https://aussiescience.com/silicon/why-can-sand-think/https://aussiescience.com/thumbs/silicon/why-can-sand-think-1280.webpWhy can sand think?Here's something I never understood. The chip in your phone is a sliver of silicon. And silicon, joined to oxygen, is silica, the same compound as quartz and sand. Rock, basically. So how does rock end up doing maths? To answer that, we have to start with an older question. Why does anything conduct electricity at all?https://www.youtube-nocookie.com/embed/umoeUS-qdRU7412026-10-04T00:52:28+00:00yesno https://aussiescience.com/silicon/doping/https://aussiescience.com/thumbs/silicon/doping-1280.webpDoping: a few wrong atoms on purposeLast time, we purified silicon until it was one of the purest things people have ever made. And on its own, it was almost useless: a near-insulator, with a gap of about 1.1 electron volts. The physicist Wolfgang Pauli once called semiconductors a filthy mess, and the mess was impurities. Here's the twist.https://www.youtube-nocookie.com/embed/nuTmrlDrCQo6182026-10-04T00:43:59+00:00yesno https://aussiescience.com/silicon/diode-and-rectifier/https://aussiescience.com/thumbs/silicon/diode-and-rectifier-1280.webpThe one-way street: diodes and rectifiersLast time we left Russell Ohl's cracked silicon rod, p-type on one side and n-type on the other. Where they met, a flashlight made about half a volt, and current flowed far more easily one way than the other. Every phone charger, every LED, every solar panel depends on that boundary.https://www.youtube-nocookie.com/embed/VY2kwwl3FMU6752026-10-04T00:45:30+00:00yesno https://aussiescience.com/silicon/1947/https://aussiescience.com/thumbs/silicon/1947-1280.webp1947: how Bell Labs stumbled into the transistorLast time, we ended on a one-way street. A diode can steer a current, but nothing lets a small signal open or close it, so it can't make a signal bigger. For that you need an amplifier, and in 1947 that meant a glowing glass vacuum tube.https://www.youtube-nocookie.com/embed/6w69YGqgtbI6492026-10-04T00:42:29+00:00yesno https://aussiescience.com/silicon/switch-and-amplifier/https://aussiescience.com/thumbs/silicon/switch-and-amplifier-1280.webpSwitch and amplifier: BJT vs MOSFETLast time, Bell Labs built a little crystal device that let a small signal control a big one. That sounds like getting something for nothing. A whisper goes in, a shout comes out. So where does the extra come from? And how can a few layers of doped silicon steer a current they don't supply?https://www.youtube-nocookie.com/embed/M7QMJjb0ESs6672026-10-04T00:47:40+00:00yesno https://aussiescience.com/silicon/integrated-circuit/https://aussiescience.com/thumbs/silicon/integrated-circuit-1280.webpThe integrated circuit: printing circuits with lightLast time, we met the MOSFET: a switch whose gate holds it on or off for almost no power, and which, for decades, got better as it shrank. So here's the next problem. By 1958, a useful machine needed thousands of parts, all wired together by hand. Modern chips need vastly more, and nobody could solder that many.https://www.youtube-nocookie.com/embed/UaPDw0oBNQo6812026-10-04T00:48:59+00:00yesno https://aussiescience.com/silicon/logic-from-switches/https://aussiescience.com/thumbs/silicon/logic-from-switches-1280.webpLogic from switches: gates, CMOS and the 555Last time, we learned to print switches by the million. But a switch only knows two things: on, and off. It can't decide anything. So how does a pile of switches add up your shopping, or check a password? The trick is that you don't need a switch to think. You need to arrange them, so the arrangement does the thinking.https://www.youtube-nocookie.com/embed/eGG2-SgumO86812026-10-04T00:55:47+00:00yesno https://aussiescience.com/silicon/memory/https://aussiescience.com/thumbs/silicon/memory-1280.webpHow silicon remembers: RAM, ROM and flashLast time, two gates wired in a loop held a single bit. But that bit is lost when the power goes off. Your phone is different. Let the battery go flat, and your photos are still there next week. Yet the app you had open has to start again from scratch. So what does remembering even mean, for a chip?https://www.youtube-nocookie.com/embed/ca88XYhqrQE6822026-10-04T00:24:42+00:00yesno https://aussiescience.com/silicon/special-purpose-silicon/https://aussiescience.com/thumbs/silicon/special-purpose-silicon-1280.webpCPU vs ASIC vs FPGA vs GPULast time, we put logic and memory together. Now, what do we build out of them? Apple's 2024 iPhone 16 Pro answers in an odd way. Its main chip holds a six-core processor, a six-core graphics unit, and a sixteen-core "neural engine". Why three kinds of brain on one chip, instead of one good one?https://www.youtube-nocookie.com/embed/WylSazccP6k7082026-10-04T00:26:17+00:00yesno https://aussiescience.com/silicon/data-centres-and-next/https://aussiescience.com/thumbs/silicon/data-centres-and-next-1280.webpData centres and what's nextLast time, we filled a building with chips. So where does all this go next, and what's stopping it? The short answer is heat. Let's walk into one of those buildings, then look at the industry's tricks for keeping going: light from exploding tin, chips cut into pieces, new materials, and wires made of light.https://www.youtube-nocookie.com/embed/4yx35SoV-UI6952026-10-04T00:27:32+00:00yesno https://aussiescience.com/australian-science/wifi/https://aussiescience.com/thumbs/australian-science/wifi-1280.webpWi-Fi: how CSIRO beat the echoThis season is about things Australians invented or discovered, told honestly. What each one solved, how it works, who shared the credit, and what came before. We'll start with the famous one. You've probably heard that Australia invented Wi-Fi. That's an overstatement. The true story is narrower, and better.https://www.youtube-nocookie.com/embed/DAKWM8ZGJ8c7202026-10-04T03:04:36+00:00yesno https://aussiescience.com/australian-science/black-box/https://aussiescience.com/thumbs/australian-science/black-box-1280.webpThe black box: David Warren's flight recorderEvery airliner carries two boxes that nobody hopes to open. Everyone calls them black boxes, but they're painted bright orange. And the idea for one key part, a recording of the voices in the cockpit, came from a fuel chemist in Melbourne in the 1950s. So how do you build a memory that survives a plane crash?https://www.youtube-nocookie.com/embed/7Kx2osE3UXI6792026-10-04T02:53:15+00:00yesno https://aussiescience.com/australian-science/cochlear-implant/https://aussiescience.com/thumbs/australian-science/cochlear-implant-1280.webpThe bionic ear: Graeme Clark's cochlear implantIf the part of your ear that actually hears is gone, how can you hear? For hundreds of thousands of people, the answer is a thin wire coiled inside the inner ear, talking to the nerve in electricity.https://www.youtube-nocookie.com/embed/MWmKxAY8vNM6822026-10-04T02:54:40+00:00yesno https://aussiescience.com/australian-science/penicillin/https://aussiescience.com/thumbs/australian-science/penicillin-1280.webpPenicillin: from Fleming's mould to a medicineBefore the nineteen-forties, a scratch could kill you. The first antibacterial drugs, the sulfa drugs, had only arrived in the mid-thirties, and hospitals were still full of people with blood poisoning from a cut. In 1928, a mould was seen killing bacteria on a plate in London.https://www.youtube-nocookie.com/embed/nMHRYz7O6z87282026-10-04T02:56:11+00:00yesno https://aussiescience.com/australian-science/ultrasound/https://aussiescience.com/thumbs/australian-science/ultrasound-1280.webpSeeing with sound: Australia's ultrasound pioneersHow do you make a picture of the inside of a body using nothing but sound? No knife, no X-rays, just a crystal pressed against the skin, listening for echoes. Australia didn't invent that idea.https://www.youtube-nocookie.com/embed/MVAdusrsAV47222026-10-04T02:57:39+00:00yesno https://aussiescience.com/australian-science/stomach-ulcers/https://aussiescience.com/thumbs/australian-science/stomach-ulcers-1280.webpThe doctor who drank bacteria: Marshall, Warren and ulcersHow do you prove that a germ causes a disease, when almost every expert is sure it can't? In 1984, a young doctor in Perth tried the most direct way there is. He drank a beaker of the bacteria. To see why, and why it still wasn't enough, start with what everyone knew about ulcers.https://www.youtube-nocookie.com/embed/Hldnkjd444A6962026-10-04T02:58:50+00:00yesno https://aussiescience.com/australian-science/hpv-vaccine/https://aussiescience.com/thumbs/australian-science/hpv-vaccine-1280.webpA vaccine against cancer: Frazer, Zhou and HPVYou can't catch cancer. Or so most of us assume. But almost every case of cervical cancer starts with a virus you catch, and can vaccinate against. In 1991, two scientists in Brisbane and their small team made the first version of the thing that vaccine is built on: the empty shell of a virus, with nothing inside.https://www.youtube-nocookie.com/embed/XJd7298suvg7272026-10-04T03:00:03+00:00yesno https://aussiescience.com/australian-science/spray-on-skin/https://aussiescience.com/thumbs/australian-science/spray-on-skin-1280.webpSpray-on skin: Fiona Wood and Marie StonerIf a burn takes most of your skin, where does the new skin come from? In Perth in the 1990s, a surgeon, Fiona Wood, and a scientist, Marie Stoner, started spraying a patient's own skin cells onto burns. The headlines called it spray-on skin. The real story is cleverer, and more careful, than the headline.https://www.youtube-nocookie.com/embed/WdNODt_HRew6742026-10-04T03:00:59+00:00yesno https://aussiescience.com/australian-science/polymer-banknotes/https://aussiescience.com/thumbs/australian-science/polymer-banknotes-1280.webpPlastic money: how Australia made polymer banknotesScrunch an Australian banknote into a ball, and it springs back. Try to tear it, and it's hard even to start. That's because it isn't paper; it's plastic. So why would a country print its money on plastic, and how could a clear little window stop a forger? The answer starts with a bakery.https://www.youtube-nocookie.com/embed/a_k3vP_gT646672026-10-04T03:01:54+00:00yesno https://aussiescience.com/australian-science/parkes/https://aussiescience.com/thumbs/australian-science/parkes-1280.webpThe Dish: how Parkes helped show the Moon landingIn July 1969, an estimated six hundred million people watched a man step onto the Moon. Most of that moonwalk reached them through a radio telescope in a paddock near Parkes, New South Wales. A famous film made it Parkes' show alone. The real story is shared.https://www.youtube-nocookie.com/embed/2OcxoOt610I6782026-10-04T02:51:11+00:00yesno https://aussiescience.com/maths-puzzles/zero/https://aussiescience.com/thumbs/maths-puzzles/zero-1280.webpWhat is zero, and why did it take so long to invent?Here's a puzzle. Write a 2 and a 5 side by side, and you've got 25. Now slip a little circle in between them, and you've got 205. You added nothing, and the number went up by 180. So how can nothing be worth a hundred and eighty? And if that little circle is so useful, why did people go so long without writing it down?https://www.youtube-nocookie.com/embed/qmKGz0kmMAU7112026-10-04T03:17:47+00:00yesno https://aussiescience.com/maths-puzzles/infinity/https://aussiescience.com/thumbs/maths-puzzles/infinity-1280.webpWhat is infinity, and can one infinity be bigger than another?Here's a puzzle. Which are there more of: the counting numbers, one, two, three, forever, or the square numbers, one, four, nine, sixteen? Surely the counting numbers, because most of them aren't squares. But pair them up: one with one, two with four, three with nine.https://www.youtube-nocookie.com/embed/ttzvQRexh1k6912026-10-04T03:19:45+00:00yesno https://aussiescience.com/maths-puzzles/point-nine-nine-nine/https://aussiescience.com/thumbs/maths-puzzles/point-nine-nine-nine-1280.webpDoes 0.999… really equal 1?Here's a puzzle. Write zero, a decimal point, and then nines, forever. Zero point nine recurring. Is that equal to one, or just a little bit less than one? Most people's gut says less. Hold on to your answer, because by the end you'll know exactly what those three little dots mean.https://www.youtube-nocookie.com/embed/_0xum-DuYyM6822026-10-04T04:07:21+00:00yesno https://aussiescience.com/maths-puzzles/monty-hall/https://aussiescience.com/thumbs/maths-puzzles/monty-hall-1280.webpShould you switch doors?You're on a game show, facing three closed doors. Behind one is a car, and behind the other two, goats. You pick door one. The host, who knows where the car is, opens door three: a goat. Do you want to switch to door two? Two doors, one car, so surely it's fifty-fifty. That's what most people think, and it's wrong.https://www.youtube-nocookie.com/embed/IMfGPAaQvFM6452026-10-04T04:09:20+00:00yesno https://aussiescience.com/maths-puzzles/birthday-paradox/https://aussiescience.com/thumbs/maths-puzzles/birthday-paradox-1280.webpWhy do 23 people probably share a birthday?Here's a bet. Walk into a room of 23 people, chosen at random, and offer even money that two of them share a birthday. Not your birthday, just any two people, same day and month. With 365 days to choose from, it sounds like a terrible bet. So should you take the bet at 23?https://www.youtube-nocookie.com/embed/NJe3-2XtrwU6822026-10-04T04:13:03+00:00yesno https://aussiescience.com/maths-puzzles/primes-and-rsa/https://aussiescience.com/thumbs/maths-puzzles/primes-and-rsa-1280.webpWhy do prime numbers keep your bank account safe?Last time we ended on a lock anyone can check but only you can close. To see how it works, start with a puzzle in two halves. First: what's 47 times 59? With a pencil, you'll have 2773 inside a minute. Second: two whole numbers, neither of them one, multiply to make 2773, so what are they?https://www.youtube-nocookie.com/embed/LND7q17alCU7132026-10-04T03:22:09+00:00yesno https://aussiescience.com/maths-puzzles/pi/https://aussiescience.com/thumbs/maths-puzzles/pi-1280.webpWhy does pi never end?Here's a puzzle you can do in the kitchen. Wrap a string once around a jar lid, then lay it straight across. It goes across three times, with a little left over. A coin or a bike wheel: three, and a bit. That bit starts point one four one five nine, and it doesn't stop. So why is it the same for every circle?https://www.youtube-nocookie.com/embed/YhVinl9DBAA7102026-10-04T04:05:58+00:00yesno https://aussiescience.com/maths-puzzles/zeno/https://aussiescience.com/thumbs/maths-puzzles/zeno-1280.webpHow did Achilles ever catch the tortoise?Here's a puzzle. Achilles, the fastest runner in Greek legend, races a tortoise and gives it a head start. Before he can pass it, he has to reach the spot where the tortoise started. But by then the tortoise has crawled a little further on. So he runs to that new spot, and it's moved again.https://www.youtube-nocookie.com/embed/aFNPGv_pIL86622026-10-04T04:05:03+00:00yesno https://aussiescience.com/maths-puzzles/graph-theory/https://aussiescience.com/thumbs/maths-puzzles/graph-theory-1280.webpHow did seven bridges start the maths behind Google Maps?Here's a puzzle. A river splits around an island, and seven bridges join the island, the two banks and a piece of land to the east. Can you go for a walk that crosses every bridge exactly once? Start anywhere, finish anywhere, no swimming.https://www.youtube-nocookie.com/embed/60pDlfw_M8U6582026-10-04T04:04:16+00:00yesno https://aussiescience.com/maths-puzzles/godel/https://aussiescience.com/thumbs/maths-puzzles/godel-1280.webpCan maths prove everything?Here's a puzzle. Read this sentence: this sentence is false. Is it true? If it's true, then what it says holds, so it's false. But if it's false, then what it says is right, so it's true. It flips forever and never lands. Hold on to that loop, because it unlocks a much bigger question. Can maths prove everything?https://www.youtube-nocookie.com/embed/8WUozW686aQ7162026-10-04T04:03:01+00:00yesno