CrowdScience

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 - stock photo Credit: IndiaPix/IndiaPicture via 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.

Trevor Cox, a Professor of Acoustic Engineering, explores the intriguing realm of silence and how it’s measured, revealing that absolute silence is an illusion. Marta Moita, a Neuroscientist, shares her findings about how rats associate silence with potential threats, hinting at our own instincts. The discussion delves into the dual nature of silence as both a potential alarm and a source of relaxation, depending on context. Marnie’s visit to an anechoic chamber uncovers the unsettling side of complete quiet, challenging our understanding of silence.

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 between the life cycle of cicadas and the fruiting of a peach tree. Armed with that knowledge, can you really make time move faster for tree and insect alike? Presenter: Anand Jagatia Producer: Robbie Wojciechowski Editor: Ben Motley(Photo:Cicada on Hosta Leaf - stock photo Credit: KenWiedemann via Getty Images)

Join neuroscientist Sophie Scott, an expert on laughter, as she spills the secrets behind how our bodies produce sounds of joy. Evolutionary psychologist Gil Greengross takes us back to Darwin's musings on laughter's roots and shares studies that reveal humor's heritability. Meanwhile, Nancy Segal regales us with the touching story of the 'Giggle Twins,' two siblings reunited after decades who laughed alike despite being raised apart. Together, they explore the fascinating blend of genetics and environment that shapes our laughter.

Join a hilarious end-of-year quiz where presenters tackle quirky scientific questions! Discover why animals swallow stones and how cats defy physics by landing on their feet. Dive into stellar brightness with insights about Vega and Sirius, and uncover cultural takes on time from 'island time' to 'Indian stretchable time.' Plus, learn the fascinating reasons behind infantile amnesia and hear entertaining anecdotes involving ladybirds and a runaway cow tail. Who will take the crown in this wacky showdown?

Matt Mailey, an environmental physiologist from Loughborough University, delves into our body's fascinating responses to cold, including vasoconstriction and shivering. In contrast, Gunnhild Birgitta Sætre, an associate professor at the Arctic Safety Centre in Svalbard, offers insights on suitable clothing and mental preparedness for icy conditions. They explore how cultural background and biological factors influence individuals’ experiences of cold, showcasing the complex interplay of biology and environment in our survival strategies.

Robert Karlsson, a musician and the innovative director of Between Music's Aquasonic project, dives into the world of underwater performances. He shares insights on how tank design and instrument modifications can enhance acoustics beneath the surface. Discover the fascinating effects of submerging guitars, including altered tones and sound dynamics. Karlsson also discusses the development of unique instruments like the rotacorda, tailored specifically for aquatic environments, paving the way for a new genre of music.

In this insightful discussion, guests Yan Li, a geographical sciences professor, Chris Sansom, a solar desalination expert, and climate scientist Alan Condron explore innovative ways to green deserts. Yan reveals how changing land surfaces with solar and wind farms could double Sahara rainfall. Chris explains solar-powered desalination techniques to turn seawater into fresh water, while Alan proposes towing icebergs to parched regions. They highlight potential ecological risks and advocate for sustainable, community-led solutions to revive arid landscapes.

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.