# Tag Info

23

I'll try with some calculations : please, check it and the formulae used ... A solid ball with a mass $m$ of $1$ kg falls (with the usual approxiamtions : no drag, etc.) with an acceleration $a$ that is about $10 \ m/sec^2$. This means that falling from a tower $80$ meters heigh, it will touch ground after $4$ sec, with a final velocity of about \$40 \ m/...

17

In short, you were taught that Aristotle was wrong because he was wrong. He didn't make a prediction, he made an observation about rock and feather, and then sloppily generalized it to all objects without a second thought. The subtle effects you are describing weren't even noticable in his time, but that a feather falls slower because it is much more ...

11

Air or more generally medium resistance was not yet treated as a separate effect in Aristotle's time. Nor was there a clear idea of motion in a vacuum, in fact most ancient Greek philosophers, including Aristotle, did not believe that vacuum exists. So he had to explain phenomena as they are observed, resistance and all, and without the benefit of ...

11

No. Aristotle was not necessarily wrong. This is in substance Carlo Rovelli's view in Aristotle’s Physics: a Physicist’s Look. As the abstracts announces it Aristotelian physics is a correct and non-intuitive approximation of Newtonian physics in the suitable domain (motion in fluids), in the same technical sense in which Newton theory is an ...

10

Yes, Aristotle was wrong about gravity. But I think it is unfair to say “that Aristotle was responsible for holding back physics for centuries”. The ones who held back physics for centuries were the late-antique and mediaeval (Christian, Muslim and Jewish) so-called philosophers who transformed Aristotelianism into an ossified dogmatic doctrine. Aristotle ...

7

That Aristotle (and you with your example) are wrong is proved by the following simple argument: imagine two bricks of equal mass. Each of them falls with certain acceleration. Now glue them together and let them fall. According to Aristotle two bricks will fall faster than each brick separately. It is evident that this is absurd: what difference does it ...

4

From "Queries and Answers," Isis 41, no. 2, linked to by sand1 in the comments above, we see that the proof of the sphericity of the earth based on the fact that the masts of a distant ship are visible above the horizon when the body of the ship is no longer visible ...has been attributed to Aristotle in De Caelo, but it does not appear there. It does, ...

4

I dug up some text from a translation of "on the heavens." There are similar disputes about the shape of the earth. Some think it is spherical, others that it is flat and drum-shaped. For evidence they bring the fact that, as the sun rises and sets, the part concealed by the earth shows a straight and not a curved edge, whereas if the earth were ...

4

Historians believe that the extant version of Problemata was not penned by Aristotle personally, but “while the Problemata is not the genuine Aristotelian work, it nevertheless contains an element derived from such a work”. Problemata XXXII.5 discusses breathing under water, including the oft quoted passage interpreted as referring to a diving bell:”Why do ...

3

For Aristotle : Problemata Book XXXII, 960b,30-31 : “divers to respire equally well by letting down a cauldron”. Parts of Animals, Book II, 659a,5 : “Some divers, when they go down into the sea, provide themselves with a breathing-machine, by means of which they can inhale the air from above the surface while they remain for a long time in the water.” For ...

2

Physicists now tend to think in terms of effective theories; that is a theory which is accurate in a certain energy regime but fails in another. Thus, for example we get super-gravity as a low energy effective (ie approximate) theory of string theory. It's not quite fair to compare Newton and Aristotle after all a span of two millenia separates them. This is ...

2

Actually Carlo Rovelli considers the situation ignoring any viscosity/friction effects and points out that a body still falls slower in a denser medium. Consider a mass of specific gravity 2 falling through water. The net gravitation force is mg/2 but the mass is still m, hence the acceleration is halved. Of course the specific gravity of air is 0.0013 so ...

2

Aristotle concluded in his law of motion that the speed of an object depends on the viscosity of the medium it is in. In keeping with this line of thinking, since a perfect vacuum has zero viscosity, the speed of a falling object should approach infinity, as viscosity approaches zero. Galileo in his incline plane experiment identified the role of gravity, ...

2

Galen's theory of conception, and its relationships to Hippocratic Aristotelian and other ancient theories, is discussed by Boylan in The Galenic and Hippocratic Challenges to Aristotle's Conception Theory Hippocrates and Galen were dual seed theorists, so for them both male and female produce seeds that contribute to inheritance in the offspring, but the ...

1

There were no Roman soldiers in Greek lands when Aristotle died. Probably he died of natural causes, though I've heard of a speculation that he was murdered on the order of Alexander the great. It is true that at some point Alexandre went crazy and started killing his friends, for example Callisthenes, a great nephew of Aristotle. But I think this ...

1

Actually, if we are talking about Earth, there is another sense in which Aristotle was (accidentally) right, Earth has an atmosphere, and an atmosphere exerts a drag force on falling objects. It is not difficult to calculate terminal velocity and if we assume drag is proportional to velocity (R = kv), at terminal velocity acceleration and hence resultant ...

1

Everyone makes mistakes. Look at Newton, even though he knew perfectly well that action at a distance was philosophically speaking, nonsense, he still went with it because he could see no way past this impasse. It was only after Einstein we see where the mistake is. Neverthless, we don't belittle Newton for not inventing general relativity, and celebrate ...

1

You are right that a bigger object will reach the ground in a miscroscopically smaller time if dropped independently. Note however that if dropped at the same time, this will still not be the case, as the earth will be attracted to the force of gravity created by both of those objects.

Only top voted, non community-wiki answers of a minimum length are eligible