CrowdScience

Philip Laven, an independent rainbow expert, demonstrates how sunlight refracts and reflects in water droplets to create rainbows. Retired professor Raymond Lee explains that rainbows lack a fixed size, emphasizing their angular dimensions based on perspective. Aerial photographer Colin Leinhardt shares his experience capturing a stunning full circular rainbow from a helicopter, showcasing its unique beauty. The fascinating discussion reveals how context impacts our perception of a rainbow's size and introduces concepts like secondary rainbows and the 3D nature of these atmospheric wonders.

Marie Bannier-Hélaouët, a postdoctoral researcher, details the fascinating biology of tears, revealing that humans produce three types: basal, reflex, and emotional. Ad Vingerhoets, an expert in clinical psychology, shares insights into the social and evolutionary functions of crying, suggesting it signals helplessness and fosters connection. The podcast also explores heart-rate studies showing potential calming effects of tears and discusses why women tend to cry more, diving into the complex emotional landscape of human tears.

Join Professor Syamsidik, a tsunami mitigation expert from Indonesia, and Hiroshi Sato, a diving instructor who led recovery efforts in Japan, as they explore how tsunamis impact marine life. They discuss how tsunami waves are generated and the minimal effects on deep-sea creatures. Professor Emile Okal explains the mechanics of tsunami waves and their destructive potential as they reach shore. Additionally, Sato shares stories of clearing debris and restoring fisheries post-2011 disaster, highlighting the long-term ecological consequences of tsunami debris.

In this thought-provoking discussion, psychologist Susan Blackmore shares her transformative out-of-body experience and her lifelong quest to understand Near-Death Experiences (NDEs). Neuroscientist Jimo Borjigin presents groundbreaking findings on brain activity during cardiac arrest, suggesting that these experiences might be linked to physiological phenomena. Meanwhile, Dr. Christopher Timmermann explores parallels between NDEs and psychedelic states, probing the role of DMT. Together, they unveil the science behind these enigmatic experiences and their implications for consciousness.

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 terrifying as possible. And we hear from horror film music composer, Mark Korven, who creates tension and fear using an invention he calls ‘the apprehension engine’. He speaks to BBC Naturebang’s Becky Ripley who has been investigating sounds that scare us and their evolutionary origins. Presenter: Anand Jagatia Producer: Jonathan Blackwell (Photo: Couple watch horror movie with blanket to cover their heads. Credit: WC.GI via Getty Images)

In this intriguing discussion, Nick Balfour, a pollinator ecologist at the Royal Botanic Gardens Edinburgh, shares his expertise on hoverflies and their vital roles in ecosystems. He highlights the often-overlooked life stages of insects, including caterpillars and larvae, emphasizing the need for conservation efforts towards these unsung heroes. Listeners learn practical gardening tips to support insect populations, from tolerating weeds to understanding the importance of native plants. Balfour also discusses the impressive benefits hoverflies offer in agriculture, like boosting avocado yields.

How would you record a special moment? Maybe you could take a photograph, film a little video, or record some audio. We have lots of ways of recording what life LOOKS and SOUNDS like, but is the same true for the other senses? What if you wanted to record the smells that greet you on entering your favourite restaurant? Or record the way your loved ones hand feels in yours? These are the questions on the mind of listener Aravind, from California in the USA. He wants to know if there are any ways of recording and reproducing sensory experiences like taste and smell, or physical touch. Anand Jagatia is on the case, and is smelling, tasting, and quite literally FEELING his way to the answer. From a multi-sensory movie experience in Valencia, Spain, to the fascinating history of the pioneers of ‘scented cinema’, through to the ground-breaking “haptic technology” which is enhancing the capabilities of our sense of touch. Both for us, and for the robots which do the jobs we don’t want to. Presenter: Anand Jagatia Producer: Emily Knight Editor: Ben Motley(Photo: Woman making ASMR sounds with microphone and perfume on yellow background, closeup - stock photo. Credit: Liudmila Chernetska via Getty Images)

Atoms are the building blocks of our world. Many have been around since right after the Big Bang created the universe nearly 14 billion years ago. And if life on Earth is made of atoms that are from all the way back then... will those atoms keep existing forever? That’s what CrowdScience Listener Rob in Australia would like to know. Caroline Steel investigates the immortality of atoms by travelling to CERN, the world’s largest particle physics laboratory located along the border of France and Switzerland. There, theoretical physicist Matthew McCullough explains whether the smallest atoms can decay or survive the test of time. Physicist Marco van Leeuwen from Nikhef, the National Particle Physics Laboratory in the Netherlands, gives Caroline a behind-the-scenes tour of the ALICE experiment and the Large Hadron Collider at CERN. She learns how atoms are smashed at incredibly high speeds, and whether that might spell the end of an atom. And all life on earth is made up of atoms, but how does a collection of tiny particles become a living being? Astrobiologist Betül Kaçar from the University of Wisconsin, Madison, breaks down how life works from an atomic point of view. Presenter: Caroline Steel Producer: Imaan Moin Editor: Ben Motley (Photo: Hands cupping a glowing atom in the studio - stock photo. Credit: Paper Boat Creative via Getty Images)

Listener Jude in Canada wants to know why some animals are black and white. Why do zebras risk being so stripy? Why do pandas have such distinct marking? And do they have something in common? Presenter Caroline visits Pairi Daiza, a zoo in Belgium. Together with her guide for the day, Johan Vreys, she looks at these weird and wonderful animals up close. First, she visits three zebras having breakfast. Ecologist Martin How from the University of Bristol explains his ingenious experiment involving horses with zebra blankets. Next on the tour is the giant panda which, according to Prof Tim Caro from the University of Bristol, looks at the way it does to camouflage in snowy forests in China. But there are many more animals to see, and many more reasons to be monochrome, including the penguin and its tuxedo-like colouration. Hannah Rowland, senior lecturer at the University of Liverpool explains that it might have more than just a single function. It turns out, scientific answers aren’t always black and white. Presenter: Caroline Steel Producer: Florian Bohr Editor: Ben Motley(Photo: The zebra was running gracefully running in the green water. Credit: Surasak Suwanmake/Getty Images)

Sometimes in science, when you try to answer one question it sparks even more questions. The CrowdScience inbox is a bulging example of that. We get tons of new questions every week and many of those are following up on episodes we’ve made. Sometimes you want us to go deeper into part of the answer, or sometimes a subject intrigues you so much that it inspires further questions about it. In this episode presenter Caroline Steel is on a mission to answer some of those questions. The CrowdScience episode How do fish survive in the deep ocean? led listener Ivor to wonder what sort of vision deep sea fish might have. On hand to answer that is Professor Lars Schmitz, Kravis Professor of Integrated Sciences: Biology, at Claremont McKenna College in the USA Sticking with vision, we also tackle a question inspired by the CrowdScience episode Do we all see the same colour? For years listener Catarina has wondered why her eyes appear to change colour. Professor Pirro Hysi, ophthalmologist at the University of Pittsburgh, sheds some light on that subject. In India, Rakesh listened to the CrowdScience episode Will the Earth ever lose its moon? and wondered about Jupiter’s many moons. The European Space Agency’s Ines Belgacem is working on a new mission to study Jupiter’s moons. She explains which of the giant planet’s ninety seven moons are ones for Rakesh to watch. We also hear how the episode Why can’t my dog live as long as me? caught the attention of listener Lisa... and her cat. She had us falling in love with the long history of falling cats and the scientists who study them. Caroline is joined by Professor Greg Gbur, physicist at the University of North Carolina, Charlotte in the USA and author of Falling Felines and Fundamental Physics. Could this episode of follow up questions lead to an episode investigating the follow up questions to these follow up questions? Have a listen and, who knows, maybe you’ll find yourself inspired to email crowdscience@bbc.co.uk Presenter: Caroline Steel Producer: Tom Bonnett Editor: Ben Motley(Photo: Innovation and new ideas lightbulb concept with Question Mark - stock photo Credit: Olemedia via Getty Images)