The Physics of Ancient Weaponry

Ancient weapon engineers—working without advanced mathematics, computers, or even basic calculus—created devices so effective they changed the course of history and embodied physical principles we still use today. They didn't need venture capital or TED talks. They needed results.

Listen to this fascinating Heliox podcast episode on ancient siege weapons, and you immediately notice something striking: engineers from Greece and Rome were applying sophisticated physics principles centuries before Newton or Leibniz formalized them.

They understood energy conversion without differential equations. They grasped leverage, force multiplication, and trajectory optimization through systematic observation and refinement. What's more impressive—they actually built functional machines that worked reliably in high-stakes environments. ... continue reading the article

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Transcript

0:25

This is Heliox, where evidence meets empathy. Independent, moderated, timely, deep, gentle, clinical, global, and community conversations about things that matter. Breathe easy. We go deep and lightly surface the big ideas. Welcome to the Deep Dive. Today, we're launching ourselves headfirst into the fascinating physics that powered some of the ancient world's most, well, formidable weaponry. That's right. We're dug in catapults, siege engines, all that good stuff. Exactly. And this came from you, our listener. You were curious to get a solid, quick understanding of these historical engineering marvels. Yeah. And we've gathered some really interesting sources for this deep dive. We've got articles looking at how they evolved, the mechanics, the science behind them. Our goal really is to unpack how these machines actually worked. You know, what physics principles were they using, maybe without even knowing the terms? And why were they so incredibly effective? It's like a shortcut to understanding this amazing bit of history and engineering without wading through tons of diagrams and dense texts yourself. So let's dive in. How did ancient folks without computers or modern labs pull off these feats of weapon engineering? What's the secret sauce? Okay, catapults. Instantly makes you think of castles under siege, right? Rocks flying. Definitely. But our sources show they weren't just invented overnight. It was a process. Started in Greece, was it? Ancient Greece, yeah. Yeah. Back in the 4th century BCE. And then the idea spread. The Romans, being the Romans, really took it and ran with it. They refined the designs massively. And by the Middle Ages, these things were everywhere in warfare. Huge siege engines, yeah. Became a staple. And not just one kind of catapult either. Our sources mention a few key types. Oh, yeah. Several variations. Yeah, the ballista, think of it like a giant crossbow. Really precise, launching big arrows or bolts. It worked using torsion. Torsion. Twisting force. Exactly. Then there was the manganel. Also used torsion. But it was more about lobbing stones in a high arc. Less precision, maybe more brute force for walls. And the big one, the trebuchet, that used a counterweight. That's the one. A heavy counterweight falling is what powered it. Let them throw much heavier stuff much further. Use gravitational potential energy. Total driven mechanism. There is also this caraballista. Sounds like mobile artillery. It basically was a ballista mounted on a cart dating way back to the 5th century BC. Needed two guys. One cranked it to store energy. The other aimed and fired these huge bolts. Amazing. Portable power. And the power to weight ratio was apparently pretty good. The Romans had like 55 per legion. shows you they were thinking tactically about mobility early on. And this Polybolos? Yeah. A repeating aero machine. Sounds like science fiction for the time, doesn't it? But yeah, 3rd century BC Greece. It had a chain-link drive, a windlass for power, and it could auto-cock and fire from a magazine of about 15 arrows. An early machine gun, essentially. Yeah. Incredible automation. Okay, so all these machines, they're chucking things with serious power. It fundamentally comes down to stored energy, right? That's the absolute core principle. You store potential energy in some way, and then you convert it really quickly into kinetic energy, the energy of motion, which flings the projectile. Like pulling back a rubber band. Exactly like that. Same physics. So let's break down how they stored it. Torsion-first ballistas, mangonels, that twisting, how did that work? Right. Imagine bundles of rope, usually made from really strong elastic stuff like animal sinew, or even hair, packed tightly into a frame. Then you twist these bundles using levers. Okay. The more you twist, the more potential energy gets stored in those stretched and twisted fibers. They desperately want to untwist back to their original state. And the strength of the rope, how much you twist it, that all affects the power. Absolutely. And the length of the throwing arm matters too. A longer arm attached to that torsion spring can move faster at the tip when it's released. So when they let go, bang, all that stored energy becomes motion. Our sources mention Roman Meliste, wooden frames, twisted sinew in a metal box, hitting targets 500 yards away. That's wild. It really speaks to their craftsmanship and material science, even if it was empirical. They knew what worked. And they had smaller ones, too, the Scorpio. Yeah, the Scorpio is more like field artillery. Still use torsion springs, they call them Tormenta, but smaller, maybe 100 meter range. Yeah. Much more portable. And they had manuals for these, with formulas. Apparently so. Formulas for spring sizes based on the bolt weight, that shows a level of standardization and applied mathematics that's really quite sophisticated for the time. Think about needing to supply spare parts for legions across the empire. Okay, then the other big method, gravitational potential energy. That's the trebuchet's domain. Right. Completely different concept. You lift a massive weight off in a box filled with stones or lead up high. Storing energy because of its height and reach. Exactly. Gravitational potential energy. When you release it, gravity pulls the weight down hard and fast. And that falling motion swings the long throwing arm. Correct. The counterweight falls, the arm pivots, and the other end, the one with a sling holding the projectile, whips around at incredible speed. So heavier weight, higher drop, more power. Precisely. And again, the length of the throwing arm is crucial. It acts as a lever, multiplying the speed at the sling end. Engineers could tweak the counterweight, the release point, the sling length, all to hit different targets at different ranges. So they were fine-tuning these massive things on the battlefield. Based on experience, yeah. Trial and error, observation, kind of early applied science, really. But it's not just raw power, is it? You've got to actually hit something. Trajectory, angles. That must have been critical. Oh, absolutely fundamental. The angle you launch at determines how far the projectile goes and how high it flies. Like in physics class, 45 degrees for maximum range. In a perfect vacuum, yes. But the real world, you've got air resistance, wind, maybe you're shooting uphill or downhill. Things get complicated. So when our sources say trebuchets and mangonels usually fired between, say, 40 and 50 degrees, that was them compensating. Exactly. They'd adjust the angle based on how far away the target was, how heavy the projectile was, maybe how high the wall they needed to clear was. It was practical ballistics figured out through practice. And leverage seems to be a recurring theme here. The throwing arm itself is a lever, right? Yes, a very important one. You have the fulcrum, which is the pivot point. Then the effort arm, where the force comes from, like the counterweight or the torsion spring connection. And the load arm, the part that actually moves the projectile. So by playing with the lengths of those arms, you get mechanical advantage. For trebuchet, making the counterweight side of the arm shorter than the projectile side means the projectile end travels much greater distance, and therefore much faster, for the same pivot angle. Training the distance the force is applied for speed and distance of the projectile. Precisely. Less input force needed to launch something heavy, or launching something faster and further with the available force. Smart engineering. What about air resistance? Did they just ignore it, or did they kind of figure it out? They definitely didn't have the math for aerodynamics, but they clearly had an intuitive grasp. The sources mentioned lobbing lighter things like pots of burning pitch or even diseased bodies at higher angles. To maximize flight time, get more range, or just let them rain down for longer. Whereas heavy stones meant to smash walls, they'd often fire at lower, flatter angles for maximum impact speed and force, minimizing the time air resistance had to slow them down. So they matched the launch style to the projectile and the goal. Seems like it. And the shape, you know, a roughly round stone, is reasonably aerodynamic for a simple projectile. They weren't designing missiles, but they understood the basics through results. We're talking a lot about the physics, but these machines, the psychological impact must have been huge. Oh, immense. Just seeing one of these massive engines being assembled outside your walls would be terrifying. The noise, the ground shaking when it fired. I didn't mention what it was throwing. Right. Huge rocks smashing into fortifications, flaming projectiles setting things ablaze, causing panic. And yeah, the really grim stuff. Biological warfare with carcasses. It's brutal. but effective in spreading disease and terror. Even just forcing defenders to constantly hide from long-range bombardment had a massive tactical effect. It pinned them down. Okay, so catapults were obviously central, but ancient military engineering had other tricks up its sleeve, didn't it? Our sources mention some other wild stuff. Definitely. The Claw of Archimedes. That thing sounds like something out of myth. What was it exactly? Picture a huge crane-like beam on the walls of Syracuse during the Roman siege. It had a massive grappling hook, a claw attached by ropes and pulleys. And they used it to. To grab Roman ships that got too close to the walls. They'd lift the front of the ship right out of the water, sometimes capsizing it or dropping it suddenly. Imagine being a Roman sailor seeing ships just lifted into the air. Terrifying. No wonder they thought the gods were involved. Exactly. Huge psychological weapon. Apparently defended the city for three years. Brilliant use of leverage again. And then there were giant warships, like truly enormous. Yeah, one Egyptian example from the second century B.C., the numbers are staggering. 130 meters long, 18 wide, a crew of over 7,000 sailors, rowers, Marines. Built in the desert, how? Mind-boggling logistics. Probably Lebanese timber somehow transported and assembled. Just the scale of it marks it as one of the largest war machines ever. And Archimedes, him again, supposedly designed a warship that could throw 55-kilogram stones over 180 meters. So floating artillery platforms, too. Okay, one more. Greek fire. This sounds nasty. Oh, it was. A Byzantine naval weapon, basically ancient napalm. It was a liquid compound shot from tubes that would ignite on contactor as it was launched. And it burned on water. That was the terrifying part. It created floating barriers of fire, devastating for wooden ships. And supposedly, water didn't put it out. You needed sand, vinegar, or, well, urine. And they kept the recipe secret. Top secret. We still don't know the exact ingredients. probably petroleum-based, maybe pitch, sulfur, lime. Some speculate quicklime, which reacts with water, might have been involved. Shows a real understanding of chemical properties for warfare. It's just incredible thinking about these ancient engineers. No formal physics degrees, no CAD software. But they mastered force, energy, trajectory through sheer ingenuity, observation, trial, and error. It's really a testament to human problem solving. And you see echoes today, don't you? All the time. Roller coasters playing with potential and kinetic energy, that's a trebuchet principle. Aircraft carrier catapults, okay, different tech, but same idea of stored energy release. Even robotic arms use leverage and sometimes torsion principles. These fundamental physics concepts just don't change. Nope. And the Romans, as our sources point out, were masters at refining and applying these. They're versions of the ballista, the Scorpio. They focus on efficiency, accuracy, even mobility. Their engineering skill was absolutely tied to their military dominance. Those manuals for the Scorpio just underline that systematic approach. So wrapping this deep dive up, we've really seen how ancient weapon makers were, in effect, applied physicists. They understood force, energy transfer, angles, leverage. Yeah, even without the modern labels. Their success came from observation, experimentation, refinement, And the kind of proto-science really applied to solving very practical, if destructive, problems. It really makes you appreciate their ingenuity. And it's fascinating how those core principles demonstrated so powerfully in, you know, a trebuchet or a ballista are still absolutely fundamental to so much technology today. From theme park rides to space exploration, in a way. Makes you wonder, doesn't it? What other seemingly simple historical technologies might hold profound scientific insights, maybe ones we haven't fully appreciated or could even learn from, again, in new context? Something to think about. Thanks for listening today. Four recurring narratives underlie every episode. Boundary dissolution, adaptive complexity, embodied knowledge, and quantum-like uncertainty. These aren't just philosophical musings, but frameworks for understanding our modern world. We hope you continue exploring our other podcasts, responding to the content, and checking out our related articles at heliocspodcast.substack.com.