CrowdScience

They probe whether AI could take over presenting by cloning voices and simulating interviews. Experts explain how large language models are trained and how AI performance is measured. Researchers demonstrate why synthetic speech still sounds slightly off and why many languages lag behind. The BBC’s experiments and ethical rules about using AI for content are also discussed.

CrowdScience listener Doug has been experimenting with holding his wireless garage key to his chin. Why? Because he's testing a strange trick of physics. The range of a key can apparently double when held against your head rather just being held in your hand. Could this really be true, and if so why? Presenter Caroline Steel goes on a wavy journey of self-experimentation with antennas. She follows the story of Doug as he wanders the streets of Calgary in Alberta, Canada testing the key on his head from different distances and even testing it on his dog Maura’s head. To understand the physics behind all this, Caroline meets Dr Lina Mohjazi, Lecturer of Autonomous Systems and Connectivity at the University of Glasgow and Guy Vandenbosch, Professor of Electromagnetic Radiation at KU Leuven University in Leuven, Belgium. Presenter: Caroline Steel Producer: Tom Bonnett Editor: Ben Motley(Photo: Hand holding a car key remote in front of a red car - stock photo Credit: vadishzainer via Getty Images)

Gabriele Oettingen, psychology professor who developed the WHOOP mental-contrasting method. Sabina Brennan, neuroscientist and psychologist focused on attention and behaviour. Lucas Dixon, researcher who measured belief in manifesting and its links to risk. They discuss what manifesting means, how focused attention and gratitude can steer behavior, why positive fantasies can sap energy, and a practical mental-contrasting technique.

CrowdScience listener Ndanusa in Ghana, is gazing up at the stars, and wondering. Big philosophical questions, like… what keeps our universe in balance? From our perspective here on earth, the universe seems like a vast, harmonious system, perpetuating eternally without change. But Ndanusa knows a thing or two about the stars, and he knows that they use up hydrogen as they burn, and release helium. And he’s wondering, is there something out there which does the opposite? Something that uses up helium, and produces hydrogen, to keep the universe in perfect, chemical equilibrium? His question makes sense! Here on earth for example, animals use up oxygen and produce carbon dioxide, and plants do the opposite. A perfect cycle of production and consumption which (at least in theory), keeps our planet in perfect balance. Could the same kind of system be in place in the wider expanse of the universe? His intriguing question leads presenter Alex Lathbridge on a journey into the blackness of deep space, the ancient origins of our universe, and the complex physics of the stars. He pops into the Ghana Radio Astronomy Observatory, just outside Accra, where astrophysicist Dr Proven Adzri helps him peer into the earliest few seconds of our universe, and find out what set the stars burning. And at Kwame Nkrumah University of Science and Technology, Dr Linus Labik talks him through what’s going on at the atomic level. And in the deep blackness of the night, up above the tree canopy of Kakum National Park, he takes a peek at the stars for himself. Local guides Chris and Kwabena explain how much meaning there is behind the stars in the night sky. Presenter: Alex Lathbridge Producer: Emily Knight Editor: Ben Motley (Photo: Large orange and purple exploding orb - stock photo Credit: Soubrette via Getty Images)

Australia’s Great Barrier Reef is one of the richest and most complex natural ecosystems on earth, and it’s home to over 600 species of coral – marine animals that are most closely related to jellyfish. But the coral is under threat, with climate change, ocean acidification and marine heatwaves endangering the reef and the many iconic animals that depend on it. CrowdScience listener Felix, aged 9, wants to know what we’re doing to protect it, and presenter Caroline Steel is on the case. In this special edition of CrowdScience, we follow scientists from Australia’s Institute of Marine Science as they attempt to restore the reef with baby corals that they’ve nurtured in experimental tanks at their Sea Simulator facility on the country’s northeast coast. This experiment kicked off in December, as the researchers recreated the annual mass coral spawning event in controlled conditions, manipulating temperature, pH, light, and nutrients to breed coral baby that they can then use to reseed damaged sections of reef. After loading up a lorry full of corals and waving it goodbye, Caroline heads north for a rendezvous at dawn, as the corals are loaded onto a boat in Cairns. She travels across the coral sea with marine biologists from AIMS, and is on hand as the corals are introduced to their new home in the ocean. This is just the beginning - a proof of principle. In future years, the scientists are hoping to reseed heat-tolerant corals, and to scale up and automate this work. But even then, is the scale of the problem too big? Can we restore a reef area the size of Japan, or is it too late? Presenter: Caroline Steel Producer: Marnie Chesterton Editor: Ben Motley (Photo: Orange-lined triggerfish by coral in beautiful blue water - stock photo. Credit: treetstreet/Getty Images)

On a recent kayaking trip, CrowdScience listener Lanier sliced through his right thumb, putting it out of action for a while. This made life difficult, as he couldn’t button his shirt, tie his shoelaces or type efficiently on his smartphone. Missing the use of his thumb made him wonder: since opposable thumbs are so advantageous to those of us who have them, why didn’t they evolve in more species? Host Marnie Chesterton unpicks the evolution of our own unique thumbs with the help of paleoanthropologist Tracy Kivell, learning how our grip compares to that of other animals. We discover why mammals like horses and dogs have no use for thumbs, and why we humans don’t have opposable big toes. Meanwhile, at Taronga Zoo in Sydney, Australia, senior keepers Tarryn Williams Clow and Bec Russell-Cook introduce us to two different marsupials. Humphrey the koala has not one but two thumbs on each hand. Why did koalas develop this anatomical quirk when their closest living relative, the wombat, has spade-like digits? Dr Mark Eldridge from the Australian Museum shares his hypothesis. And what if we, too, had another thumb? Marnie tries on a robotic Third Thumb, built by designer Dani Clode. Dani has collaborated with neuroscientists from the Plasticity Lab at the University of Cambridge. She tells us what the Third Thumb has revealed about the human brain and how we control our digits. Presented by Marnie Chesterton Produced by Cathy Edwards and Margaret Sessa Hawkins for the BBC World Service(Photo: Kung-Fu Koala - stock photo Credit: Alex BOISSY / Getty Images)

Stefan Rotter, theoretical physicist exploring anti‑lasers and perfect absorbers. Jeremy Baumberg, nanophotonics expert who manipulates light with hands‑on demos. They discuss destructive interference with lasers, the anti‑laser that traps and absorbs coherent light, and why cancelling everyday incoherent light like sunlight is far more challenging.

Maria Konnikova, writer and psychologist who turned decision‑making research into poker success; Rachel Croson, economics professor who studies gambling behavior; Kit Yates, mathematical biologist who explains probability puzzles. They explore why people avoid option A, the middle‑option bias, Monty Hall and switching, the gambler’s fallacy versus hot hand, and how poker exposes our decision biases.

CrowdScience listener Namrata and presenter Chhavi Sachdev have something in common. They both get more tanned in the summer in the United States than back home in India. Namrata wants to know why she came back from her run in Boston with such a deep tan and doesn’t have the same experience in India. She’s got quite a few theories herself and wonders if it’s to do with the angle of the sun, pollution or humidity. Chhavi talks to dermatologist Neelam Vashi, who’s based in Boston, to find out how we tan and what protects us from the sun. She meets Julian Groebner at the World Radiation Centre in Switzerland who compares the data in India and the United States for CrowdScience and comes up with a surprising answer. She also talks to Indians in Mumbai who share their attitudes to tanning and what steps they take to protect themselves from the heat of the sun. Presenter Chhavi Sachdev Producer Jo Glanville Editor Ben Motley(Photo: Woman sunbathing on sun lounger by swimming pool. Credit: IndiaPix/Getty Images)

Professor Alex Jordan, an evolutionary biologist who studies animal cognition, explains the mirror‑test methods. Professor Culum Brown, leader of Macquarie’s Fish Lab, explores smell and recognition. Dr Lauren Nadler, a reef fish social behavior researcher, examines shoaling and stress. They discuss visual and olfactory cues, individual odour signatures, imprinting, and whether mirror-test results mean fish recognize themselves.