The Physics of War Read Free Page A

them.
    Walls, however, were merely a challenge to the Assyrians. They weren't going to let walls stop them, and they soon began designing and building siege engines to get through them. Actually, they were nothing more than huge battering rams constructed of wood. In many ways they resembled a gigantic tank on wheels. They usually had four wheels, but some of the later ones had six. And because they were so big and heavy, it usually took thousands of soldiers to move them.
    As terrifying as they were, the defenders usually fought back with all they had. The siege engines would have to be pushed up to the edge of the wall, and it soon became obvious that the pushers and anyone inside would need protection while it was being moved forward, since the defenders would bombard them with arrows and rocks, and as the siege engine moved close to the wall they would try to set it on fire. For protection, the Assyrians built small towers atop their siege engines for their archers. These archers would fire back at the defenders as the siege engine was being moved forward.
    When the siege tower, which was frequently several stories high, reached the wall, a huge battering ram with an iron (or bronze) “bit” was rammed again and again against the wall. It was powered by a large contingent of soldiers. Slowly it would chip away at the wall, and as this took place, fierce fighting would go on between the Assyrians and the defenders. Fire, of course, was a major weapon of the defenders, so the Assyrians had to cover their engine with a huge sheet of animal skins that was kept wet.
    As time passed, walls were built thicker and thicker, and eventually stone walls were used. But the Assyrians merely built bigger and bigger siege engines with more effective metal bits. As stone increasingly came to be used for the construction of city walls, it became more and more difficult for the siege engines to batter them down. Nonetheless, they continued to have some success. One of thelargest siege engine of ancient times was the Greek helepolis ; over one hundred feet high and so stable it could not be tipped over, it far outstripped the scale of Assyrian siege weapons.
    Over time, the Assyrian Empire began to weaken. It had collapsed by about 610 BCE.
    GREEKS AND THE BEGINNING OF PHYSICS
    While the Assyrian Empire began to fade, other nations began to flourish, including Babylonia, the Persian Empire, which lasted to 330 BCE, and Phoenicia, the seafaring state that lasted to about 539 BCE. But the ancient civilization that had the biggest influence on physics was Greece, which consisted of city-states that began coming into power about 800 BCE. Indeed, before the Greeks, there was little if anything that could be called physics, and there was little science in general. Furthermore, the first scientists were not referred to as such; they were referred to as philosophers. But there's no doubt that one of their major aims was to understand the world around them. They were particularly interested in motion and matter. Why did things fall? And what exactly was the role of air, water, fire, and the earth beneath their feet? What was time? And their curiosity extended to the sun, the moon, and the stars. How far away were they? How big were they? Why did they seem to move?
    The first science was, no doubt, a form of physics. It was not what we think of as physics today, but it did include many of the same topics. It was drawn from astronomy, mechanics, optics, and areas of mathematics such as geometry. The early Greek philosophers set out to understand the mysteries of the earth and the known universe, and although they arrived at some ideas that may seem strange to us today, they did make important advances. One of the biggest advances was to move away from mythological explanations for the phenomena they observed. Instead, they developed logic and learned to look for reasonable and logical explanations.
    One of the first of these philosophers was