Mass Explained

Discussion in 'Physics & Math' started by Farsight, Dec 29, 2006.

  1. D H Some other guy Valued Senior Member

    Why? These are not theories. They are fanciful conjectures with pretty pictures that have nothing to do with the topic at hand. Most importantly, there is not a shred of mathematics behind them. Snake oil.
  2. Google AdSense Guest Advertisement

    to hide all adverts.
  3. Farsight

    Paulfr: I didn't say energy does not exist. Energy definitely exists. When it comes to what's real, yes we have unemployment. But you can't show me any of this stuff. It's a concept. And like money, it all disappears if you take the people away. So just how real is it? In physics we want to understand the universe. So we need to make sure we don't confuse what's real with what's not. For example wavelenght is real, but colour is not. I like this saying by Terry Pratchett: you could grind the Universe to powder and you won't find one single atom of justice.

    D H: You can kick yourself later when you actually read these essays and take the trouble to think about them instead of dismissing them out of hand. And you can keep on kicking yourself years later when you're teaching this stuff.
  4. Google AdSense Guest Advertisement

    to hide all adverts.
  5. (Q) Encephaloid Martini Valued Senior Member


    You mean real people? The ones who are unemployed? So, are you saying I can't show you real, unemployed people?

    So, wavelengths are real, but not their effects?

    Much like your assertions, quite appropriate.

    Like myself, I'm almost sure DH will risk a sore ass.
  6. Google AdSense Guest Advertisement

    to hide all adverts.
  7. Farsight

    Huh? The people are real. The unemployment concerns their condition. When we boil it down we're talking about their inaction. And when it comes to what's real, it's very simple to understand the difference between action and inaction. A photon is an action, the electromagnetic equivalent of a shout. You can conduct experiments with photons. But inaction isn't as real as action. It's like hypothesizing about being motionless -you won't find "motionlessitons" kicking around out there in the universe.

    Colour is perception. It only exists in your head. And your ass will be very sore once you cotton on that this is the real McCoy. But it'll be a while yet, because you can't even get past first base. To you square A is a different colour to square B, you don't understand why you're wrong, and you aren't interested in finding out.

    Please Register or Log in to view the hidden image!

  8. Fortuna Registered Senior Member


    I find your explanations rather confusing. But I have a bias, that is, I have a BS in Physics but I'm not a teacher. But niether am I really a physicist anymore, since I got my graduate degree in Organic chem and now I work in the private sector. ( Whenever I say that I always remember Ray from Ghostbusters, telling Egon and Vinkman who have just lost their jobs at the University, when Ray tells them, "You've never worked in the private sector, I have and they expect results !")

    I say that I am biased, because I find that at times I need to avoid reading any layman's explanations of physics. I believe that is because those of us who have the formal education have very fixed and formal definitions for concepts and topics in physics. We try to be very careful how we use certain terms and use very precise definitions of those terms.

    Teachers on the other hand like to find these simplified explanantions and analogies to teach students, and will relax some of the formal definitions. Sometimes one has to use intuition as a learning tool to initially understand these ideas. But, it is only an analogy to help one learn. The analogy usually has many shortcomings realtive to the concept being taught. Further, intuition is not at all useful in learning formal definitions.

    Bear this in mind as you read. It might account for what I'm saying here and why I find your explanation so thoroughly confused. It may be that you are only using a teaching analogy and I'm just pointing out its shortcomings (which is more or less a "Duh! - I know it doesn't really work like that, this is just oversimplified for teaching purposes")

    When you said ;

    But you can certainly feel its effects right in the palm of your hand in some cases! Hold a steel ball heated up to 60C vs one at 0C and pick them up in your hands. You certainly can feel the difference, and this is exactly energy, specifically thermodynamic energy. (quantifiable by the expression E = kT, but that's not important here). Thus, it is possible in several cases to distinguish different levels of energy in an object. This makes me question the general sense of your statement that, "You can’t hold energy in the palm of your hand".

    Ok, but it is possible to hold a thing in my hand and feel the effects of the [thermodynamic] energy it has. Agreed ?

    For a solid object or a specific size perhaps so. Of course this is not so for liquids or gases or very small masses. We cannot literally hold a gas in our hand and feel it. But, just like in the example above (of thermodynamic energy) What am I feeling ? Am I feeling "mass" or am I feeling the effect of that mass being in a specifically solid state ? Isn't it true that all I'm feeling is an electromagnetic force from the surface electrons which are electrically repulsing the surface electrons of my nuerons ?

    I have to conclude that, like thermodynamic energy above, I really cannot
    "feel" mass either. I can only feel the effects of a mass in a specific state in my locale.

    Now, I know that you are using the term "you can feel it" in the more general sense than a literal one. But, the analogy is still applicable. Think about it.

    In other words, mass is just as conceptual an idea as is energy. We define mass in a very specific way. (Classically, using Newton's laws and an objects resistance to changes in momentum (think of momentum as a vector quantity here) and this is not at all an intuitive definition). However, we have also defined that mass is directly proportional to weight. It is this "weight" that is striking your intuition as "more real" than energy. But once again, "weight" is an effect of mass.

    Does that makes sense to you ?
  9. Farsight

    Yes, that makes sense Fortuna. If you find it confusing I need to give it some attention.

    Perhaps the problem is to do with properties. People (usually younger people) talk about "pure energy" as if it's something tangible that you can get hold of, and they also talk about "a mass" as if mass is more than a property. But then when we mentally remove the properties of a thing one by one, in the end we find we have nothing left. I haven't gone into this in depth because I feel it's too complex, and would take me away from the essence of the essay, which was how momentum can be translated into inertia.

    But I do plan to revisit ENERGY EXPLAINED and talk more about properties. The essay needs some improvements, and the last paragraph is currently looking like this:

    Energy is the capacity to do work, and is in essence a volume of stress.

    You know you can’t hold stress in the palm of your hand, or tension, and a volume of it doesn’t make it something you can get hold of. That’s why you can’t hold pure energy in the palm of your hand. There is no such thing as “pure energy”, just as there is no such thing as “pure pressure”. But you can hold energy in your hand. It’s a subtle difference, but it’s very simple. Just squeeze a fist. Use your right hand. Squeeze it tight. Now touch your left thumb to your right thumb. Feel that blood pressure. Now look at the volume of your fist. Stress is pressure, and there’s a volume of it in that fist. Your hand has energy. And if you swing that fist, it has even more. As to how... well. I know mass and motion doesn’t sound like a volume of stress. So to explain it, I’ll have to explain mass...

    I'll also look at some changes here to hopefully clarify matters. Thanks for your feedback.

Share This Page