CrowdScience

Have you ever found yourself doing something – perhaps getting a glass of water, eating a snack, or even sitting on the toilet – without remembering making the decision to do it? CrowdScience listener Mohammed certainly has. It’s left him wondering: does he really have free will, or is he a puppet of his biological processes? To try and find the answer, we start in the brain. Presenter Caroline Steel meets neuroscientist Uri Maoz, from Chapman University in the US, to explore the controversial research into what happens when we make decisions. Does neuroscience say that we are free to make our own choices, or does our brain make decisions outside of our consciousness? Then there’s our guts - they’re home to trillions of microbes; independent living creatures that we couldn’t live without. But could these tiny organisms influence more than our digestion? Harriët Schellekens, from University College Cork in Ireland, shares her cutting-edge research into the surprising ways our microbes shape us. And perhaps…

Where do shells come from? CrowdScience listener Tamsyn got in touch, a little embarrassed, confessing that she had managed to reach her twenties without realising that shells are made by living creatures. Suddenly, her curiosity ran wild and she asked CrowdScience to investigate how these sea creatures have the architectural prowess to make shells in delicate ornamental shapes with beautiful colours and patterns. The job of sea-creature-investigator-in-chief falls to presenter Marnie Chesterton. She heads to the Natural History Museum in London, UK, where they have more shells than they can keep count of. Researcher Dr Suzanne Williams pulls out drawer after drawer of amazingly varied molluscs for Marnie to marvel at. Then, it’s off to the beach to go shell hunting with Dr Leanne Melbourne, Senior Curator of Climate Change and the Dynamic Coast for Norfolk Museums in the UK. They look at the structure of shells, and Leanne explains how a soft mollusc is able to make a hard shell so sturdy they can survive…

CrowdScience listener Gurmeet in India wants to know if plants can sense that we're around. She started wondering about this at a wellness centre where she was encouraged to hug a tree. She enjoyed the experience, but what about the tree? Did it enjoy being touched? And is there actually evidence that hugging a tree is good for us? Anand Jagatia talks to scientists about what happens to a plant when it's touched. Molecular biologist Olivier van Aken, from Lund University in Sweden, explains what happens inside a plant's cells – from mimosa whose leaves close up when touched to a Venus flytrap that sees a good opportunity for dinner. Plant biologist Alexander Jones, from the Sainsbury Laboratory at the University of Cambridge, UK, tells Anand how plants process information without a brain: when there's a threat from a hungry insect, it's their hormones that leap into action to defend it. Anand visits Wisley Garden in the UK and meets Ashby Lavelle Sachs, the Royal Horticultural Society's Wellbeing Fellow, who…

CrowdScience listener Devin in Canada has just had a baby. Worried that all the good email addresses might be taken by the time his child needs one, he has already set up an account. But it got him wondering: how many email addresses belong to people who have died? From websites and blogs to email accounts, social media profiles, gaming avatars and even our conversations with AI, we’re all leaving behind a trail of digital footprints that can outlive us. So what happens to them when we die? Are they deleted, recycled or preserved? And who gets to decide? Presenter Anand Jagatia travels beyond the digital veil and into the internet’s afterlife to find out. Professor Edina Harbinja from the University of Birmingham Law School in the UK, an expert in ‘digital death’ and ‘post-mortem privacy’, explains how the law has struggled to keep pace with our digital lives. While it’s relatively straightforward to decide who inherits physical letters and photographs, what happens when those memories are stored in emails…

CrowdScience listener Lisa, who is from South Africa but now lives in the UK, has been a vegetarian for many years. Sometimes though, she still finds herself craving meats – like spaghetti bolognese or a burger. To satisfy these cravings, she eats ‘alt-meats’, products meant to look and taste like meat but made from vegetables. This has her wondering though, are these alternative meats better for the planet than actual meat would be? And what about her health? Given that many of these foods are highly processed, would eating meat be better for her? Presenter Chhavi Sachdev speaks to food systems researcher Charlotte Bunge from Uppsala University on Sweden, US health journalist Alice Callahan and researcher Christopher Gardner from Stanford University in the US to try and pick apart the positives and negatives of replacing ‘real’ meat with ‘pretend’ meat, before visiting an Indian company producing meat that was grown in a lab. Presenter: Chhavi Sachdev Producer: Margaret Sessa-Hawkins Editor: Ben Motley…

Your heart pounds, your chest tightens, your stomach drops and your legs feel weak and shaky. Your palms are sweating and a tingling rush spreads through your arms and fingertips as your brain is overwhelmed with feelings of tension and fear. And yet, you’ve asked for this. You wanted to be on this ride, at this theme park, hurtling towards the ground at a frightening speed. But why? An adrenaline rush is the body’s fight-or-flight response to intense fear, stress or excitement. It sends signals from the brain to the body, releasing hormones and redirecting the flow of blood around our veins. It’s designed to help us survive dangerous situations – so why would we deliberately want to put ourselves into those situations, just to feel the rush? That’s the question from CrowdScience listener Gunnar, aged 11, in Washington State USA. He wants to know why we try and seek an adrenaline rush by doing wild and crazy things, and CrowdScience’s wild and crazy Alex Lathbridge is on the case. Andy Hine, from the…

Some fish can deliver electric shocks with four times the voltage of the electricity in your plug sockets at home . Crowdscience listener Mouhammed in Cameroon was stunned by this, so he charged us with finding out how they do it. Presenter Caroline Steel heads to Bayreuth in Germany to meet some eels who have this amazing ability. Dr Stefan Schuster and Susanne Proschke introduce us to their collection of electric fish, and help us conduct some experiments to work out how the fish are wired. We’ll be diving into electric fishes' anatomy, learning how a specialised organ allows them to generate massive voltages of electricity. Harold Zakon from the University of Texas will help us understand their evolutionary history, while Brazilian ecologist Nonato Junior takes us on a journey into the currents of the Amazon River where electric eels live. And we’ll answer a question that has boggled philosophers, thinkers, and scientists for over 2000 years. If these fish can stun a human, a crocodile or even a horse,…

CrowdScience listener Matt wants to know why he's warm blooded. He started thinking about this when he was watching some ants during the recent heatwave in Europe and wondered why their blood didn't boil. What are the pros and cons of being warm-blooded like us or cold-blooded reptiles like lizards? Caroline Steel meets evolutionary biologist Dr Manuel Leal from the University of Missouri in the US, who explains the differences between ectotherms (cold-blooded animals) and endotherms (warm-blooded animals). She discovers that the terms cold blooded and warm blooded are actually misleading, because reptiles can reach a high body temperature and some might even become warmer than us. She talks to Simon Hodder, Professor of Environmental Ergonomics at Loughborough University in the UK, who describes how our bodies regulate heat, how we cool down when we get too warm and how that's all controlled by our brains. Caroline also gets to meet some hedgehogs in the wild with Julia Nowack, an ecophysiologist from…

Why is it hard to concentrate, and why does it feel like such hard work? The CrowdScience inbox is full of questions like that, so for this show we’re concentrating on concentration and focusing on how we focus. We’ll be answering questions about the extra energy the brain uses when we’re concentrating, whether mental effort can tire you out more than physical effort, why we zone out when faced with a difficult task and how the ability to multitask is governed by our overall cognitive load. To find the answers, presenter Alex Lathbridge is paying attention to a team of experts. Psychology professor Sophie Leroy from the University of Washington in the USA studies the impact of being interrupted on our ability to perform, cognitive neuroscientist Professor Salvador Soto-Faraco from the Universitat Pompeu Fabra in Barcelona, Spain researches how sight, sound and touch are blended together by the brain, and psychology professor Polly Dalton runs the Attention Lab at Royal Holloway University in London, UK.…

Tuberculosis kills more than a million people every year. It’s the world’s leading cause of death from a single infectious agent. This is despite the fact that we've had a cure for TB since the 1940s and a vaccine that’s over 100 years old. So why is TB still causing so many people to die? That’s what CrowdScience listener John in Tanzania wants to know, and presenter Marnie Chesterton is on the case. Over in Paris, she’s joined by Dr Claas Kirchhelle, historian of science, medicine and technology at French National Institute of Health and Medical Research (INSERM) to look into the history and efficacy of the vaccine, known as BCG. As Dr Maximiliano Gutierrez, Associate Research Director at the Francis Crick Institute adds, the BCG is both effective and ineffective, protecting children well against severe TB, but offering inconsistent and often poor protection in adults. He also explains that antibiotics are a trickier treatment than we might expect. Over in Kenya’s Kibera slums, Janet tells us her about her…

Stare up at the night sky, and if you’re lucky, you might see a shooting star. Some people might make a wish, but CrowdScience listener Scott in California in the USA, thinks differently. He’s wondering how dangerous they might be. Shooting stars are actually meteors, ending their incredible journey whizzing through the depths of space by burning through our atmosphere, and crashing down to earth. And Scott’s not wrong to worry about them! In May 2026, an enormous meteor exploded off the coast of Massachusetts, causing a loud sonic boom before crashing into the ocean, releasing the equivalent energy of 300 tons of TNT! So, should we be worried? Marnie Chesterton is on the case. In Australia, Hadrien Devillepoix is the chief scientist for the Desert Fireball Network, which tracks meteors through the sky, and tries to recover any meteorites which make it to earth. He explains just how many of these smaller space rocks arrive on our planet every day, how many of them survive long enough to make it to the…

We’re delving into the CrowdScience archive to give you another chance to hear an award-winning show from 2025. CrowdScience listener Dorit has a problem. She wants the tiles in her new bathroom to be arranged randomly but, no matter what she does, it still looks like they form some kind of pattern. This has got Dorit thinking about randomness – what is it, how do you create it, why do we find it so hard to recognise, and is anything really random at all? And if nothing is truly random, does it mean that everything is theoretically predictable? Tiling your bathroom is a much more existential problem than you might have thought. Never afraid of a question, whether big (is everything pre-determined?) or small (how do I tile my bathroom?), CrowdScience is on the case. Anand Jagatia heads to Switzerland to meet Hugo Duminil-Copin, a mathematician at the University of Geneva who specialises in probability theory. On the top floor of an old bank, Hugo has Anand flipping an imaginary coin in a random order. Hugo…

Space missions are searching for evidence of extra-terrestrial life. CrowdScience listener George in Kenya wants to know what could be up there, and if there’s a risk it could harm humanity. With rovers currently analysing samples on Mars, missions searching for the building blocks of life on Jupiter’s icy moons, George’s concern that there could be diseases in space is timely. Presenter Anand Jagatia sets out to try and find an answer while keeping his feet on the Earth. He meets astrobiologist Dr Michaela Musilova, who runs experiments to try and understand what kinds of microbes could survive on other planets. In her work at NASA’s Jet Propulsion Laboratory, she recreates Mars-like environments that test lifeforms’ resilience to the rigours of the Red Planet. And if there are harmful pathogens in space, how do we make sure these missions don't bring them back to Earth? Anand talks to ‘planetary protection officer’ Silvio Sinibaldi from the European Space Agency, who explains what experts are doing to…

CrowdScience listener Liana from Canada got in touch to ask about some very specific rocks she’d seen on an island in Indonesia – jagged, rugged and a very strange shape: hexagonal. They were in long columns, and clicked together like a jigsaw. But what are they, and how did they get there? Across the world in the UK, CrowdScience listener Sarah emailed us to ask about the famous rocks of the Giant’s Causeway in Northern Ireland. What makes them so uniformly hexagonal? Presenter Alex Lathbridge investigates, visiting the Giant’s Causeway to speak to geologist Dr Kirstin Lemon from the Geological Survey of Northern Ireland. She explains how this amazing landscape formed, and why the mythical rocks look the way they do today. We also hear from Dr Alfend Rudyawan from Institut Teknologi Bandung in Indonesia about Liana’s intriguing rocks. Are these distant locations more closely related than you might think? And we look to nature – because angular, uniform hexagons crop up surprisingly often. Professor…

Many plants need pollen from another plant of the same species in order to reproduce, but they don’t have legs so they can’t simply walk around looking for a mate. As a result, many of them rely on animals to transfer pollen from one plant to another. They’ve developed a hugely diverse range of techniques to attract them, including their appearance, taste and smell. CrowdScience listener Alice in the UK wants to know how they have evolved to do this. To try and answer the question, presenter Anand Jagatia goes trekking up a mountain in the Philippines, battling mud and leeches in the hunt for an incredibly rare flower. Rafflesia has evolved to look and smell like rotting meat in order to attract flies, so it’s the perfect example of a plant that goes to fascinating extremes to make sure it gets pollinated. It only blooms for a few days each year, so to find it Anand is going to need the help of scientists at the University of the Philippines Los Baños and Lewis Barrett, Senior Botanical Propagator at the…

“What separates humans from animals, is an interest in the past”. That’s a 900-year-old quote from a textbook that Nigerian listener Taiwo came across, and he wrote to CrowdScience to ask if modern science would agree. Most of us spend time thinking about the past, whether it is nostalgia for a bygone age or just wondering where we put the house keys yesterday. But is that just a human activity or do other animals also ruminate on their history and use it to make decisions? Taiwo wants to know if there is any evidence to show that animals have an interest in the past and if it matters to them. Presenter Caroline Steel has a history of answering questions like this, so she sets out to find an answer. She meets researchers who have found evidence that animals not only remember past events, but use their memory for planning. She talks to neuroscientist Dr Freyja Olafsdottir and discovers that some animals, including rats and mice, have the same brain structure for memory as humans. She meets baby magpies in…

CrowdScience listener Rachel uses Bluetooth headphones on her cycle to work, seamlessly playing music from her phone without using wires. But how does this technology send information through the air? To find out, Rachel and presenter Caroline Steel travel to Cambridge in the UK to meet telecommunications expert William Webb. He explains what Bluetooth signals actually are – and demonstrates why their properties are linked to the invention of leaky microwave ovens. Caroline speaks to Jaap Haartsen, the inventor of Bluetooth, who reveals the hidden meaning of its logo, and what the name has to do with an ancient Viking king. And she learns how a new flavour of “low energy” Bluetooth is having an unexpected application: helping ecologists like Damien Farine understand animal behaviour. Which leads her to an old tobacco barn in Switzerland, to meet researcher Bettina Almasi and her team – along with some very cute baby barn owls. Presenter: Caroline Steel Producer: Anand Jagatia Editors: Ben Motley & Ilan…

CrowdScience listener Haruka has been making origami cranes out of paper since she was a child. Creating one out of a cloth napkin, however, was a next-level challenge. It gave her a new appreciation of paper’s excellent foldability, and made her wonder: what is it about paper’s structure that means it remembers its creases? We set out to unfold her question as we peer into paper’s secrets. First stop: Frogmore, the world’s first mechanised paper mill. Here, Dr Steven Mann is on hand to explain the papermaking process, the chemistry of paper, and why that makes for a foldable sheet. Host Caroline Steel tries to make a paper crane, assisted by both listener Haruka and origami teacher Toshiko Kurata, who also introduces us to an array of paper types. Each type folds differently, and, with the help of a trusty microscope, Professor Bill Sampson from the University of Manchester reveals why. Finally, we see just how complex paper folding can get, meeting Professor Tomohiro Tachi from the University of Tokyo, and…

CrowdScience listener George is showing Alex Lathbridge around a small, dark, and extremely hot shed, just outside the city of Accra in Ghana. Inside are row after row of shelves, stacked high with bulging grow-bags. And out of some of them, gorgeous cascades of oyster mushrooms are bursting into bloom. We’re on George’s mushroom farm, and he’s noticed something interesting. Even though the conditions in his grow-shed are tightly controlled – they have exactly the same food, water, and light as each other – nevertheless, they respond differently. Some are more vigorous than others, some bloom quicker, others last longer, and some are more tolerant when the conditions change. And this got George wondering. Could ‘brainless’ lifeforms like mushrooms, and plants, have different ‘personalities’? Do they experience the world differently, and live their lives differently from each other? Alex Lathbridge is on the case. He visits the PGRRI, the Plant Genetic Resources Research Centre, for a quick lesson on genetic…

Why is there such a variety of tongues in the animal kingdom? CrowdScience listener Dale has observed that his dog’s tongue is different from his and so is his cat’s. He’d like to know the reason. Caroline Steel visits London Zoo in the UK to find out more about the different types of tongues - from giraffes and birds to lizards. She talks to evolutionary biologist Kurt Schwenk, who explains that the development of tongues made it possible for animals to make the leap from the sea to life on land. Fish could rely on water to help them swallow food, but air and gravity required a whole different mechanism for having dinner. But why is there such a variety of tongues between species - from the forked tongue of a snake to the rough tongue of a cat? And does it all come down to our diets? Researcher Callum Ross reveals how he’s pioneered a new technique for investigating how animals use their tongues when they eat and drink, and why tongues are so important for swallowing. Presenter: Caroline Steel Producer: Jo…

CrowdScience listener Daniel in Accra, Ghana is an introvert. Or at least, he thinks he is. And he’s worried that his preference for quiet spaces and lower social interaction might be holding him back in life. But what is introversion really? How do introverts and extroverts see the world differently? And is it better to be one or the other? Presenter Alex Lathbridge spends his working days talking to interesting people like Daniel. He loves meeting people, and talking to them too, yet he also thinks that deep down, he might be an introvert. To understand how and why people come to be introverted or extraverted, and what’s happening in the brain, he pays a visit to neuroscientist Dr Thomas Tagoe from the University of Ghana Medical school, for a peek inside the mind. Turns out, introverts aren’t shy, and definitely aren’t anti-social either, despite what people might assume. The difference is more about how we process stimulation, and at what point we find it all a bit too much to process. Although sometimes…

Why do we feel itchy? So many listeners have emailed in with questions about itchiness, and presenter Anand Jagatia on the case. We explore why we itch, the different types of itch, the different causes, and why scratching can help with the itchy sensation. Anand puts your questions to an expert panel: Dr Sonja Ständer, professor of Dermatology and Neurodermatology at the University of Münster and and Gil Yosipovitch, Professor of Dermatology at the Miller School of Medicine at University of Miami. Also joining them from the University of Hull in the UK is Dr Henning Holle who studies the psychology of itch. He’s got an itchy game for Anand, Sonja and Gil to play in the studio, but is it really as simple as he’s letting on? Presenter: Anand Jagatia Producer: Tom Bonnett Editor: Ben Motley (Photo: Young women have skin problems, irritation on her skin, skin infection itching red rash, arm scratching with hands, isolated over yellow background - stock photo - Credit: Arnav Pratap Singh via Getty Images)

As our oceans warm due to climate change, sea levels are rising. It ought to be straightforward – as water gets warmer, it increases in volume. All the world’s oceans are connected, so how come sea levels are rising at different rates around the world, and even falling in some places? CrowdScience listener Alison in Australia wants to know the science behind the mystery. Presenter Anand Jagatia travels to the Philippines to investigate. The country is being particularly affected by the issue, with its more than 7,500 islands experiencing sea level rises that are double the global average. On Palawan Island, in the east of the country, he speaks to people whose homes and livelihoods are being put at risk by rising waters. He also visits the Philippine Coast Guard in Manila and speaks to Commander James Barandino, from their Marine Environmental Protection division, to hear how their work is being affected by sea level rises and the flooding it causes. Dr Charina Lyn Repollo from the University of the…

CrowdScience listener Jeroen finds it hard to remember people's faces - and he wants to know why. He wonders if it's to do with getting older and if there’s any way of improving. Presenter Caroline Steel has the same problem and is keen to find an answer too. She meets Professor Zaira Cattaneo, a neuroscientist based in Italy who researches face perception. Zaira has discovered which parts of the brain are engaged in facial recognition. She explains how we recognise faces and why ageing could be a factor in Jeroen’s difficulty. Caroline travels to Bournemouth in the UK to meet researcher Professor Sarah Bate, who assesses Caroline's ability to recognise faces and explains the causes of face blindness. And she compares notes with fellow CrowdScience presenter Marnie Chesterton, who also has difficulty remembering faces. Around two per cent of the population have the condition. Could there be a reason why more than a third of CrowdScience presenters experience face blindness? If you’ve got a science question…

CrowdScience listeners Dougie and Molly have been wondering what happens to animals when they die, and whether there are animals that hold rituals to mark the passing of one of their kin. Presenter Caroline Steel is on the case, trying to work out what happens to the bodies of animals when they die. Dougie and Molly say they rarely see animal carcasses where they live - so where do they all go? Dr Sarah Perkins of Cardiff University in the UK runs a research project called Roadlab, which logs how quickly the bodies of animals killed by traffic disappear, and she thinks she might have a clue. Caroline joins her on a hunt through the undergrowth for animals, and answers. And when animals lose a member of their flock, herd or school, do they indulge in rituals that look anything like a funeral? Caroline meets Dr Kaeli Swift, an ecologist at the University of Washington in the US, who has some surprising evidence from her research into bereaved crows. Meanhile, in Botswana, Mathale ‘Metal’ Mosheti is a safari…

Salt can be found in almost every kitchen in the world. But how did this seemingly simple ingredient become the world's favourite flavour enhancer? This week, Crowdscience sets out to uncover why these tiny crystals have such a powerful effect on us. We explore the magic behind this tiny mineral that has shaped our tongues, our culture, and our cravings. Our investigation begins with CrowdScience listener George, who heard from a friend that if he added a few grains of salt to his morning coffee, he could make it taste less bitter. Following some light investigation at his local coffee chain, he began wondering why salt make things taste more delicious. To try and find an answer, presenter Anand Jagatia heads to a salt mine in Austria with Daniel Bradner, an archaeologist from the Natural History Museum of Vienna. The mine is 200 kilometres from the sea, so where does all the salt come from? In London, UK, we meet Adriana Cavita, a chef who helps us explore how salt transforms what we eat: sharpening aromas,…

Is the world sitting on a ticking time bomb? CrowdScience listener Christel recently watched a documentary about a volcanic eruption in 536 AD that left her native Sweden under a cloud of ash for three years. It got her thinking, do we know when this could happen again? With more than 300 volcanoes – and 24 of them listed as currently active – the Philippines is a country where trying to predict eruptions has huge real world consequences. Presenter Anand Jagatia travels to Manila to meet the scientists at PHIVOLCS, the Philippine Institute of Volcanology and Seismology, including the head of their Volcano Monitoring and Eruption Prediction Division, Mariton Antonia Bornas, to find out how they try to predict volcanic activity in the country and help make sure communities are evacuated out of harm’s way. He travels with the team to Taal volcano, which experienced violent eruptions in 2020 and has been active again this year, to visit the observatory monitoring for signs of future activity and to hike to the…

Listener Bart in Australia sees invasive species in his area almost every day – rabbits, foxes, and cats. They were transplanted to Australia from Europe more than 100 years ago, but seem to be thriving in their new home. This got him wondering: how are they going to evolve, now that they are in a new habitat? Can we predict what future evolution will look like based on what we already know? To find out, Marnie Chesterton visits Sandy Ingelby at the Australian Museum, who manages the mammal collection. She shows Marnie how indigenous Australian animals have evolved to suit where they live. On the island of Tasmania, Marnie meets the famous Tasmanian Devil and keeper Jono Thomas. Andy Flies from the University of Tasmania explains how the devil is evolving in real-time in response to a health crisis. So what might the invasive species in Bart’s backyard look like over the next 100 years? We’ll find out, with a little bit of help from palaeontologist Matt McCurry and millions of murderous toads. Presenter:…

CrowdScience listener Po wants to know whether AI could one day replace all human jobs. And while he requests that CrowdScience continues to be hosted by people, it made presenters Caroline Steel and Anand Jagatia wonder – could an AI really present this show? To find out more about how AI models work and what they’re capable of, Caroline Steel speaks to AI journalist Alex Hern from The Economist. She creates an AI version of herself with Nicky Birch, Innovation Lead for the BBC’s generative AI program, and hears how the BBC is attempting to navigate the ethical use of this new technology. Anand Jagatia speaks to phonetician Prof James Kirby about how synthetic AI voices have become so convincing, as well as why they still sound slightly unnatural. And Anand and Caroline ponder whether there could ever be a place for AI presenters on the airwaves. Presenters: Caroline Steel and Anand Jagatia Producer: Anand Jagatia Additional production: Lorna Stewart Editor: Ben Motley (Photo: Mirror image of presenter…

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)

CrowdScience listener Kassy in India wants to know if there’s any science to support the practice of ‘manifesting’ – the idea that you can make your wishes come true just by writing down your goals and sending your dreams out to the universe. Is it just a wacky belief or can it be backed up by research? Caroline Steel looks at the evidence to see if manifesting works. She talks to researcher Lucas Dixon in Australia, who has found that people who believe in manifesting are more likely to take risky financial decisions or end up bankrupt. She meets neuroscientist Sabina Brennan in Ireland who argues that psychology has already proven that our thoughts and beliefs shape our reality, through cognitive behavioural therapy for example. So there is evidence to show that some of the techniques in manifesting can work. Caroline also talks to psychologist Gabriele Oettingen in the US, whose research has demonstrated that just thinking about our wishes actually decreases our energy and makes it less likely that we’ll…

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…

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.…

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…

Noise cancelling headphones filter out sound waves that we don’t want to hear. Listener Ahmed in Libya loves wearing his and, as he was listening to them, he had a thought: ‘Could we cancel out light waves in a similar way to how noise cancelling headphones do it?’ He sent his question to CrowdScience and now presenter Alex Lathbridge is getting deep into the physics, to find out if light cancelling devices could replace curtains and shutters. Alex starts at the Ray Dolby Centre in Cambridge in the UK, built to honour Ray Dolby’s invention of noise cancelling technology. In this amazing building he meets Jeremy Baumberg, Professor of Nanophotonics at Cambridge University. With the help of a tuning fork and a laser beams, Jeremy shows Alex that manipulating light is no easy feat. Undeterred, Alex tracks down Stefan Rotter, Professor of Theoretical Physics at Vienna Technical University in Austria. Stefan and his colleagues around the world have been pushing forward the development of a device called the…

CrowdScience listener Griffith in Ghana, isn’t JUST a CrowdScience listener. He’s also a listener to our sister show on the World Service, Unexpected Elements. But he’s noticed something funny. In the weekly Unexpected Elements multiple-choice quiz, the answer is almost NEVER ‘a’. It’s nearly always ‘b’, or ‘c’. Why is this? When we set the quiz, why are we so reluctant to choose option ‘a’? His question leads presenter Alex Lathbridge on a journey into the murky depths of our brain, where he discovers the cognitive biases which so often trip us up in games of chance, or probability. Your brain might be a marvellous machine when it comes to figuring out how to understand the world, but sometimes, in the name of efficiency, it takes clever little short-cuts to the answer. This pragmatic approach to problem solving helps us manage an incredibly complicated world. But occasionally, especially when it comes to mathematics, chance, and probability, it leads us in the wrong direction. With the help of…

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)

There’s something fishy going on in the Czech Republic, where CrowdScience listener Ian lives. He keeps tropical fish, and he’s noticed that when he adds new ones to his tank, they swim with others of the same breed. He wants to know how they recognise each other. Do they know what they look like, and recognise others that look the same, or is there something else going on? Presenter Anand Jagatia takes a deep breath and dives into the science. At the Blue Reef Aquarium in Portsmouth, Dr Lauren Nadler from the University of Southampton introduces us to some Blue Green Chromis fish to look for clues about how and why they form their large social groups. And we explore the smelly world of fish olfaction with Professor Culum Brown from Macquarie University in Sydney Australia. The mirror test is a classic way of trying to understand whether an animal can recognise itself or not. Professor Alex Jordan from the Max Plank institute in Konstanz, Germany explains how scientists place a visible mark on an animal,…

Is silence blood-curdling or blissful? CrowdScience listener Ziqi finds it intolerable and thinks that there’s a good reason for it – silence is so rare in nature that it could be a signal for danger. Presenter Marnie Chesterton is on a mission to test Ziqi’s theory, starting with her own tolerance for silence. She meets acoustic engineer Trevor Cox in the UK to find out whether silence is something we can measure. To do that she steps into an anechoic chamber, a place that’s designed to absorb all sound. In this most silent of silent places, what does silence actually sound like? Marnie also talks to researcher Eric Pfeifer in Germany, who is exploring the impact of spending time in silence and has evidence to suggest that it could be a positive experience. And neuroscientist Marta Moita in Portugal tells Marnie about how rats use silence to detect a threat in their environment. Her discoveries may hold the answer to Ziqi’s question. Presenter Marnie Chesterton Producer Jo Glanville Editor Ben Motley…

Crowdscience listener Ryosuke grew up in Japan, and spent his childhood summers catching cicadas in the park. For people in Japan, the sound of their chirping signals the first true summer day. But until they emerge, these enigmatic insects live underground - often for many years. Ryosuke wants to know how they know the time is right, and CrowdScience is on the case. Presenter Anand Jagatia pieces together the story of the species, and meets the small but dedicated group of academics worldwide who’ve been able to study them. In a field near Girona, Spain, he meets a scientist who’s spent the last twenty years counting them. How will a temperature probe help us work out when they might emerge, and what are they doing underground for so many years anyway? In nearby Barcelona, another scientist cuts open the stem of a tomato plant and Anand watches as the sap flows out. Could this be a clue to how cicadas sense what’s going on above ground? And he meets a cicada breeder in the US who has discovered a link…

CrowdScience listener Limbikani in Zambia is always being told he has his Dad’s laugh, so he set us the challenge of trying to find out whether a laugh can be passed down in our genes or if it’s something we learn from our environment. Presenter Caroline Steel steps into the world of one of the world’s greatest laughter experts, Professor Sophie Scott, neuroscientist at University College London. In her office stuffed with memorabilia of a life filled with fun, they discuss how the shape of our bodies could play a role in how we laugh. Also joining the fun is Dr Gil Greengross, evolutionary psychologist at Aberystwyth University in Wales, UK. Gil tells us how Charles Darwin was the first person to question how laughter evolved. Caroline also speaks to Dr Nancy Segal, Professor of Developmental Psychology and Director of the Twin Studies Center at California State University, Fullerton. Nancy is an expert in studies that demonstrate the role of nature vs nurture in how who we are and how we behave. She tells…

In 2025, the crack team of intrepid presenters here on CrowdScience have been on some incredible adventures. They’ve wondered whether water is wet, and gone a hunt for a missing tangerine. They’ve wondered why animals swallow rocks, imagined what would happen if the earth spun backwards and pondered whether atoms are immortal. But, as the year draws to a close, Anand Jagatia is wondering… have they REALLY been paying attention? Time to put them to the test! In this special programme, Anand gathers the other four presenters into a studio together – Caroline, Alex, Marnie and Chhavi, for an end-of-year quiz – and you can join in at home! Presenters: Anand Jagatia, Caroline Steel, Alex Lathbridge, Marnie Chesterton and Chhavi Sachdev Producer: Emily Knight Editor: Ben Motley (Photo: CrowdScience presenters in the studio with purple background Credit: BBC)

When some people are wandering around in shorts and a t-shirt, others are wrapped up in warm coats and jumpers. How come our responses to cold weather are so different? People have been living in cold environments for thousands of years. So why do some of us struggle with the cold more than others, and what, if any, adaptations have our bodies made to cope in freezing temperatures? CrowdScience listener Anne from the UK is amazed by the warm houses of her neighbours, and wants to know whether her background might have affected her perspective on the cold. Caroline Steel investigates, visiting a laboratory in Loughborough University, UK, that pushes the body to the extreme. Dr Matt Maley explains what happens inside our systems to help us survive the plummeting thermostat and how this adaption can vary from person to person. But it’s not just biological. Our culture impacts our experience of cold too. CrowdScience heads to Norway to meet the global community on the icy Arctic island of Svalbard. There…

Smashing up guitars is a classic rock star activity, but how about drowning them? Seven-year-old listener Cornelius asked CrowdScience to find out what happens if you play a guitar underwater. Could this be the next avant-garde music sensation? Host and amateur musician Caroline Steel tackles Cornelius’ question with the help of one increasingly soggy guitar. The UK’s National Physical Laboratory is our first port of call, with a guitar-sized water tank at the ready, and acoustic scientists Dr Freya Malcher and Ben Ford helping tackle our questions. Since an acoustic guitar’s sound is amplified by its internal chamber, what happens as that chamber starts to fill with water? How about if the whole guitar - strings, body and all - is submerged? What difference does it make if our ears are listening above or below the water? And can special water-adapted microphones help us explore this unusual question, before our guitar disintegrates? Our guitar then heads off on tour to Denmark, where the band Between Music…

Can we turn the world’s deserts green? CrowdScience listener Youcef is captivated by the idea of bringing water back to Earth’s driest landscapes. With sea levels rising and huge stretches of land drying out each year, he wonders whether redirecting seawater inland could offer a solution to both problems. Presenter Alex Lathbridge sets out to investigate starting with a kettle of salty water. Alex speaks to scientists about how deserts form, and how human actions like overgrazing can tip a fragile grassland into a barren landscape. He learns how the brightness of bare sand affects local weather, reducing cloud formation and rainfall. Researcher Yan Li reveals how huge solar and wind farms could darken and roughen the Sahara’s surface enough to double its rainfall, potentially kickstarting a self-reinforcing cycle of vegetation and moisture. But what about deserts where clouds already drift overhead? In the Atacama, one of the driest places on Earth, geographer Virginia Carter shows how fog harvesting nets…

When listener Sakura’s husband came home from his morning walk in Cambridgeshire, UK, he told her about a massive rainbow he’d seen. But when he showed her a picture, she didn’t think it was particularly large. So how big is a rainbow really? Are they always the same size? And if some are bigger than others, is there a limit? To find the answers, presenter Marnie Chesterton meets independent rainbow expert Philip Laven in a pitch-black studio to simulate how a rainbow is formed. He demonstrates how they are created by sunlight, reflecting and refracting in millions of little water droplets. But what does that mean for their size? Raymond Lee, retired professor from the US Naval academy, says that rainbows are not objects and don’t have a linear size, just a specific angular size that’s relative to the person seeing it. But Marnie doesn’t give up so easily – some rainbows still look bigger than others. In her journey to discover other ways to size up a rainbow, Marnie hears from Australian aerial photographer…

Tears of joy, tears of sadness, tears of frustration or tears of pain - humans are thought to be the only animals that cry tears of emotion. CrowdScience listener Lizzy wants to know: why do we cry for emotional reasons? What is its evolutionary benefit? And why do some people cry more than others? It turns out that humans cry three types of tear: basal, reflex and emotional. The first kind keeps our eyes nice and lubricated and the second flushes out irritants such as fumes from the pesky onion, but the reasons for emotional tears are a bit harder to pin down. Using a specially designed tear collection kit, presenter Caroline Steel collects all three kinds of tears. With them safely stashed in tiny vials, she heads to the Netherlands, to Maurice Mikkers’ Imaginarium of Tears. Looking at her crystallised tears under a microscope will hopefully unveil a mystery or two. Marie Bannier-Hélaouët, who grew tear glands for her PhD, explains how the nervous system processes our emotions into tears. But why should we…

Tsunamis destroy buildings, habitats and danger to everything in its path on land. But how do they affect life under the water? That's what CrowdScience listener Alvyn wants to know, and presenter Anand Jagatia is searching beneath the waves for answers. Anand meets Professor Syamsidik who is learning about how tsuanami waves are formed to help protect against future disasters. He runs the Tsunami and Disaster Mitigation Research Center at Universitas Syiah Kuala, Indonesia. With him at this state-of-the-art lab is Dr David McGovern, expert in ocean and coastal modelling at London South Bank University. David tells Anand how the energy of a tsunami is spread across the entire water column. To explain the forces at play, Anand chats to Professor Emile Okal a seismologist from Northwestern University in the United States. Tsunami wave can move as fast as 800 kilometres an hour but, despite this, out at sea you might not notice it - but can the same be said for marine life? We follow the wave as it nears land…

In your final moments, they say, you may walk down a tunnel of light. You might rise above your body, watching the scene below before passing into another world. Perhaps you’ll be met by glowing figures, see your life flash before your eyes, or feel a deep, unearthly calm. These are the stories of people who’ve reached the edge of death and returned. They’re not rare, nor random, and they have a name: near-death experiences. CrowdScience listener Steven in Chile first heard of them during a CPR class and wondered, are they fictitious? Psychologist Susan Blackmore once had an out-of-body experience as a student in Oxford, UK — floating above herself before soaring over the rooftops and dissolving into the universe. That single moment changed everything. She’s spent her career trying to understand what happened, and she believes such experiences are explainable. At the University of Michigan in the US, neuroscientist Professor Jimo Borjigin has done what few have dared: record the dying brain in action. Her…

For some they’re the stuff of nightmares, but many of us can’t get enough of horror films. For Halloween, CrowdScience investigates the science of why we enjoy films that scare the living daylights out of us. CrowdScience listener Maria from Taiwan is one of those people who would rather avoid frightening films, yet her husband loves them and is always trying to get her to watch with him. She wants to know why people like her husband are so drawn to horror films. To try and find out, presenter Anand Jagatia travels to the Recreational Fear Lab in Aarhus, Denmark, which is dedicated to understanding why people frighten themselves for fun. He meets the research lab’s directors Mathias Clasen and Marc Andersen who explain how horror and recreational fear could help us cope better with uncertainty, bond with those we are frightened beside, and perhaps even have some physical health benefits. They also take Anand to a haunted house, called Dystopia, which has used the Recreational Fear Lab’s research to become as…