Genecks Posted August 31, 2012 Share Posted August 31, 2012 An object stays in uniform motion until acted upon by a non-zero net force... Ok... But there tends to be an object like air that will cause oxidation and a material to dissipate/rust over time, right? So, is that more in the realm of quantum physics or what? Link to comment Share on other sites More sharing options...
mathematic Posted August 31, 2012 Share Posted August 31, 2012 Are you asking about an object flying through air? In that case air friction will act a lot faster than rust. Link to comment Share on other sites More sharing options...
Genecks Posted August 31, 2012 Author Share Posted August 31, 2012 I'm talking about leaving a bar of iron on my table top. Isn't there a +/- netforce acting on it at all times, and that's why it's rusting? Link to comment Share on other sites More sharing options...
studiot Posted August 31, 2012 Share Posted August 31, 2012 (edited) Why do you think any of Newton's laws of mechanics have anything to do with rusting? Each our scientific laws are model of only some aspect of reality. It is important to apply the correct model to the part of reality of interest. Edited August 31, 2012 by studiot Link to comment Share on other sites More sharing options...
Genecks Posted August 31, 2012 Author Share Posted August 31, 2012 (edited) Why do you think any of Newton's laws of mechanics have anything to do with rusting? All our scientific laws are models of only some aspect of reality. It is important to apply the correct model to the part of reality of interest. I would think rusting would change the vector positions of the iron molecules. Edited August 31, 2012 by Genecks Link to comment Share on other sites More sharing options...
studiot Posted August 31, 2012 Share Posted August 31, 2012 Newton's laws are rarely used in chemistry and you need chemistry to understand rusting. However you are right that on a microscopic scale if a molecule moves it does so under the action of a force, subject to Newton's laws. It is really only sub atomic particles that move fast enough to require relativistic considerations. Link to comment Share on other sites More sharing options...
MigL Posted September 2, 2012 Share Posted September 2, 2012 All reduction/oxidation reactions involve swapping/sharing of electrons and so, are controlled by electromagnetic force, more specifically, because of scale, quantum electrodynamics. Link to comment Share on other sites More sharing options...
Evans Steven Posted September 8, 2012 Share Posted September 8, 2012 First of all Newton has three (3) laws of motion. One of them and the first one is the Newton's first law of motion (the law of inertia). It mentions that any object remains on its position unless and otherwise there is a contact with another external force. And also it says that any moving body remains moving on its own direction, by the same speed unless and other wise there is an external force influence. Newton's first law of motion is also called the law of inertia. The property of an object to resist not to change its state of rest or uniform motion in a straight line is called inertia. An object at rest tends to be at rest, an object in motion tends to continue its motion in a straight line, unless external force acted on it. THANK YOU!!! Link to comment Share on other sites More sharing options...
O'Nero Samuel Posted September 10, 2012 Share Posted September 10, 2012 Why do they always seperate chemistry from physics when it comes to questions like this? Link to comment Share on other sites More sharing options...
mississippichem Posted September 10, 2012 Share Posted September 10, 2012 Newton's laws are rarely used in chemistry and you need chemistry to understand rusting. However you are right that on a microscopic scale if a molecule moves it does so under the action of a force, subject to Newton's laws. It is really only sub atomic particles that move fast enough to require relativistic considerations. True, Newton's laws are rarely used explicitly by chemists. However it should be noted that from a theoretical standpoint, we need Newton's laws to build up all our statistical mechanics and ultimately kinetic molecular theory. So in an indirect way we use Newton's laws everytime we examine reaction kinetics. Everything you said is true and I agree. Just wanted to take a rare opportunity to promote the deep and interesting link between chemistry and mechanics. Many non-scientists don't realize the remarkable connection between fundanental principles like Newton's laws and complex emergent phenomena like chemistry. Link to comment Share on other sites More sharing options...
studiot Posted September 10, 2012 Share Posted September 10, 2012 (edited) Many non-scientists don't realize the remarkable connection between fundanental principles like Newton's laws and complex emergent phenomena like chemistry. That's because they are too busy enjoying the emergent fruits of these chemical phenomena like ice cream and candy floss and whisky. Edited September 10, 2012 by studiot Link to comment Share on other sites More sharing options...
swansont Posted September 10, 2012 Share Posted September 10, 2012 Why do they always seperate chemistry from physics when it comes to questions like this? One needs to be aware of the limits of applicability of any part of science, in part because of how we define things. Newton's laws were developed for mechanical systems. Even within physics, trying to reconcile mechanics with thermodynamics can be a problem, because of how work is defined (and whether you are off by a factor of 2 in the heat transfer as a result). Crossing the boundary between physics and chemistry can be problematic as well. So boundaries might arise simply to limit one to a self-consistent set of models and definitions. Link to comment Share on other sites More sharing options...
O'Nero Samuel Posted September 10, 2012 Share Posted September 10, 2012 Thermodynamics tells us that the enthalpy change of a system(allow me to call it heat content) is the sum total of the rms value of the kinetic energy of its molecules. Physics handles this quite conviniently, as long as the molecules are not reacting to form new products; in which case we stpp dealing with these mlloclles independently. Then we start talking about heat of reaction. Now here is a conclusion: we can solve the physics of small particles, even down to photons, as long as they are not reacting to form new particles. Please someone tell me I'm wrong. But when they are, in most cases, we just wait for the chaos to form systems, and know their composite element: this then is CHEMISTRY, eh? Link to comment Share on other sites More sharing options...
pantheory Posted September 11, 2012 Share Posted September 11, 2012 (edited) An object stays in uniform motion until acted upon by a non-zero net force... Ok... But there tends to be an object like air that will cause oxidation and a material to dissipate/rust over time, right? So, is that more in the realm of quantum physics or what? You might say that oxidation is in line with Newton's law. When it is acting upon something by the chemical process of oxidation potentially adding weight and porosity like an atmosphere. It also can slow down an object by friction if it is in motion relative to such an atmosphere. Water is also a good catalyst for oxidation so water/ gas/ water particulates also cause more friction. Realize that both friction and oxidation are external influences, resisting forces, or reactants that can influence/ slow uniform motion by acting upon a moving body. Newton's law remains unaffected by such processes. // Edited September 11, 2012 by pantheory Link to comment Share on other sites More sharing options...
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