Why Though? with Dr. Matt Agnew

The ground beneath your feet feels completely still... but the continents are actually moving all the time.

In this episode of Why Though?, Dr Matt Agnew explains why continents drift across the Earth, how tectonic plates slowly carry them around the planet, and how that movement creates mountains, deep ocean trenches and earthquakes.

What you'll discover:

• Continents move just a few centimetres each year... about as fast as your fingernails grow
• Long ago, every continent was joined together in one giant supercontinent called Pangaea
• Earth's crust is made of enormous tectonic plates rather than one solid shell
• When plates collide they can push up mountain ranges like the Himalayas
• When one plate slides underneath another, it creates deep ocean trenches through a process called subduction
• Earthquakes happen when pressure builds between stuck plates before suddenly being released

Why Though? The show for little scientists who love asking big questions. Subscribe so you never miss an episode.

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It looks like magic. It makes spooky fog that pours down instead of floating up. And it never leaves a puddle. So what is dry ice actually doing?

Dr Matt Agnew unpacks the weird science of dry ice, what sublimation is, why the fog pours downward like a waterfall, and why dry ice behaves so completely differently from the ice in your freezer.

What you'll learn:

• Normal ice is frozen water... dry ice is frozen carbon dioxide, the gas we breathe out
• Dry ice skips the liquid step entirely... straight from solid to gas with no puddle
• Scientists call that process sublimation, one of the most interesting phase changes in science
• The fog is mostly not carbon dioxide at all... it's water vapour from the surrounding air getting chilled so fast it becomes visible
• Cold air and carbon dioxide are both heavier than regular warm air, so the fog pours downward like a fog waterfall
• Dry ice is essentially a natural fog machine used in theatres, film sets and Halloween displays worldwide

Key Science Ideas:

• Sublimation: When a solid skips the liquid stage and goes straight to gas
• Carbon dioxide: The gas we breathe out, and what dry ice is made of
• Water vapour: Invisible water in the air that becomes visible when it gets suddenly cold
• Phase change: When matter moves between solid, liquid and gas states
• Density: Why cold air and carbon dioxide both sink rather than rise

Safety note: Dry ice is extremely cold and must only be handled by adults wearing insulated gloves. It should only be used in well ventilated spaces. This is a watch and learn 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.com

Find Why Though? podcast across the internet and share with your friends!

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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 way
• A cheetah sprints at 100 to 120 kilometres per hour... basically a furry rocket
• An F1 car reaches around 350 kilometres per hour... blink and it's gone
• NASA's Parker Solar Probe is the fastest human-made object at 690,000 kilometres per hour
• Light travels so fast it feels instant... and in one second it can circle the entire Earth about seven times
• A lightyear isn't time, it's distance... how far light travels in one whole year, about 9.5 trillion kilometres
• The closest star to Earth after our Sun is Proxima Centauri, just 4.2 lightyears away

Key Science Ideas:

• Speed of light: About 300,000 kilometres per second... the ultimate speed limit of the universe
• Lightyear: A unit of distance, not time... how far light travels in one whole year
• Proxima Centauri: The closest star to Earth after our Sun, 4.2 lightyears away
• Parker Solar Probe: NASA's spacecraft and the fastest human-made object ever built
• Astronomical scale: Why scientists need special units like lightyears to measure enormous distances in space

Fun 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.com

Find Why Though? podcast across the internet and share with your friends!

Instagram: instagram.com/whythoughpod

TikTok: tiktok.com/@whythoughpod

Facebook: facebook.com/whythoughpod

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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 membrane
• When bright sunlight hits your eyes, your brain urgently signals blink and squint
• For 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 other
• Scientists call this ACHOO Syndrome... short for Autosomal Dominant Compelling Helio-Ophthalmic Outburst
• Sun sneezing is linked to your genes, which means it can run in families
• Sun sneezes won't hurt you... but stop before the sneeze hits if you're on a bike or crossing the road

Key Science Ideas:

• Mucous membrane: The sticky lining inside your nose that catches dust, germs and anything annoying
• Optic nerve: The nerve that carries signals from your eyes to your brain
• ACHOO Syndrome: The scientific name for sun sneezing... and yes, the acronym was absolutely intentional
• Genes: The instructions inside your body that decide things like eye colour, height, and apparently whether sunshine makes you sneeze
• Reflex: An automatic body response your brain triggers without you choosing it

Fun 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.com

Find Why Though? podcast across the internet and share with your friends!

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Facebook: facebook.com/whythoughpod

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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 brain
• A fart is gas made by bacteria in your intestines while they break down food
• Most fart gas has absolutely no smell... nitrogen, hydrogen, carbon dioxide, oxygen and even methane are all odourless
• The real culprit is hydrogen sulfide... just 1% of a fart but enough to clear a room
• Foods like beans, eggs, broccoli, brussels sprouts, garlic, onion and cheese all produce more hydrogen sulfide
• Most people fart between 10 and 20 times a day... farts are natural, healthy, and a sign your body is doing its job
• Astronauts on the International Space Station have to think carefully about farts because the gas can be trapped and even flammable

Key Science Ideas:

• Olfactory receptors: The tiny parts inside your nose that detect smell and send signals to your brain
• Bacteria: Tiny living things in your intestines that help break down food... and make gas while doing it
• Hydrogen sulfide: The gas responsible for that rotten egg smell... and basically every bad fart ever
• Intestines: The long tube where food gets broken down after leaving your stomach
• Microbiome: The community of bacteria living inside your body doing useful work every day

Fun 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/drmattagnew

TikTok: tiktok.com/@drmattagnew

YouTube: youtube.com/@whythoughpod

Website: drmattagnew.com

Find Why Though? podcast across the internet and share with your friends!

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Facebook: facebook.com/whythoughpod

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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 socks
• Inside storm clouds, ice and water particles bump and swap electrons until a massive charge builds up
• When the charge gets big enough, it jumps to the ground as a giant electrical spark... lightning
• Lightning heats the surrounding air hotter than the surface of the Sun, so fast the air explodes outward as a shockwave... and that shockwave is thunder
• Light reaches your eyes almost instantly, but sound travels about one kilometre every three seconds
• That gap between flash and boom is how far the storm is from where you're standing

Key Science Ideas:

• Electron: A tiny particle with a negative electric charge
• Static electricity: Built-up charge that can suddenly discharge... the giant version is lightning
• Electrical discharge: Charge moving rapidly to balance itself out
• Shockwave: A fast-moving pressure wave made when air expands suddenly... thunder is exactly this
• Speed of light vs speed of sound: Light arrives almost instantly, sound takes about three seconds per kilometre

Fun 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.com

Find Why Though? podcast across the internet and share with your friends!

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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 yeast
• Dog paws are a perfect microbe home... warm, slightly moist, and picking up dirt and crumbs on every walk
• Two bacteria called Proteus and Pseudomonas are usually responsible for that cheesy corn chip smell
• The scientific word for this tiny community is the microbiome... and your dog has one living right on their paws
• Your own body has trillions of bacteria... even more than human cells
• The Dorito smell is usually totally normal... but red, itchy or sore paws mean a trip to the vet

Key Science Ideas:

• Bacteria: Single-celled organisms found almost everywhere, including on your dog's paws
• Yeast: A type of fungus... the same kind that helps bread rise
• Microbiome: The community of tiny living things on and inside a body
• Microbes: The scientific word for tiny living things like bacteria and yeast
• Pseudomonas and Proteus: The two bacteria most responsible for that corn chip smell

Fun 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.com

Find Why Though? podcast across the internet and share with your friends!

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Facebook: facebook.com/whythoughpod

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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% water
• Saltwater 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 out
• Freshwater fish have the opposite problem... water rushes into their bodies, so they barely drink at all and pee constantly to stay balanced
• Sharks keep a chemical called urea in their bodies that helps water flow in naturally through their skin and gills... no drinking required
• Sharks have been in the ocean for over 400 million years... longer than trees have existed on land

Key Science Ideas:

• Salinity: How salty water is
• Osmosis: Water moving from a less salty area to a more salty area through a membrane like skin or gills
• Homeostasis: Keeping the body's internal conditions just right so everything works properly
• Urea: The chemical sharks use to stay hydrated without drinking seawater
• Gills: A fish's built-in filter system for managing salt and water

Fun 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/drmattagnew

TikTok: tiktok.com/@drmattagnew

YouTube: youtube.com/@whythoughpod

Website: drmattagnew.com

Find Why Though? podcast across the internet and share with your friends!

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Pluto used to be the ninth planet in our Solar System. Then in 2006 everything changed. Dr Matt Agnew explains why... and it's a better story than you think.

In this episode of Why Though?, we travel back to 1930 when astronomer Clyde Tombaugh spotted a tiny moving dot in the night sky and made one of the biggest discoveries in space history. We find out what happened when scientists discovered Eris... a Pluto-like world that was even heavier than Pluto. And we learn the three-rule checklist that decides what actually counts as a planet.

Of course Matt's dog Pluto makes a cameo.

What you'll learn:

- Pluto was discovered in 1930 and taught as the ninth planet for over 70 years

- Better telescopes revealed a whole region of icy worlds beyond Neptune called the Kuiper Belt

- Scientists found Eris... similar to Pluto but even heavier, which forced a big question

- To be a planet, a world must orbit the Sun, be round, and clear its neighbourhood

- Pluto does two out of three... but it hasn't cleared its neighbourhood

- Pluto became a dwarf planet in 2006... and it's still completely incredible

Key Science Ideas:

- Kuiper Belt: A region beyond Neptune full of icy objects

- Planet definition: The three-rule checklist astronomers use to classify worlds

- Clear its neighbourhood: Being the gravitational boss of your part of space

- Dwarf planet: Orbits the Sun, is round, but hasn't cleared its neighbourhood

- Scientific change: Science updates its ideas when new evidence appears

Fun Experiment: The Planet Checklist Challenge

Scientists use a three-rule checklist to decide what counts as a planet. Now it's your turn to be the astronomer.

Grab five objects from around the house... a footy, a mandarin, a marble, a 50 cent coin, and a tin of baked beans. These are your space objects. For each one, ask the three planet questions:

- Does it orbit a star? Walk it around a lamp

- Is it round? Check its shape

- Is it the boss of its space? Could it push everything else out of its way, or does it have to share?

Only objects that pass all three rules get to be a planet. Then here's the twist... change one rule and see what happens. That's exactly what scientists did in 2006. They didn't move Pluto. They just got clearer about the rules. And Pluto couldn't pass the third test.

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.com

Find Why Though? podcast across the internet and share with your friends!

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TikTok: tiktok.com/@whythoughpod

Facebook: facebook.com/whythoughpod

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Ever heard someone talk after a helium balloon and suddenly sound like a tiny squeaky mouse? There's real science behind it... and it's weirder than you think.

In this episode of Why Though?, Dr Matt Agnew investigates the helium voice mystery. Why do balloons float? Why does sound travel faster through helium? And how does all of that flip a normal voice into instant chipmunk mode? Plus we find out about a super-heavy gas that does the exact opposite... making voices go deep and booming.

What you'll learn:

• Helium is less dense than air... that's why balloons float
• Your vocal cords and throat work together to shape sound
• Sound travels faster through helium, which shifts the way your voice sounds
• Your brain hears those shifted sounds as higher and squeakier
• Scientists call the frequencies that shape your voice formants... helium scrambles them

Key Science Ideas: states of matter, density, vocal cords, resonance, formants.

Fun Experiment: Hum "mmmm" with your mouth closed then slowly open it wider. Hear the change? That's resonance in action... same science, no gas required.

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.com

Find Why Though? podcast across the internet and share with your friends!

Instagram: instagram.com/whythoughpod

TikTok: tiktok.com/@whythoughpod

Facebook: facebook.com/whythoughpod

Hosted on Acast. See acast.com/privacy for more information.