Episode notes
What is fire, and why does watching it hold our attention in a different way from scrolling on your phone? Hannah Fry and Michael Stevens start with the science of a flame: why it glows, what its different colours reveal, and why fire is a series of chemical reactions rather than a single substance. Then they travel back to a time before wildfires could burn on Earth, and ask how early humans learned to use and make it. Could keeping a fire alive have helped our ancestors learn to plan and cooperate? And what happens when we replace the quiet pull of a hearth with the endless pull of a…
The Rest Is Science
by Goalhanger · English · Tech & Science
Join mathematician Professor Hannah Fry and science creator Michael Stevens (Vsauce) as they dig into the weird scientific questions that often go unexplored. Welcome to The Rest Is Science, a show that sits in the fascinating space between what we think we know, and what we actually know. Why do we assume we understand things like time, randomness, or even gravity? Once you start questioning…
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S1 · E93 · 7 Oct 2026 · 42 minNew
What Was A Mammoth Doing At The Bottom Of The Sea?
Hannah surprises Michael with a mammoth bone from Doggerland, the lost Ice Age land that once joined Britain to mainland Europe, and now lies beneath the North Sea. Who lived there, what roamed it, and how did an entire landscape disappear under the waves?Then it's your questions: where did "cool" come from as a word for style, and how did it stick around for so long? What on earth is "skank face"? And what are Hannah and Michael reading right now?-------------------For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit…
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4 Oct 2026 · 51 min
Why Do We Turn on Innocent People?
Why do we turn on innocent people? A convincing story, a suspicious glance and suddenly everyone’s an armchair detective. But what happens when the crowd gets it completely wrong? Hannah Fry and Michael Stevens explore the psychology of false accusations, witch hunts and mob mentality, starting with Richard Jewell, the security guard hailed as a hero after the 1996 Atlanta Olympics bombing before becoming the target of a media storm. From the Salem witch trials and the Satanic Panic to internet detectives and social media pile-ons, they investigate how a hunch snowballs into certainty. Along…
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S1 · E94 · 30 Sep 2026 · 41 min
Hacking The Kendama With Physics
Michael hands Hannah a kendama, the Japanese cup-and-ball toy, and asks her to land a single catch. Then he brings out one built for him by Adam Savage of MythBusters and explains why a heavier kendama is a completely different physics problem. A kendama looks like a children's toy. It is really a pendulum, a lesson in angular momentum and a catching problem borrowed from spacecraft docking. Michael and Hannah get into why the swing timing barely changes when the ball gets heavier, why the trick is to match the ball's velocity rather than grab at it, why bending your knees on the catch is…
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S1 · E89 · 23 Sep 2026 · 1 hr 5 min
The Fluid Dynamics of Fountain Pens
The wait is finally over: Hannah Fry introduces Michael Stevens to her beloved fountain pen collection and the beautiful physics behind how fountain pens work. From a £20 Lamy Safari to vintage Waterman and Montblanc pens, Hannah explains how capillary action, surface tension, air pressure and carefully engineered feeds control the flow of fountain pen ink. Michael tests the collection, chooses his favourite and discovers why the most expensive pen is not necessarily the nicest to write with. Then Hannah and Michael answer your questions: which words are terrible at their jobs, how do…
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S1 · E88 · 20 Sep 2026 · 49 min
Dying In Space, Trapped Water, and What's Hidden In Pi?
Almost every human who has ever lived has one thing in common: they were born and died on Earth. Except for three people. Hannah Fry and Michael Stevens uncover the extraordinary story of Soyuz 11, the Soviet cosmonauts who became the only humans ever to die in outer space, and what their deaths meant for the future of human spaceflight.But that raises a bigger question: what exactly is trapped on Earth, and what can escape? Is the water left inside discarded plastic bottles being locked away forever? Is Earth itself slowly leaking water into space? Can you really trap a monkey simply…
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S1 · E87 · 16 Sep 2026 · 57 min
How Codes Were Used To Hack The Telegram Business
What if a single strange word could save you a fortune? In this episode Michael opens up a Victorian telegram code book and explores how users compressed long messages into brief coded words to outwit the per word charge of the telegraph system. Coded language turned everyday phrases about everyday events into something that looked like nonsense to outsiders, and why that secrecy was often a side effect of economy rather than espionage, and how operators learned to live inside this clipped new dialect of distance and delay. ------------------- For more information about Cancer Research UK,…
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S1 · E86 · 13 Sep 2026 · 43 min
Why Your Body Needs Gravity
Does space travel make astronauts younger? Professor Hannah Fry and Michael Stevens explore Einstein’s twin paradox, time dilation and NASA’s famous Twins Study with astronauts Scott and Mark Kelly. After Scott Kelly spent 340 days aboard the International Space Station, he returned milliseconds younger than his identical twin. But microgravity had also affected his eyesight, bones, blood, gut microbiome, body temperature, genes and telomeres. So what exactly happens to the human body in space, and which changes remain after astronauts return to Earth? In this episode, Hannah and Michael…
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S1 · E85 · 9 Sep 2026 · 42 min
What Is Collagen All About?
Do collagen pills live up to their promises for skin and joints and healthy ageing? In this episode, Hannah and Michael examine what collagen actually is and how the body makes and uses it, before looking closely at whether collagen supplements survive digestion and reach the skin in any meaningful form. ------------------- For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit https://www.cancerresearchuk.org/our-research/rest-is-science Cancer Research UK is a registered charity in England and Wales (1089464), Scotland (SC041666),…
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S1 · E84 · 6 Sep 2026 · 55 min
The Threshold of Human Sensation
What is the smallest thing you can possibly feel? Michael Stevens and Professor Hannah Fry journey through varying levels of perception, from the faintest touch on skin to the faintest trace of flavour and odour, and on to the remarkable question of whether the eye can register a single particle of light. This is an exploration of human senses at their most sensitive, blending physics and neuroscience with everyday experience to reveal where our biology draws the line between nothing and something, and what about emotion... how do we feel those? What is the smallest thing you can…
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S1 · E83 · 2 Sep 2026 · 49 min
The Scale of the Universe
The scale of the universe stretches from the Planck length, the smallest scale physics can describe, to the observable universe, the largest thing we can see. Travel inward from one and outward from the other by powers of ten and they meet at something astonishingly familiar: the size of a human egg cell. Michael Stevens (VSauce) takes Professor Hannah Fry on a journey through powers of ten, from quarks and protons and DNA to bananas and pyramids and on to planets and galaxies, to explore where we sit in the scale of the universe. Along the way they ask whether the Planck length could be the…
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