Social Studies Connection

My physics PBL project is the Ballistic Car. This project demonstrates projectile motion. One example of projectile motion found in history is the cannon. I will be researching how the cannon affected physics.

The Cannon and Modern Dynamics

With the invention of the cannon, the foundations for modern dynamics were laid. Before that, the leading ideas on dynamics were from Aristotle. He said that thrown objects were "pushed" by the air that it was penetrating, which eventually got "tired" and stopped pushing, thus ending the object's flight. Later in history, John Philiponos rejected Aristotle's theory and introduced his own. He believed that the thing that kept the object going was not external, but internal. He called this impetus. "When you threw a stone it had something in it called impetus, and the impetus carried the stone along and as long as it preserved its impetus the stone would go on, when it lost its impetus it would fall" (Bernal 1997). This theory too would later be rejected upon close examination and experimentation with the cannon.

When the cannon was first introduced to Medieval Europe, Philiponos's theory became quite popular. As seen in the images below, people believed that a shot cannon ball would travel in a straight line until it started to lose its impetus, at which point, it quickly fell. The theory lost its validity when people noticed that the cannonballs did not travel in that manner and that the distance of the flight could be changed with the alteration of the shooting angle.

We now know from modern physics and engineering that when you change the angle at which you throw a projectile, the distance is modified accordingly. The first man to record this in a book was Niccolo Tartaglia, a pioneer in the studies of ballistics. He wrote in his book, Nova Scientia, "I was present at a dispute between gunners on the subject of what angle you must put the gun in order to get the greatest range, and they took bets on it. I gave this very careful mathematical consideration and worked out that the maximum angle must be 45 [degrees]" (Tartaglia). This meant that an object thrown at 45 degrees would obtain its maximum distance, and that any other angle that is greater than or less than 45 would result in a smaller distance. Using cannons, they could prove this to be true.