# What is inside a smartphone?

An episode of [Science for Kids / Science's Not Boring: The Kids Science Podcast](https://invisiblenetwork.ai/podcast/1896928296), 22 Aug 2026, 14 min.

Audio: https://www.buzzsprout.com/2624612/episodes/19649857-what-is-inside-a-smartphone.mp3

Did you know the little rectangular screen in your pocket is actually a secret supercomputer? It is true! Join Mira and Finn on Science is Not Boring as they shrink down to microscopic size to explore exactly what is inside a smartphone! You won't believe the hidden science packed under the glass. Discover how a modern phone is millions of times more powerful than the massive computers NASA used to send the Apollo 11 astronauts to the Moon! We will uncover a microscopic city built from over 60 different elements—including real gold, silver, and superhero-sounding metals like neodymium! Learn how an unbelievable 19 billion tiny switches called transistors can fit on a computer chip the exact size of your fingernail. Find out why the glass screen is soaked in boiling molten salt, how your phone uses electricity to know exactly where your finger taps, and why recycling old electronics is so incredibly important for the planet. Grab your favorite gadget, get ready for some light-speed science, and let's crack open the ultimate technological mystery!

## Transcript

[0:46] SPEAKER_00: Welcome to Science is Not Boring by Kidopoly.com.
[0:50] SPEAKER_00: I'm Mira! And I'm Finn.
[0:53] SPEAKER_00: Before we dive into today's mystery, we have a very special shout-out.
[0:58] SPEAKER_00: A big hello to Abu and Bibi, two awesome sisters in North Carolina!
[1:04] SPEAKER_01: Yeah! We hear you two listen to all three of our shows in the car, at dinner, and even before bed.
[1:10] SPEAKER_00: Thank you so much for hanging out with us, Abu and Bibi.
[1:14] SPEAKER_00: This episode is dedicated to both of you.
[1:17] SPEAKER_01: Okay, so what mind-blowing science are we exploring today?
[1:20] SPEAKER_00: Well, Finn, look around you.
[1:23] SPEAKER_00: You probably have a small, shiny rectangle sitting near you right now.
[1:27] SPEAKER_00: It looks simple, but it is secretly a supercomputer.
[1:31] SPEAKER_00: Wait, you mean a smartphone?
[1:34] SPEAKER_00: Like the one we use to play games and watch videos.
[1:37] SPEAKER_00: Exactly.
[1:38] SPEAKER_00: We use them every single day.
[1:40] SPEAKER_00: But most people have no idea what is actually happening under the glass.
[1:44] SPEAKER_00: What's the big secret?
[1:46] SPEAKER_00: Here is the mind-blowing part.
[1:49] SPEAKER_00: A modern smartphone is over two million times more powerful than the computers that NASA used to send astronauts to the Moon.
[1:57] SPEAKER_01: No way! You're telling me the moon landing computer was weaker than a phone.
[2:02] SPEAKER_00: Way weaker.
[2:03] SPEAKER_00: Back in 1969, the Apollo 11 spacecraft made history using the Apollo guidance computer.
[2:10] SPEAKER_00: It was an absolute marvel of engineering for its time, but it weighed£70.
[2:15] SPEAKER_00: Haha,£70?
[2:18] SPEAKER_00: A phone weighs like six ounces.
[2:20] SPEAKER_00: Exactly.
[2:21] SPEAKER_00: So today we are cracking open the smartphone to find the tiny chips, sensors, and invisible radio waves that make it tick.
[2:29] SPEAKER_01: Okay, so if I shrink down like a bug and go inside my phone, what exactly am I looking at?
[2:35] SPEAKER_00: On the outside, it looks like a simple slab of glass and metal.
[2:39] SPEAKER_00: But inside, it looks like a futuristic, microscopic city.
[2:44] SPEAKER_00: A city?
[2:45] SPEAKER_00: Like with tiny roads and skyscrapers.
[2:47] SPEAKER_00: Kind of.
[2:48] SPEAKER_00: Instead of asphalt roads, it has highways made of pure copper wire to carry electricity.
[2:55] SPEAKER_00: And instead of buildings, it has microchips made of silicon.
[2:59] SPEAKER_00: But what is it all made of?
[3:01] SPEAKER_00: Where do the materials come from?
[3:03] SPEAKER_00: To build this tiny city, scientists have to dig into the earth.
[3:08] SPEAKER_00: A single smartphone uses around 62 different types of metals and elements.
[3:14] SPEAKER_01: Wait, out of the 118 known elements in the whole universe, over half of them are stuffed into my pocket.
[3:21] SPEAKER_00: Yep.
[3:22] SPEAKER_00: Think about that.
[3:23] SPEAKER_00: Most of the chemical elements known to humanity are working together in your hand right now.
[3:29] SPEAKER_00: That's insane! What kind of elements?
[3:32] SPEAKER_00: Well, there is actual gold, silver, and platinum making up the electrical connections.
[3:39] SPEAKER_00: But there are also rare earth metals that you've probably never heard of.
[3:43] SPEAKER_00: Like what?
[3:44] SPEAKER_00: Give me a weird one.
[3:45] SPEAKER_00: How about neodymium?
[3:47] SPEAKER_00: It is a super strong magnetic metal that makes your phone's tiny speakers vibrate to produce sound.
[3:54] unknown: Hahaha.
[3:55] SPEAKER_01: Neodymium.
[3:56] SPEAKER_01: That sounds like a metal from a superhero movie.
[3:58] SPEAKER_00: Or how about cobalt and lithium?
[4:01] SPEAKER_00: Those go into the battery to hold a powerful electrical charge.
[4:05] SPEAKER_01: So this one little gadget is basically a jigsaw puzzle made of pieces from all over the entire planet.
[4:10] SPEAKER_00: Exactly.
[4:12] SPEAKER_00: Ships and planes transport these raw materials across thousands of miles just to build the battery and the screen.
[4:20] SPEAKER_01: But how does the phone actually think?
[4:22] SPEAKER_01: Like, how does it know how to load a video game or take a picture?
[4:27] SPEAKER_00: That is all thanks to the brain of the phone, called the processor, or the microchip.
[4:33] SPEAKER_00: And inside that chip are microscopic switches called transistors.
[4:38] SPEAKER_01: Transistors?
[4:39] SPEAKER_01: Are they like tiny light switches that turn on and off?
[4:43] SPEAKER_00: That is exactly what they are.
[4:45] SPEAKER_00: They control the flow of electricity.
[4:47] SPEAKER_00: But they are so small you can't even see them with a regular microscope.
[4:52] SPEAKER_01: How tiny are we talking?
[4:54] SPEAKER_01: Like the size of a grain of sand.
[4:56] SPEAKER_00: Way, way smaller! The transistors inside a top-tier modern chip, like the Apple A17 Pro, are manufactured at a scale of just three nanometres.
[5:08] SPEAKER_01: Wait, how big is a nanometer?
[5:10] SPEAKER_01: I need a comparison.
[5:12] SPEAKER_00: Okay, pluck a single strand of your hair.
[5:15] SPEAKER_00: That hair is about 80,000 nanometres wide.
[5:19] SPEAKER_01: So you could fit thousands of these transistors on a single human hair.
[5:23] SPEAKER_00: Not just thousands, millions! In fact, on a single microchip the size of your fingernail, scientists pack in 19 billion transistors.
[5:34] SPEAKER_01: 19 billion?
[5:36] SPEAKER_01: That's more than double the entire human population on Earth sitting on my fingernail.
[5:41] SPEAKER_00: It is an absolute masterpiece of engineering.
[5:44] SPEAKER_00: Those 19 billion tiny switches flip on and off billions of times every single second to process math.
[5:54] SPEAKER_01: That makes my brain hurt.
[5:56] SPEAKER_01: How does that compare to the Apollo Moon computer?
[5:58] SPEAKER_00: The Apollo guidance computer only had about 4 kilobytes of memory.
[6:03] SPEAKER_00: A modern phone has up to 12 gigabytes of RAM.
[6:07] SPEAKER_01: Wait, what does that mean in numbers?
[6:09] SPEAKER_00: That means your phone has roughly 3 million times more memory.
[6:13] SPEAKER_00: The calculator app on your phone alone could run the entire Apollo mission thousands of times over.
[6:20] SPEAKER_01: Okay, the brain is massive.
[6:22] SPEAKER_01: But I want to know about the screen.
[6:24] SPEAKER_01: How does it know exactly where my thumb is when I tap it?
[6:28] SPEAKER_00: A lot of people think the screen works by sensing the pressure of your push.
[6:32] SPEAKER_00: But it's actually chemistry and electricity.
[6:35] SPEAKER_01: Wait, really?
[6:37] SPEAKER_00: The glass is electric.
[6:39] SPEAKER_00: Before it even becomes a screen, the glass is soaked in a bath of molten potassium salt.
[6:45] SPEAKER_00: Molten salt?
[6:46] SPEAKER_00: That sounds like a volcano.
[6:48] SPEAKER_00: Why soak it in hot salt?
[6:50] SPEAKER_00: It forces larger potassium atoms into the glass, which packs everything super tight when it cools.
[6:56] SPEAKER_00: That creates gorilla glass, making it incredibly tough and scratch-resistant.
[7:02] SPEAKER_01: Okay, so it's super tough.
[7:04] SPEAKER_01: But how does it feel my tap?
[7:06] SPEAKER_00: The glass is coated in a totally clear chemical compound called indium tin oxide.
[7:12] SPEAKER_00: This layer holds a tiny, continuous electrical charge across the whole screen.
[7:18] SPEAKER_01: Oh, and because human bodies conduct electricity, when I touch it, I steal a little bit of that charge.
[7:24] SPEAKER_00: Exactly! You change the electrical field.
[7:27] SPEAKER_00: The phone constantly measures that grid, and when the electricity dips in one specific spot, it knows exactly where your finger is.
[7:36] SPEAKER_01: That's why I can't use my phone when I'm wearing thick winter gloves.
[7:40] SPEAKER_01: The cloth blocks my electricity.
[7:42] SPEAKER_00: You got it! And that's not the only wild sensor.
[7:46] SPEAKER_00: What about when you turn your phone sideways to watch a video and the screen instantly flips?
[7:51] SPEAKER_00: Yeah.
[7:52] SPEAKER_00: How does it know gravity changed?
[7:54] SPEAKER_00: It uses an accelerometer.
[7:56] SPEAKER_00: Hidden inside the chip is a microscopic suspended mass made of silicon on tiny springs.
[8:03] SPEAKER_01: A microscopic mass on tiny springs?
[8:06] SPEAKER_00: Yes.
[8:06] SPEAKER_00: When you tilt the phone, gravity pulls on that tiny mass, causing it to move just a fraction of a hair's width.
[8:14] SPEAKER_00: The computer feels that movement and flips your screen.
[8:17] SPEAKER_01: That is the weirdest and coolest thing ever.
[8:21] SPEAKER_01: Microscopic suspended masses and electricity sensing salt glass.
[8:26] SPEAKER_01: The ingenuity is endless, and we haven't even talked about how it connects to the world.
[8:32] SPEAKER_01: Right, because a smartphone isn't just a computer, it's a communicator.
[8:37] SPEAKER_00: Exactly.
[8:39] SPEAKER_00: Hiding around the outer edges of the phone are antennas.
[8:42] SPEAKER_00: When you send a message, the phone translates your text into a radio wave.
[8:47] SPEAKER_01: And radio waves are a type of invisible light, right?
[8:51] SPEAKER_00: Yes.
[8:52] SPEAKER_00: The phone blasts that radio wave out at the speed of light, 186,000 miles per second, to a cell tower.
[9:01] SPEAKER_01: 186,000 miles per second?
[9:04] SPEAKER_01: That's why I can talk to someone in Australia and hear them instantly.
[9:09] SPEAKER_01: Exactly.
[9:10] SPEAKER_00: You are holding a light-speed laser communicator in your pocket.
[9:14] SPEAKER_00: But Finn, all this amazing technology has a huge impact on our planet.
[9:19] SPEAKER_01: Because we have to mine all those 62 elements from the Earth, right?
[9:24] SPEAKER_00: Right.
[9:25] SPEAKER_00: And humans manufacture about 1.3 billion new smartphones every single year.
[9:31] SPEAKER_00: That takes a massive toll on the environment.
[9:34] SPEAKER_00: 1.3 billion a year?
[9:37] SPEAKER_00: What happens to the old ones?
[9:39] SPEAKER_00: That leads to my favourite fun fact.
[9:41] SPEAKER_00: Because there are tiny amounts of real gold used in the circuit boards, our old phones are extremely valuable.
[9:49] SPEAKER_01: Wait, are you saying there is actual treasure in my junk drawer?
[9:53] SPEAKER_00: Yes.
[9:54] SPEAKER_00: Listen to this statistic.
[9:56] SPEAKER_00: One ton of recycled smartphones contains 300 times more gold than a ton of actual gold ore dug straight out of a mine.
[10:05] SPEAKER_01: 300 times more?
[10:07] SPEAKER_01: We shouldn't be mining the ground.
[10:09] SPEAKER_01: We should just be mining old phones.
[10:12] SPEAKER_00: Exactly! That's called urban mining.
[10:15] SPEAKER_00: And it's why recycling your old electronics is so incredibly important for the future of science.
[10:20] SPEAKER_00: Alright, Finn, it's my favourite time of the show.
[10:23] SPEAKER_00: It is quiz time!
[10:26] SPEAKER_01: Okay, I'm ready.
[10:27] SPEAKER_01: Hit me with those super smart questions.
[10:30] SPEAKER_00: First question.
[10:31] SPEAKER_00: How many tiny transistors can fit on a top-tier modern smartphone microchip?
[10:40] SPEAKER_00: Next one.
[10:42] SPEAKER_00: The smartphone is millions of times more powerful than the computer that sent Watt famous 1969 mission to the moon?
[10:54] SPEAKER_00: Question 3.
[10:56] SPEAKER_00: Roughly how many different types of metals and elements are used to build a single smartphone?
[11:06] SPEAKER_00: Here's number four.
[11:07] SPEAKER_00: What super hot liquid is the glass screen soaked in to make it super strong and scratch resistant?
[11:18] SPEAKER_00: Last question.
[11:19] SPEAKER_00: How does the screen actually know exactly where your finger touches it?
[11:27] SPEAKER_00: Great job! Let's see how you did.
[11:30] SPEAKER_00: The first answer is a modern chip has an unbelievable 19 billion transistors.
[11:37] SPEAKER_00: For question two, it was the Apollo 11 mission.
[11:42] SPEAKER_00: The answer to question 3 is around 62 different elements.
[11:48] SPEAKER_00: For question 4, it is soaked in a bath of molten potassium salt.
[11:53] SPEAKER_00: And the final answer is, it senses a drop in its own electrical field.
[11:59] SPEAKER_00: Hahaha!
[12:00] SPEAKER_01: I got them all! I am basically a walking supercomputer now.
[12:05] SPEAKER_00: You sure are! But seriously, this technology is incredible.
[12:10] SPEAKER_01: I am never, ever looking at my phone the same way again.
[12:14] SPEAKER_01: It's basically an alien artifact in my pocket.
[12:17] SPEAKER_00: I know! Between the 19 billion tiny switches, the microscopic suspended masses, and the light-speed radio waves.
[12:26] SPEAKER_00: Science really is everywhere.
[12:28] SPEAKER_01: And to think the astronauts went to the moon with four kilobytes of memory.
[12:32] SPEAKER_01: I'm going to appreciate my games a lot more now.
[12:36] SPEAKER_00: If you had fun exploring the microscopic city inside your phone today, please leave us a five-star review.
[12:42] SPEAKER_01: Yeah, just scroll down on your podcast app and tap those five stars.
[12:46] SPEAKER_01: And when you do, think of those 19 billion transistors working hard to process it.
[12:52] SPEAKER_00: Oh, and don't forget to check out our site, kidopoly.com.
[12:56] SPEAKER_00: We've got tons of fun learning games and activities there.
[13:00] SPEAKER_01: It's the best place to keep the science going.
[13:02] SPEAKER_01: And if you want a shout out on the show or just want to say hi, email us at hello at kidopoly.com.
[13:09] SPEAKER_00: We love hearing from you.
[13:11] SPEAKER_01: Thanks for exploring with us today.
[13:13] SPEAKER_01: See you next time on Science is Not Boring.
[13:17] SPEAKER_01: Bye, everyone!

Shows are listed from Apple Podcasts' charts and directory, and Podcast Index where it is used. Every show and episode belongs to its publisher and plays from the publisher's own feed; this site hosts none of them.