Moreno Posted December 19, 2015 Share Posted December 19, 2015 What is the origins of thermal motion? Link to comment Share on other sites More sharing options...
studiot Posted December 19, 2015 Share Posted December 19, 2015 (edited) The short answer is greater thermal motion in some other body. In other words heat flows from hot to cold. Did you look at my last post in your other thread? Edited December 19, 2015 by studiot Link to comment Share on other sites More sharing options...
swansont Posted December 20, 2015 Share Posted December 20, 2015 What is the origins of thermal motion? Nothing is at absolute zero, and temperature is a measure of the motion of atoms and molecules. So there is thermal motion because we have energy. Maybe you could be more specific? Link to comment Share on other sites More sharing options...
Moreno Posted December 20, 2015 Author Share Posted December 20, 2015 Nothing is at absolute zero, and temperature is a measure of the motion of atoms and molecules. So there is thermal motion because we have energy. Maybe you could be more specific? But why atoms and molecules move chaotically? For example gas atoms have kinetic energy and move constantly, atoms and molecules in solid bodies vibrate. What is the origins of this motion and vibration? Link to comment Share on other sites More sharing options...
studiot Posted December 20, 2015 Share Posted December 20, 2015 (edited) Simply repeating the question doesn't show that you take any notice of what you are told. Molecules translate translate (move) randomly not chaotically the without a controlling influence. Chaotic vibration is inherent in Euler's laws of motion, otherwise the vibrations are precisely defined. Edited December 20, 2015 by studiot Link to comment Share on other sites More sharing options...
swansont Posted December 20, 2015 Share Posted December 20, 2015 But why atoms and molecules move chaotically? For example gas atoms have kinetic energy and move constantly, atoms and molecules in solid bodies vibrate. What is the origins of this motion and vibration? The motion and vibration occur because they have kinetic energy. That answer is not going to change, even if you ask the question again. If that doesn't satisfy your curiosity, then you need to come up with a new question. Link to comment Share on other sites More sharing options...
Moreno Posted December 21, 2015 Author Share Posted December 21, 2015 The motion and vibration occur because they have kinetic energy. That answer is not going to change, even if you ask the question again. If that doesn't satisfy your curiosity, then you need to come up with a new question. But how they initially gain kinetic energy? You could say, of course, that atom A gains energy from atom B and atom B from atom C, but since amount of planet Earth atoms is limited and Earth is surrounded by deep space there should be some mechanism how they all initially gain energy. Link to comment Share on other sites More sharing options...
Sensei Posted December 21, 2015 Share Posted December 21, 2015 But how they initially gain kinetic energy? You could say, of course, that atom A gains energy from atom B and atom B from atom C, but since amount of planet Earth atoms is limited and Earth is surrounded by deep space there should be some mechanism how they all initially gain energy. Earth's core and mantle have plentiful of unstable radioactive isotopes that are decaying and releasing energy. Uranium-235, Uranium-238 are just examples. They produce short-living unstable isotopes that decay quickly to other also unstable isotopes, and so on, so on. Until reaching stable isotopes. Also Sun is sending to us 1367 Joules of energy per second per each meter square area pointing at the Sun. It's energy that we're using directly (photovoltaic cells) or indirectly (f.e. food). Link to comment Share on other sites More sharing options...
Strange Posted December 21, 2015 Share Posted December 21, 2015 But how they initially gain kinetic energy? You could say, of course, that atom A gains energy from atom B and atom B from atom C, but since amount of planet Earth atoms is limited and Earth is surrounded by deep space there should be some mechanism how they all initially gain energy. The universe has always had energy. Link to comment Share on other sites More sharing options...
Moreno Posted December 21, 2015 Author Share Posted December 21, 2015 Earth's core and mantle have plentiful of unstable radioactive isotopes that are decaying and releasing energy. Uranium-235, Uranium-238 are just examples. They produce short-living unstable isotopes that decay quickly to other also unstable isotopes, and so on, so on. Until reaching stable isotopes. Also Sun is sending to us 1367 Joules of energy per second per each meter square area pointing at the Sun. It's energy that we're using directly (photovoltaic cells) or indirectly (f.e. food). So, how atoms or molecules gain kinetic energy by absorbing photons? Link to comment Share on other sites More sharing options...
studiot Posted December 21, 2015 Share Posted December 21, 2015 Asking where did the energyof the atoms and molecules come from in the first place is like asking where did the atoms and molecules themselves come from. We don't know, but if we did you would only be asking where did whatever spawned them come from and so on for ever. Link to comment Share on other sites More sharing options...
swansont Posted December 22, 2015 Share Posted December 22, 2015 Asking where did the energyof the atoms and molecules come from in the first place is like asking where did the atoms and molecules themselves come from. We don't know, but if we did you would only be asking where did whatever spawned them come from and so on for ever. I think we have a much better idea of where the atoms and molecules came from. But how they initially gain kinetic energy? You could say, of course, that atom A gains energy from atom B and atom B from atom C, but since amount of planet Earth atoms is limited and Earth is surrounded by deep space there should be some mechanism how they all initially gain energy. You're just moving the goalposts. Ultimately the answer is going to be "we don't know". We observe that the things in the universe have energy. Because of that, there is motion. Link to comment Share on other sites More sharing options...
pavelcherepan Posted December 23, 2015 Share Posted December 23, 2015 I think we have a much better idea of where the atoms and molecules came from. Up to a point. After that we get into very early stages of the Universe and our current theories break down, so I'd agree with studiot, that essentially we still don't know where atoms and molecules came from. Link to comment Share on other sites More sharing options...
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