CrowdScience

Courtney Shewitt, from the Assiniboine Park Conservancy, shares her insights on sea lions' puzzling habit of swallowing rocks, known as gastroliths. Oliver Wings, director of the Natural History Museum in Bamberg, showcases fascinating discoveries from his vast collection, including surprising finds like gemstones. They discuss the various purposes of gastroliths, such as aiding digestion and buoyancy control. The conversation also touches on other rock-swallowing species, like ostriches and penguins, highlighting the complexity of animal behaviors in this quirky phenomenon.

On the banks of the St Lawrence River in Quebec stands a 100-year-old lighthouse. While initially built to help boats navigate one of Canada’s most difficult waterways, the Point-de-Père site now also holds a different responsibility: it is a key reference for measuring sea levels around the entire North America continent. But this is all set to change. With the development of new satellite technology, the tricky task of measuring sea levels is being updated - which could mean mountains around North America get brand new official heights. In this episode we revisit a question from CrowdScience listener Beth, who wondered about the elevation signs she saw scattered along a mountainous road, indicating how high above sea level she was. As sea levels rise, will all the elevation signs need repainting? And how do you measure sea level, anyway? The height of an enormous pile of rock like Ben Nevis, or Mount Everest feels unchangeable. But we measure them relative to the nearest patch of sea, which is where our story becomes complicated. Unlike water in a bath, sea level is not equal around the world. In fact, nothing on earth - not the sea, the shore or the mountains - is stable or constant, so the question of what you measure from and to becomes incredibly tricky. But that hasn’t stopped scientists risking life and fingers to use an ever-evolving array of technologies to find answers. Join host Marnie Chesterton as she dives into the mechanics of the latest sea level technology, and how it could make a big difference to understanding our unpredictable world. Presenter: Marnie Chesterton Producer: Julia Ravey and Marnie Chesterton Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano and Jana Holesworth Studio Manager: Emma Harth(Image: Elevation Sign Post, Rocky Mountain National Park. Credit: Stephanie Beverungen via Getty Images.)

Host Anand Jagatia tackles gravity - a fundamental force of the universe yet also an everyday mystery that has baffled several listeners. Can you outrun it? Or at least use it to get fitter? If it varies, does that mean that you weigh less, depending on where on earth you stand? And if it’s the force of attraction between any objects with mass, are you technically more attractive after eating a massive cake? Professor Claudia de Rham from Imperial College London explains the basics of gravity, while we discover the best place on earth to weight ourselves, with Professor Paddy Regan from Surrey University and NPL Fellow in Nuclear and Radiation Science and Metrology. Anand takes a very fast spin on a special chair to experience extra gravity, thanks to Professor Floris Wuyts from the University of Antwerp, Kings College London and Minister of Science of Asgardia. And finally, we talk to an expert lined up at the other end of a hypothetical hole through the earth: Professor Richard Easther from the University of Auckland, New Zealand. What would happen if we fell straight through the earth? CrowdScience finds gravity a force to be reckoned with. Presenter: Anand Jagatia Producer: Marnie Chesterton Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano and Jana Bennett-Holesworth Studio Manager: Jackie Margerum and Duncan Hannant Photo: Anand Jagatia experiencing extra g-force

Are food allergies higher in the West than the East? UK-based listener Jude wants to know the answer. Her daughter-in-law Min didn’t know anyone with food allergies when she was growing up in South Korea and thinks that they’re not so common there. Host Alex Lathbridge investigates. Along the way, he finds out what makes us sensitive to food allergies and how much that depends on our environment. He volunteers to have an allergy test, learns what triggers food allergies and tries to discover what lies behind their increase around the world. Alex talks to some of the leading experts on food allergies in search for an answer to our listener’s question: Paul Turner breaks down what happens in our bodies when we have an allergic reaction; Jennifer Koplin explains why Australia tops the league table for food allergies and Michael Levin reveals what he found out in his ground-breaking research in South Africa comparing urban and rural populations. We also hear from Hana Ayoob, who grew up in Singapore and the UK, who describes what it’s like to suffer from multiple food allergies and describes the difference in cultural attitudes. Finally, we turn to Sooyoung Lee in South Korea to see if our listeners are right about the difference in rates for food allergies between East and West. Presenter: Alex Lathbridge Producer: Jo Glanville Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Duncan Hannant(Image: Young Asian father with cute little daughter grocery shopping for dairy products in supermarket Credit: d3sign via Getty Images)

In this engaging discussion, evolutionary biologist Kit Opie and biological anthropologist Katie Starkweather dive into the complexities of human relationships. They explore whether monogamy is a social construct or part of our evolutionary history. Opie shares insights from primate mating systems, while Starkweather reveals how different cultures approach non-monogamy. The chemistry of love is also unpacked, showcasing how neurochemicals like oxytocin influence bonding, shedding light on the age-old question of whether one partner is truly better than many.

The wetness of water seems blindingly obvious - but dive into the science and things aren’t so clear. CrowdScience listeners Rachel and Callum were washing their hands one day and it got them thinking about wetness. Why does water feel the way it does? And what makes a liquid wet? To find out, presenter Anand Jagatia takes a closer look at the behaviour of liquids with materials scientist Mark Miodownik, and finds out why they might not be as wet as we think. We learn what’s really behind the sensation of feeling something wet on your skin, with the help of physiologist Davide Filingeri and PhD student Jade Ward. And we turn to a philosopher, Vanessa Seifert, and a chemist, Tim Neudecker, to puzzle out exactly how many water molecules you need before the property of wetness emerges. Presenter: Anand Jagatia Producer: Anand Jagatia Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Bob Nettles and Andrew Garratt(Image: A photo of a droplet falling into a body of water Credit: Flaviu Cernea / 500pxvia Getty Images)

Delve into the nostalgic world of tangerines, exploring how they vanished from our holiday traditions. Discover their origins in Ancient China, and learn about the unique Dancy variety through the insights of a fruit detective. Uncover the complex journey of citrus breeding, which has led to sweeter but less diverse fruits. Listen to a citrus supplier share tales of forgotten varieties and witness a listener's emotional reunion with the tangerines of their childhood. A sweet exploration of nostalgia and biodiversity!

Explore the enchanting hues of the sky, from vibrant sunsets to the surprising science behind color perception. Discover why we see blue during the day and the rare occurrences when green appears, like in a rainbow or the elusive green flash. Delve into the role of sunlight scattering and how our brains interpret these colors. Journey to the Arctic to witness the mesmerizing northern lights and learn how solar particles create stunning auroras. This fascinating investigation uncovers the beauty and complexity of what paints our sky.

Hugo Duminil-Copin, a Fields Medal-winning mathematician at the University of Geneva, dives into the enigma of randomness. He demonstrates how our brains often misinterpret random patterns, even during playful experiments like coin flips. The conversation explores whether anything is truly random and the philosophical implications of predictability, especially in quantum physics. Additionally, insights from cognitive neuroscience reveal why humans seek order amid chaos, shedding light on the intricate relationship between randomness and perception.

In a poignant exploration of memory, the podcast dives into infantile amnesia, revealing why we often forget early childhood experiences despite their significance. Personal stories intertwine with scientific insights, examining how caregiving and culture shape our recollections. Listeners learn about innovative experiments with toddlers and fascinating animal studies that suggest those memories might still linger in our brains. The discussion also uncovers the emotional impacts linked to lost memories and the complexities of memory retrieval.