Why Though? with Dr. Matt Agnew

A cheetah? A race car? A rocket? All great guesses. All completely wrong. The fastest thing on Earth is something you can't hold in your hand... and understanding it means understanding lightyears, the speed of light, and why space distances break normal numbers.Dr Matt Agnew runs the ultimate speed race from Usain Bolt all the way to the speed of light, and explains what a lightyear actually is along the way. Spoiler... most adults get it wrong.What you'll learn:Usain Bolt tops out at around 44 kilometres per hour... the slowest in this race by a long wayA cheetah sprints at 100 to 120 kilometres per hour... basically a furry rocketAn F1 car reaches around 350 kilometres per hour... blink and it's goneNASA's Parker Solar Probe is the fastest human-made object at 690,000 kilometres per hourLight travels so fast it feels instant... and in one second it can circle the entire Earth about seven timesA lightyear isn't time, it's distance... how far light travels in one whole year, about 9.5 trillion kilometresThe closest star to Earth after our Sun is Proxima Centauri, just 4.2 lightyears awayKey Science Ideas:Speed of light: About 300,000 kilometres per second... the ultimate speed limit of the universeLightyear: A unit of distance, not time... how far light travels in one whole yearProxima Centauri: The closest star to Earth after our Sun, 4.2 lightyears awayParker Solar Probe: NASA's spacecraft and the fastest human-made object ever builtAstronomical scale: Why scientists need special units like lightyears to measure enormous distances in spaceFun Experiment: The Lightyear Myth Buster Ask three people in your house or school what a lightyear is. Most will say it's a unit of time. They're wrong... it's distance. Explain that a lightyear is how far light travels in one year, about 9.5 trillion kilometres. You've just done your first myth-busting science experiment, and you didn't need a single piece of equipment.Why Though? The show for little scientists who love asking big questions. Follow or subscribe so you never miss an episode.Why Though? The show for little scientists who love asking big questions. Follow or subscribe so you never miss an episode.Follow Dr Matt Agnew: Instagram: instagram.com/drmattagnew TikTok: tiktok.com/@drmattagnew YouTube: youtube.com/@whythoughpod Website: drmattagnew.comFind Why Though? podcast across the internet and share with your friends!Instagram: instagram.com/whythoughpodTikTok: tiktok.com/@whythoughpodFacebook: facebook.com/whythoughpod

Have you ever walked outside on a bright sunny day and suddenly sneezed... with no dust, no pepper, no cat fluff anywhere? Just sunshine and a sneeze? There's a real science reason behind it.Dr Matt Agnew investigates the sun sneeze mystery. What even is a sneeze? Why does bright light trigger one for some people? And why does it run in families?What you'll learn:Sneezing is your body's nose cleaning button... a blast of air that clears anything annoying from your mucous membraneWhen bright sunlight hits your eyes, your brain urgently signals blink and squintFor about 1 in 4 people, the blink button and the sneeze button sit really close together in the brain... so pressing one accidentally bumps the otherScientists call this ACHOO Syndrome... short for Autosomal Dominant Compelling Helio-Ophthalmic OutburstSun sneezing is linked to your genes, which means it can run in familiesSun sneezes won't hurt you... but stop before the sneeze hits if you're on a bike or crossing the roadKey Science Ideas:Mucous membrane: The sticky lining inside your nose that catches dust, germs and anything annoyingOptic nerve: The nerve that carries signals from your eyes to your brainACHOO Syndrome: The scientific name for sun sneezing... and yes, the acronym was absolutely intentionalGenes: The instructions inside your body that decide things like eye colour, height, and apparently whether sunshine makes you sneezeReflex: An automatic body response your brain triggers without you choosing itFun Experiment: The Family Sun Sneeze Survey Ask everyone in your family whether they sneeze when they look at bright light. Try a torch in a dark room if the sun isn't cooperating. Keep track of who does and who doesn't. If sun sneezing runs in your family, you'll start to see a pattern... and you'll have just conducted your first genetics experiment at the kitchen table.Why Though? The show for little scientists who love asking big questions. Follow or subscribe so you never miss an episode.Follow Dr Matt Agnew: Instagram: instagram.com/drmattagnew TikTok: tiktok.com/@drmattagnew YouTube: youtube.com/@whythoughpod Website: drmattagnew.comFind Why Though? podcast across the internet and share with your friends!Instagram: instagram.com/whythoughpodTikTok: tiktok.com/@whythoughpodFacebook: facebook.com/whythoughpod

Here's something nobody tells you. Most of a fart has absolutely no smell. So what's actually making everyone pinch their nose?Dr Matt Agnew investigates the science of farts. How do smells actually work? What is a fart made of? And why do some foods make the whole situation so much worse?What you'll learn:Smells are tiny invisible particles floating in the air that your olfactory receptors grab and send to your brainA fart is gas made by bacteria in your intestines while they break down foodMost fart gas has absolutely no smell... nitrogen, hydrogen, carbon dioxide, oxygen and even methane are all odourlessThe real culprit is hydrogen sulfide... just 1% of a fart but enough to clear a roomFoods like beans, eggs, broccoli, brussels sprouts, garlic, onion and cheese all produce more hydrogen sulfideMost people fart between 10 and 20 times a day... farts are natural, healthy, and a sign your body is doing its jobAstronauts on the International Space Station have to think carefully about farts because the gas can be trapped and even flammableKey Science Ideas:Olfactory receptors: The tiny parts inside your nose that detect smell and send signals to your brainBacteria: Tiny living things in your intestines that help break down food... and make gas while doing itHydrogen sulfide: The gas responsible for that rotten egg smell... and basically every bad fart everIntestines: The long tube where food gets broken down after leaving your stomachMicrobiome: The community of bacteria living inside your body doing useful work every dayFun Experiment: The Food Fart Tracker Pick two days this week. On day one eat a meal with plenty of broccoli, beans or eggs. On day two eat a meal without any of those. Pay attention to what happens a few hours after each meal. That difference is hydrogen sulfide in action... your gut bacteria working harder on certain foods and producing more of that one very specific gas. Science is everywhere, even when you'd rather it wasn't.Why Though? The show for little scientists who love asking big questions. Follow or subscribe so you never miss an episode.Follow Dr Matt Agnew:Instagram: instagram.com/drmattagnewTikTok: tiktok.com/@drmattagnewYouTube: youtube.com/@whythoughpodWebsite: drmattagnew.comFind Why Though? podcast across the internet and share with your friends!Instagram: instagram.com/whythoughpodTikTok: tiktok.com/@whythoughpodFacebook: facebook.com/whythoughpod

Lightning and thunder happen at exactly the same time. So why does the flash always arrive before the boom?In this episode of Why Though?, Dr Matt Agnew explains how static electricity builds up inside storm clouds, what lightning actually is, why thunder is the sound of super-heated air exploding outward, and how a simple counting trick lets you measure how far away a storm is using nothing but your eyes, ears, and a few seconds.What you'll learn:Static electricity happens when electrons jump from one surface to another... like the zap from a doorknob after shuffling across carpet in socksInside storm clouds, ice and water particles bump and swap electrons until a massive charge builds upWhen the charge gets big enough, it jumps to the ground as a giant electrical spark... lightningLightning heats the surrounding air hotter than the surface of the Sun, so fast the air explodes outward as a shockwave... and that shockwave is thunderLight reaches your eyes almost instantly, but sound travels about one kilometre every three secondsThat gap between flash and boom is how far the storm is from where you're standingKey Science Ideas:Electron: A tiny particle with a negative electric chargeStatic electricity: Built-up charge that can suddenly discharge... the giant version is lightningElectrical discharge: Charge moving rapidly to balance itself outShockwave: A fast-moving pressure wave made when air expands suddenly... thunder is exactly thisSpeed of light vs speed of sound: Light arrives almost instantly, sound takes about three seconds per kilometreFun Experiment: The Balloon Static Trick Blow up a balloon and rub it on your hair or a dry jumper. Hold it close to your hair and watch the strands lift up toward it. That's static electricity... the same force that builds up inside storm clouds, just in a much safer, much smaller version. No storm required.Flash-to-Bang Storm Distance Trick Next time there's a storm outside, watch for a lightning flash from indoors. Start counting... one, two, three. When you hear the thunder, stop and divide your number by three. That's roughly how many kilometres away the lightning struck. Three seconds is one kilometre, six is two, nine is three. If thunder follows almost immediately, the storm is very close... stay inside and away from windows.Why Though? The show for little scientists who love asking big questions. Follow or subscribe so you never miss an episode.Follow Dr Matt Agnew: Instagram: instagram.com/drmattagnew TikTok: tiktok.com/@drmattagnew YouTube: youtube.com/@whythoughpod Website: drmattagnew.comFind Why Though? podcast across the internet and share with your friends!Instagram: instagram.com/whythoughpodTikTok: tiktok.com/@whythoughpodFacebook: facebook.com/whythoughpod

Have you ever sniffed your dog's paws and noticed they smell kind of like Doritos? Not because your dog is secretly snacking on chips... because of something much more microscopic.In this episode of Why Though?, Dr Matt Agnew investigates the tiny living world on your dog's paws. What are bacteria and yeast? Why are dog paws such a perfect home for microbes? And what are they actually doing in there that smells exactly like corn chips?What you'll learn:Dog paws smell like Doritos because of tiny living things called bacteria and yeastDog paws are a perfect microbe home... warm, slightly moist, and picking up dirt and crumbs on every walkTwo bacteria called Proteus and Pseudomonas are usually responsible for that cheesy corn chip smellThe scientific word for this tiny community is the microbiome... and your dog has one living right on their pawsYour own body has trillions of bacteria... even more than human cellsThe Dorito smell is usually totally normal... but red, itchy or sore paws mean a trip to the vetKey Science Ideas:Bacteria: Single-celled organisms found almost everywhere, including on your dog's pawsYeast: A type of fungus... the same kind that helps bread riseMicrobiome: The community of tiny living things on and inside a bodyMicrobes: The scientific word for tiny living things like bacteria and yeastPseudomonas and Proteus: The two bacteria most responsible for that corn chip smellFun Experiment: The Microbe Hotel Take a small piece of bread and leave it in a warm, slightly damp spot for a few days. Watch what grows on it. That fuzzy stuff is mould... a close relative of the yeast living on your dog's paws. Warmth plus moisture plus a tiny bit of food equals microbes moving in. Sound familiar? That's exactly the same recipe as a dog's paw. Once you've had a good look, wrap it up carefully and pop it in the bin... don't open it indoors once the mould gets going.Why Though? The show for little scientists who love asking big questions. Follow or subscribe so you never miss an episode.Follow Dr Matt Agnew: Instagram: instagram.com/drmattagnew TikTok: tiktok.com/@drmattagnew YouTube: youtube.com/@whythoughpod Website: drmattagnew.comFind Why Though? podcast across the internet and share with your friends!Instagram: instagram.com/whythoughpodTikTok: tiktok.com/@whythoughpodFacebook: facebook.com/whythoughpod

Fish spend their whole life in water. But do they actually drink it? Turns out the answer depends entirely on which fish you ask.In this episode of Why Though?, Dr Matt Agnew dives into what thirst really is, why saltwater and freshwater fish handle water in completely opposite ways, and why sharks are the cleverest rule-breakers in the ocean. Plus a kid in a shark costume makes an appearance. Obviously.What you'll learn:Thirst is your body's alert system... and your body is about 60% waterSaltwater fish live in super salty water, so water leaks out of their bodies... they drink seawater to survive and their gills filter the extra salt outFreshwater fish have the opposite problem... water rushes into their bodies, so they barely drink at all and pee constantly to stay balancedSharks keep a chemical called urea in their bodies that helps water flow in naturally through their skin and gills... no drinking requiredSharks have been in the ocean for over 400 million years... longer than trees have existed on landKey Science Ideas:Salinity: How salty water isOsmosis: Water moving from a less salty area to a more salty area through a membrane like skin or gillsHomeostasis: Keeping the body's internal conditions just right so everything works properlyUrea: The chemical sharks use to stay hydrated without drinking seawaterGills: A fish's built-in filter system for managing salt and waterFun Experiment: The Gummy Bear Grow-Off Grab three cups and label them Fresh, Salty, and Super Salty. Add plain water to the first, two teaspoons of salt to the second, and four teaspoons to the third. Drop a gummy bear into each cup, make a prediction, then check back after two hours and again the next morning.The fresh water gummy swells up the most as water rushes in. The salty one grows a little. The super salty one barely changes at all... the saltier the water outside, the less water moves in. That's osmosis... the exact same process fish use to manage water in their bodies every single day.Treat the gummies as science props and wash hands after handling.Why Though? The show for little scientists who love asking big questions. Follow or subscribe so you never miss an episode.Follow Dr Matt Agnew:Instagram: instagram.com/drmattagnewTikTok: tiktok.com/@drmattagnewYouTube: youtube.com/@whythoughpodWebsite: drmattagnew.comFind Why Though? podcast across the internet and share with your friends!Instagram: instagram.com/whythoughpodTikTok: tiktok.com/@whythoughpodFacebook: facebook.com/whythoughpod