiletso. One day, he heard his son bounce a ball and instantly knew the direction it was travelling. How?

Anand Jagatia sets out to discover what makes left, right, up and down sound so different.

First, he gets blindfolded, so Alan Archer-Boyd, former auditory scientist and lead engineer at BBC R&D, can put his sound localisation skills to the test. It turns out that having two ears and pinnae, those flappy bits of cartilage on the side of your head, help a lot.

Professor Eric Knudsen shares how the barn owl’s asymmetrical ears allow it to hunt mice, even in complete darkness.

And Anand uncovers how far he can push his own spatial hearing. Blind activist and researcher Thomas Tajo teaches him how to echolocate like a bat, and Dr Lore Thaler explains what is going on in the brain of experienced echolocators.

This programme was originally broadcast in March 2023.

Presented by Anand Jagatia Produced by Florian Bohr for the BBC World Service

Image: Boy with hands at his ears Credit: Silke Woweries/Getty Images

Beyonce's new album tops the charts with a reappraisal of who can do country music and the Unexpected Elements team has a hoedown. Panellist Christine Yohannes unearths new research that changes our understanding of the origins of cowboys. Chhavi Sachdev has a thing or two to teach Beyonce as she reveals why the banjo has it's characteristic twang and we meet a man with powerful chemistry - TikTok dance sensation Dr Andre Isaacs from the College of the Holy Cross in Massachusetts tells presenter Marnie Chesterton how dancing in his lab helps explain click chemistry.

We also hear how new species could be given names that refer to the locations they're found in, we discuss whether mining is causing the Earth to shrink and, of course, eclipses make an appearance. We shed some light on how an eclipse over 100 years ago helped prove Einstein's theory of relativity.

Wednesday the Environmental Protection Agency announced new drinking water standards to limit people's exposure to some PFAS chemicals. For decades, PFAS have been used to waterproof and stain-proof a variety of consumer products. These "forever chemicals" in a host of products — everything from raincoats and the Teflon of nonstick pans to makeup to furniture and firefighting foam. Because PFAS take a very long time to break down, they can accumulate in humans and the environment. Now, a growing body of research is linking them to human health problems like serious illness, some cancers, lower fertility and liver damage. Science correspondent Pien Huang joins the show today to talk through this new EPA rule — what the threshold for safe levels of PFAS in tap water is, why the rule is happening now and how the federal standards will be implemented.

Read more of Pien's reporting on the EPA's first ever rule on PFAS in drinking water.

Want to hear more about health and human safety? Email us at shortwave@npr.org — we might cover your question on a future episode!

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The highly pathogenic strain of bird flu, H5N1, has arrived on the continent. Australian bird specialist Megan Dewar, from the Federation University of Australia, has led a mission aboard the research ship the Australis.

Science in Action remembers physicist Peter Higgs 60 years after his Nobel prize winning theory of the Higgs particle.

The unfolding scandal of manipulated data behind claims of incredible room-temperature superconductivity. Science writer Dan Garisto has seen the details in a Rochester University internal investigation.

And the alga – single-celled seaweed – with superpowers. As well as capturing carbon from CO2 in the atmosphere, like other plants, this one can directly capture nitrogen too, essential for life, but which few organisms can do for themselves. We hear from the marine scientist who has revealed this evolutionary trick.

Presenter: Roland Pease Producer: Jonathan Blackwell Production Coordinator: Jana Bennett-Holesworth

(Image: KAPPA-FLU team selecting skua carcasses for post-mortem examination. Credit: Ben Wallis)

It's National Siblings Day! To mark the occasion, guest host Selena Simmons-Duffin is exploring a detail very personal to her: How the number of older brothers a person has can influence their sexuality. Scientific research on sexuality has a dark history, with long-lasting harmful effects on queer communities. Much of the early research has also been debunked over time. But not this "fraternal birth order effect." The fact that a person's likelihood of being gay increases with each older brother has been found all over the world – from Turkey to North America, Brazil, the Netherlands and beyond. Today, Selena gets into all the details: What this effect is, how it's been studied and what it can (and can't) explain about sexuality.

Interested in reading more about the science surrounding some of our closest relatives? Check out more stories in NPR's series on The Science of Siblings.

Email us at shortwave@npr.org — we'd love to hear from you.

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It's baseball season! And when we here at Short Wave think of baseball, we naturally think of physics. To get the inside scoop on the physics of baseball, like how to hit a home run, we talk to Frederic Bertley, CEO and President of the Center of Science and Industry, a science museum in Columbus, Ohio. He also talks to host Regina G. Barber about how climate change is affecting the game.

Interested in the science of other sports? Email us at shortwave@npr.org — we'd love to hear from you.

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Today there are over eight billion people on Earth. That’s an awe-inspiring figure… but how does it compare to the vast numbers who came before us? Listener Alpha wants to know how many people have ever existed, so CrowdScience sets out to do a historical headcount.

The Population Reference Bureau in the USA estimated this number back in the 90s, and have been updating their calculations ever since. Demographer Toshiko Kaneda explains how their model works, the assumptions it makes – and the huge uncertainties around the number it comes out with.

We first need a date for when ‘humans’ first began, so Caroline travels to the Natural History Museum in London to meet human evolution expert Chris Stringer, and marvel at his collection of replica fossil skulls. Chris demonstrates how to distinguish our species, Homo sapiens, from other species like Neanderthals. When did these species first appear - and which of them count as human?

And once you know where to start the clock, how do you estimate the numbers of people alive at different points in history? For a population demographer like Walter Scheidel, it helps that some ancient civilisations kept detailed censuses, a few of which have survived to the present day. Caroline and Walter pour over one of these census fragments, and learn how to combine them with other archaeological clues to get some very rough numbers.

And finally: what does the future of our population look like? Poonam Muttreja from the Population Foundation of India discusses developments in the world’s most populous country, as well as the big demographic trends ahead for humanity.

Presenter: Caroline Steel Producer: Phil Sansom Additional Recording: Umaru Fofana Editor: Cathy Edwards Production Co-ordinator: Connor Morgans Studio Manager: Sue Maillot

Featuring: Toshiko Kaneda, Technical Director of Demographic Research, Population Reference Bureau Chris Stringer, Research Leader in Human Evolution, Natural History Museum London Walter Scheidel, Professor of Classics and History, Stanford University Poonam Muttreja, Executive Director, Population Foundation of India

In a year when billions of people have been to the ballot box, what do stickleback fish have to do with it? Alex Lathbridge, Tristan Ahtone and Candice Bailey discuss some unexpected elements of electoral studies.

Can ancient geology really map election outcomes? What has machine learning done for polling? Psychologist Sandra Obradović drops in to share some of her expertise in the psychology of voting with the team.

Plus, what does a solar eclipse have to do with dragons?

Presenter: Alex Lathbridge, with Tristan Ahtone and Candice Bailey Producer: Katie Tomsett, with Harrison Lewis, Alex Mansfield and Phil Sansom

Tiny, black-capped chickadees have big memories. They stash food in hundreds to thousands of locations in the wild – and then come back to these stashes when other food sources are low. Now, researchers at Columbia University's Zuckerman Institute think neural activity that works like a barcode may be to thank for this impressive feat — and that it might be a clue for how memories work across species.

Curious about other animal behavior mysteries? Email us at shortwave@npr.org.

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A powerful earthquake hit Taiwan on Wednesday morning, but thanks to the country’s early warning system and engineering-preparedness, there was little destruction and few deaths. Seismologist Ross Stein, CEO of earthquake consultancy Temblor, Inc., shares his analysis. The highly pathogenic bird flu H5N1 has been detected in cattle in the US and in a cattle handler in Texas. To learn more about this special animal-to-human transmission, Roland speaks to virologist Richard Webby of St. Jude Children’s Research Hospital in Tennessee and Director of the World Health Organization Collaborating Center for Studies on the Ecology of Influenza in Animals. French Space Institute Supaero in Toulouse is collaborating with Japan’s space agency JAXA to send and land a rover on Phobos, one of Mars’ tiny moons. Roland travels to the University of Toulouse to learn more about building this wheeled Rover from Supaero’s Naomi Murdoch.

Transitioning to a clean energy future requires mining materials like rare earth minerals, but how will this impact our environment? Jessi Junker of the ecology charity ReWild explains her research and concerns for great apes as mining for these materials expands in Africa.

Presenter: Roland Pease Producers: Roland Pease, Ella Hubber, Jonathan Blackwell Researcher: Imaan Moin Production Coordinator: Jana Bennett-Holesworth

(Photo: Damaged building caused by the earthquake in Hualien on April 4, 2024. Credit: SAM YEH/AFP via Getty Images)