# What is a skyscraper?

An episode of [Science for Kids / Science's Not Boring: The Kids Science Podcast](https://invisiblenetwork.ai/podcast/1896928296), 3 Sep 2026, 15 min.

Audio: https://www.buzzsprout.com/2624612/episodes/19709923-what-is-a-skyscraper.mp3

Have you ever wondered how super-tall buildings and massive bridges stand up without falling down? Join Mira and Finn as they uncover the invisible forces trying to knock down our cities—like sneaky gravity, fierce wind, and powerful earthquakes! Discover how clever engineers fight back using the brilliant science of shapes and materials. Did you know the strongest shape in the engineering world is the trusty triangle? Or that the Burj Khalifa in Dubai is so incredibly high up, you can ride an elevator to the top to time-travel and watch the exact same sunset twice?! Get ready for some truly mind-blowing engineering secrets! You will learn about a giant 660-tonne golden ball swinging inside Taipei 101 that stops the skyscraper from snapping during huge storms. Plus, find out how a massive Japanese suspension bridge survived a monster earthquake that stretched it a whole meter longer! With enough metal wire to wrap around the Earth seven times and roots deeper than a swimming pool, these mega-structures are basically real-life superheroes. Tune in to explore the awesome physics and geometry that hold our world together!

## Transcript

[0:00] SPEAKER_00: Welcome to Science Is Not Boring by Kidopoly.com.
[0:04] SPEAKER_00: I'm Mira! And I'm Finn.
[0:06] SPEAKER_00: Finn, did you know there is a building so incredibly tall that if you stand at the bottom and watch the sun set over the horizon, you can immediately jump into an elevator, ride to the very top, and watch the exact same sunset all over again.
[0:23] SPEAKER_00: Wait, what?
[0:25] SPEAKER_00: They literally time travel to a second sunset.
[0:28] SPEAKER_00: Sort of.
[0:29] SPEAKER_00: The people on the top floors see the sunset about three whole minutes after the people on the ground.
[0:36] SPEAKER_00: It is so high up that it actually peaks over the curve of the earth.
[0:40] SPEAKER_00: That is bonkers.
[0:42] SPEAKER_00: What building is it?
[0:43] SPEAKER_00: It's the Burj Khalifa in Dubai.
[0:46] SPEAKER_00: And reading about it got me thinking, how in the world do these giant skyscrapers and massive bridges stand up without falling down?
[0:55] SPEAKER_00: Yeah, I mean, some of them scrape the clouds, and bridges leap across whole rivers with thousands of cars driving on them every day.
[1:03] SPEAKER_00: Today we are discovering the clever science of shapes, forces, and materials.
[1:08] SPEAKER_00: We'll find out how engineers manage to build higher and further than ever before, defying nature itself.
[1:15] SPEAKER_00: I bet they use magic or superglue.
[1:18] SPEAKER_00: Really, really strong superglue that smells like marshmallows.
[1:23] SPEAKER_00: Even better, Finn.
[1:24] SPEAKER_00: They use science, physics, and brilliant geometry.
[1:28] SPEAKER_00: From giant golden swinging balls to deep concrete roots, the secrets inside our cities are going to blow your mind.
[1:37] SPEAKER_00: Let's get into it! Before we look at massive buildings, we need to understand the invisible enemies that engineers have to fight every single day.
[1:45] SPEAKER_00: Invisible enemies, like ghosts.
[1:48] SPEAKER_00: I knew it.
[1:49] SPEAKER_00: I always suspected ghosts were trying to knock over my block towers.
[1:54] SPEAKER_00: No, not ghosts.
[1:55] SPEAKER_00: I'm talking about forces.
[1:58] SPEAKER_00: Gravity is constantly pulling things down toward the centre of the earth.
[2:03] SPEAKER_00: Wind is constantly pushing things over from the side.
[2:06] SPEAKER_00: And sometimes earthquakes violently shake the ground beneath us.
[2:11] SPEAKER_00: Okay, so how do you fight wind and gravity?
[2:14] SPEAKER_00: You can't just punch a gust of wind.
[2:16] SPEAKER_00: No, but you can build smart.
[2:19] SPEAKER_00: When engineers design a bridge or a skyscraper, they have to think about two main forces acting on the structure: compression and tension.
[2:29] SPEAKER_00: Compression?
[2:30] SPEAKER_00: Like squishing something together.
[2:32] SPEAKER_00: Exactly.
[2:33] SPEAKER_00: Compression is a squishing or pushing force.
[2:36] SPEAKER_00: Imagine stepping on an empty soda can until it crushes.
[2:40] SPEAKER_00: That's compression.
[2:42] SPEAKER_00: But tension is the exact opposite.
[2:45] SPEAKER_00: It's a pulling or stretching force.
[2:48] SPEAKER_00: Oh, like pulling on a heavy rubber band until it snaps.
[2:51] SPEAKER_00: Spot on! When a heavy gust of wind pushes on a tall building, it creates tension on the side it's blowing against, trying to stretch and snap the building.
[3:03] SPEAKER_00: But it creates compression on the opposite side.
[3:06] SPEAKER_00: That's why materials really matter.
[3:08] SPEAKER_00: Do they use concrete or steel?
[3:11] SPEAKER_00: Both.
[3:12] SPEAKER_00: Concrete is great at handling the squishing force of compression, but it's terrible at stretching.
[3:19] SPEAKER_00: Steel, on the other hand, is amazing at handling the stretching force of tension.
[3:24] SPEAKER_00: So they mix them together into reinforced concrete.
[3:28] SPEAKER_00: Oh, so it has the superpower of both materials.
[3:31] SPEAKER_00: Precisely.
[3:32] SPEAKER_00: But the materials need the right shape to distribute those forces safely.
[3:38] SPEAKER_00: And the ultimate superhero of all shapes in the engineering world is the triangle.
[3:44] SPEAKER_00: A triangle, not a square.
[3:46] SPEAKER_00: Squares look so solid though, like a big strong fortress.
[3:51] SPEAKER_00: That's what a lot of people think.
[3:53] SPEAKER_00: But if you build a square out of plastic straws and push on one of its top corners, what happens?
[3:59] SPEAKER_00: Um, it squishes.
[4:01] SPEAKER_00: It sort of leans over and turns into a flat diamond shape.
[4:05] SPEAKER_00: Exactly.
[4:06] SPEAKER_00: But if you build a triangle out of those same straws and push on the top point, it doesn't budge.
[4:13] SPEAKER_00: You cannot deform a triangle without actually breaking one of its sides.
[4:17] SPEAKER_00: Whoa! Why is it so incredibly strong?
[4:20] SPEAKER_00: Because a triangle distributes the force perfectly.
[4:24] SPEAKER_00: When you push on that top point, the weight travels evenly down the two angled sides and spreads out across the strong bottom base.
[4:33] SPEAKER_00: So it shares the heavy load with all of its parts.
[4:36] SPEAKER_00: That is so clever.
[4:38] SPEAKER_00: Right! That's why if you look at a metal bridge or a tall construction crane, or even the wooden frame holding up the roof of your house, you will see thousands of triangles hiding in plain sight.
[4:51] SPEAKER_00: Now that we know about shapes and forces, let's talk about the biggest, heaviest things humans have ever built.
[4:58] SPEAKER_00: Back to that building from earlier, the Burj Khalifa in Dubai.
[5:03] SPEAKER_00: The Sunset Time Travel One.
[5:05] SPEAKER_00: Just how tall is it?
[5:07] SPEAKER_00: I need numbers.
[5:08] SPEAKER_00: It is 828 metres tall.
[5:12] SPEAKER_00: That is over 2,700 feet.
[5:16] SPEAKER_00: To picture that, imagine taking 150 full-grown giraffes and stacking them all on top of each other.
[5:25] SPEAKER_00: That is a lot of long necks.
[5:27] SPEAKER_00: Wait, if it's that tall, how heavy is it?
[5:30] SPEAKER_00: The entire building weighs about 450,000 tonnes.
[5:35] SPEAKER_00: That is roughly the weight of a hundred thousand elephants.
[5:39] SPEAKER_00: Hold on a second.
[5:41] SPEAKER_00: Dubai is in the Middle East, right?
[5:42] SPEAKER_00: It's surrounded by a desert.
[5:44] SPEAKER_00: Doesn't a building that huge and heavy just sink straight down into the soft sand?
[5:49] SPEAKER_00: That was the exact problem engineers faced.
[5:52] SPEAKER_00: If you just put a heavy box on sand, it sinks like a rock in quicksand.
[5:58] SPEAKER_00: They couldn't do that.
[5:59] SPEAKER_00: So what did they do?
[6:00] SPEAKER_00: Build it on a giant metal plate?
[6:03] SPEAKER_00: Almost.
[6:04] SPEAKER_00: Underneath the ground, engineers hammered 192 giant concrete legs, called piles, deep into the earth.
[6:12] SPEAKER_00: How deep?
[6:14] SPEAKER_00: Like a swimming pool deep?
[6:16] SPEAKER_00: Way deeper.
[6:17] SPEAKER_00: Each individual concrete pile is 1.5 metres thick and buried over 50 metres or 164 feet down into the soil.
[6:28] SPEAKER_00: 164 feet into the sand?
[6:32] SPEAKER_00: Yes, because they go so deep, the sides of all 192 concrete legs create a massive amount of friction against the packed sand and rock.
[6:42] SPEAKER_00: That friction grips the legs tight and holds up the massive weight of the tower.
[6:48] SPEAKER_00: Wow, so it has giant concrete roots, like a super heavy, unbreakable tree.
[6:54] SPEAKER_00: Exactly! And to stop the extreme desert winds from knocking it over, they didn't just build a giant flat wall.
[7:02] SPEAKER_00: They built the tower in a special Y shape, like a three-pointed star.
[7:06] SPEAKER_00: Why a Y-shape?
[7:08] SPEAKER_00: Does it look cool?
[7:10] SPEAKER_00: It does look cool, but it's called a buttressed core.
[7:14] SPEAKER_00: Because it has three wings pointing outward, the shape physically slices through the wind from any direction, preventing the building from catching the wind like a sail and wobbling.
[7:25] SPEAKER_00: But what if the wind is really, really bad?
[7:29] SPEAKER_00: Like a hurricane or a typhoon?
[7:32] SPEAKER_00: Or what if the ground violently shakes in an earthquake?
[7:35] SPEAKER_00: Can a tall building survive that?
[7:37] SPEAKER_00: I am so glad you asked, because we are travelling across the world to Taiwan to visit a skyscraper called Taipei 101.
[7:47] SPEAKER_00: Let me guess.
[7:48] SPEAKER_00: It has 101 floors?
[7:51] SPEAKER_00: You guessed it! It's 508 metres tall, which is over 1600 feet.
[7:57] SPEAKER_00: And because of where it's located, it gets hit by intense typhoons and massive earthquakes all the time.
[8:05] SPEAKER_00: Yikes! I would not want to be drinking a glass of milk on the 100th floor during an earthquake.
[8:10] SPEAKER_00: The whole building would whip back and forth.
[8:13] SPEAKER_00: You would think so, but the engineers gave Taipe A101 a mind-blowing secret weapon.
[8:20] SPEAKER_00: Right in the middle of the building, hanging in an open space between the 87th and 92nd floors, is a giant golden ball.
[8:30] SPEAKER_00: A giant ball?
[8:32] SPEAKER_00: Like a wrecking ball inside a fancy skyscraper.
[8:36] SPEAKER_00: Kind of.
[8:37] SPEAKER_00: It's called a tuned mass damper.
[8:40] SPEAKER_00: It's a massive, solid steel sphere that weighs 660 tonnes.
[8:46] SPEAKER_00: That is as heavy as an entire herd of a hundred elephants just hanging from the ceiling indoors.
[8:53] SPEAKER_00: Wait, how big is this thing?
[8:56] SPEAKER_00: Can people see it?
[8:57] SPEAKER_00: Yes, visitors can actually walk around it.
[9:00] SPEAKER_00: It's 18 feet across and it hangs suspended by 92 incredibly thick steel cables.
[9:08] SPEAKER_00: But what does a giant hanging metal ball actually do when an earthquake hits?
[9:13] SPEAKER_00: When a strong wind or an earthquake pushes the building to the right, the giant 660-ton ball naturally swings to the left.
[9:23] SPEAKER_00: It acts like a giant counterweight to counteract the push of nature.
[9:28] SPEAKER_00: Oh, I get it.
[9:29] SPEAKER_00: It pulls the building back to the centre before it can tip too far.
[9:33] SPEAKER_00: Exactly.
[9:34] SPEAKER_00: The heavy ball absorbs the kinetic energy of the wind and the shaking.
[9:39] SPEAKER_00: It actually reduces the building swaying by up to 40%.
[9:44] SPEAKER_00: It keeps the whole skyscraper standing tall and steady.
[9:48] SPEAKER_00: And it's not just tall buildings that have to fight these intense forces.
[9:52] SPEAKER_00: Giant bridges have to do it too.
[9:54] SPEAKER_00: Let's look at the Akashi Kaikyo Bridge in Japan.
[9:58] SPEAKER_00: Is it a big bridge?
[10:00] SPEAKER_00: Like Golden Gate Bridge big?
[10:02] SPEAKER_00: It's way bigger! It's a massive suspension bridge that is nearly 4,000 metres long in total.
[10:09] SPEAKER_00: But the craziest part of its story is what happened while it was being built in the year 1995.
[10:16] SPEAKER_00: Oh no, what happened?
[10:18] SPEAKER_00: Did a ship crash into it?
[10:20] SPEAKER_00: Worse.
[10:21] SPEAKER_00: A massive earthquake struck.
[10:22] SPEAKER_00: The Great Hanshin earthquake.
[10:25] SPEAKER_00: The bridge's two giant metal towers had already been built standing in the deep water, but the roadway wasn't attached yet.
[10:34] SPEAKER_00: Did they fall over into the ocean?
[10:36] SPEAKER_00: No! The engineering was so spectacular that they stayed up.
[10:41] SPEAKER_00: But the earthquake actually moved the tectonic plates underneath them.
[10:45] SPEAKER_00: It physically pushed the two towers one whole metre further apart.
[10:50] unknown: Haha!
[10:51] SPEAKER_00: Wait, so the earthquake just made the bridge a metre longer?
[10:55] SPEAKER_00: Yes.
[10:56] SPEAKER_00: The engineers didn't have to start over.
[10:58] SPEAKER_00: They just had to recalculate their math and make the main cables a tiny bit longer to reach across the new gap.
[11:05] SPEAKER_00: Speaking of those cables, they are an engineering marvel.
[11:10] SPEAKER_00: What's so special about them?
[11:11] SPEAKER_00: Are they just thick ropes?
[11:13] SPEAKER_00: They are steel cables holding up the entire heavy roadway, and the main cables are 1.12 metres thick.
[11:21] SPEAKER_00: That's wider than a hula hoop.
[11:23] SPEAKER_00: Wow.
[11:24] SPEAKER_00: Do they just pour one giant thick piece of metal to make it?
[11:28] SPEAKER_00: No, a solid piece of metal that thick would snap when the bridge flexes in the wind.
[11:34] SPEAKER_00: They need the metal to be incredibly strong but also flexible.
[11:39] SPEAKER_00: So they use thousands of tiny wires.
[11:42] SPEAKER_00: Inside each giant cable, there are 36,830 individual metal wires tightly packed together.
[11:51] SPEAKER_00: 36,000?
[11:52] SPEAKER_00: That's a lot of wire.
[11:54] SPEAKER_00: How did they even make that?
[11:56] SPEAKER_00: They used a special spinning machine that travelled back and forth across the water, pulling strings of wire over the towers hundreds and hundreds of times.
[12:06] SPEAKER_00: That sounds like a giant metal spider making a super strong web.
[12:10] SPEAKER_00: That's exactly what it looks like.
[12:12] SPEAKER_00: And it gets crazier.
[12:14] SPEAKER_00: If you took all those individual wires from that one bridge and laid them end to end, they would stretch for 300,000 kilometres.
[12:24] SPEAKER_00: How far is that?
[12:25] SPEAKER_00: That is enough wire to wrap around the entire earth seven and a half times, all holding up one single bridge.
[12:33] SPEAKER_00: Alright, Finn, quiz time.
[12:35] SPEAKER_00: Okay, I'm ready.
[12:37] SPEAKER_00: First question.
[12:38] SPEAKER_00: How deep are the concrete piles buried under the Burj Khalifa?
[12:45] SPEAKER_00: Next one.
[12:47] SPEAKER_00: What shape is considered the strongest in engineering because it won't deform?
[12:55] SPEAKER_00: Question three.
[12:57] SPEAKER_00: How much does the giant golden tuned mass damper inside Type A101 weigh?
[13:06] SPEAKER_00: Here's number four.
[13:07] SPEAKER_00: Between which two floors does that giant golden ball hang?
[13:15] SPEAKER_00: Last question.
[13:17] SPEAKER_00: How many times could the wires from the Japanese suspension bridge wrap around the earth?
[13:26] SPEAKER_00: Great job! Let's see how you did.
[13:29] SPEAKER_00: The first answer is the piles are buried 50 metres or 164 feet deep.
[13:36] SPEAKER_00: For question 2, the stronger shape is the triangle.
[13:41] SPEAKER_00: Number 3, the answer is the ball weighs 660 tonnes.
[13:46] SPEAKER_00: Question 4, it hangs between the 87th and 92nd floors.
[13:52] SPEAKER_00: And the final answer is the wires could wrap around the earth 7.5 times.
[13:58] SPEAKER_00: I am never going to look at a tall building or a bridge the same way again.
[14:03] SPEAKER_00: Triangles and giant swinging balls of steel are hiding everywhere, right above our heads.
[14:10] SPEAKER_00: Science really is everywhere, Finn.
[14:13] SPEAKER_00: It's holding up our whole world, making sure we are safe when the wind blows and the ground shakes.
[14:20] SPEAKER_00: Engineering is basically a real-life superpower.
[14:23] SPEAKER_00: If you guys like learning about these awesome megastructures with us, please leave us a five-star review.
[14:30] SPEAKER_00: Yes.
[14:30] SPEAKER_00: Just like a strong foundation holds up a skyscraper, your five-star reviews hold up our show.
[14:37] SPEAKER_00: Just scroll down on your app and tap those five stars.
[14:40] SPEAKER_00: Oh, and don't forget to check out our site, kidopoly.com.
[14:44] SPEAKER_00: We've got tons of fun learning games and awesome science activities there.
[14:49] SPEAKER_00: It's true! Our site kidopoly.com is packed with cool stuff to explore.
[14:54] SPEAKER_00: And if you want to shout out on the show or just want to say hi, email us at hello at kidopoly.com.
[15:01] SPEAKER_00: We would love to hear from you and put your name in an episode.
[15:04] SPEAKER_00: Thanks for exploring with us today, everyone.
[15:07] SPEAKER_00: See you next time on Science Is Not Boring.
[15:11] SPEAKER_00: Bye, everyone.
[15:12] SPEAKER_00: Keep building cool stuff.

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