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Q's regarding Conceptual Physics

  1. Feb 8, 2010 #1
    I read some books trying to understand the concepts of physics and here are the parts I got stuck at, if you could help me out, I would move on :)

    1. Why cant momentum and position not be determined at the same time?(Heisenberg Uncertainity Principle)
    2. How is 1 electron shot at a time and how does a device detect it?(Double Slit Experiment)
    3. Isn't the center of the universe the point where big bang happened?(Special Relativity)
    4. Both in Fusion and Fission, which energy is being released/converted?(Chemistry)
    5. What would happen if form an object thats moving at a speed of life, light is thrown? Would it travel forward? Why is speed of light unrelevant to other speed?(Relativity)
     
  2. jcsd
  3. Feb 9, 2010 #2
    1. Why can't you precisely say the wavelength of a short pulse or the position of a continuous wave?
    2a. Just decrease the intensity until it is statistically unusual for pairs to coincide.
    2a. By triggering some kind of http://en.wikipedia.org/wiki/Photomultiplier#Structure_and_operating_principles".
    3. GR, nor SR, think of ants living on a 2-dimensional universe, that is drawn onto a balloon, which is being inflated. The big bang did not happen at any single place in the universe, the entire universe is expanding fairly evenly everywhere.
    4. Depends. Generally, energy is released whenever the nucleus gets more similar to the nucleus for iron, which in some sense is "just right" for the nucleons.
    5. The fact is that velocities don't add in the way Newton thought they did...

    Start working through an introductory undergraduate textbook. The concept books may help you identify what sounds interesting to you, but you need to do the maths and exercises in order for you to ever truly understand the theory yourself. (It tends to become insulting when we see people who go on trying to figure it all out "solo" in their own heads whilst deliberately ignoring the distilled successes developed from many generations of more concentrated expertise.)
     
    Last edited by a moderator: Apr 24, 2017
  4. Feb 9, 2010 #3
    I read in a book that I think was a quote from Einstein but could have been some one else very great that said theory should be understood without math, and with math to be a physicist. I am not ignoring it, I will move on to that part, but first, I want to understand it through this so called fairy tale method. Please do not be insulted, it surely isn't meant such.

    1. Still didn't answer the question.
    2. Some popular physicist due to this have went a little hardcore with their interpretation to include consciousness which is still unacceptable by the majority. What are your thoughts on this, is it just a difference in matter of opinion? Since if something is unexplained, I dont see what seperates one opinion than another except saying, we dont know, I dont see any difference between one physicist to another.
    3. True the whole universe is expanding, but isn't there a point its expanding form and according to a theory, won't it get back to that point then big bang again?
    4. From where is that energy released? What form was it in earlier?
    5. I understand there if proof, but is it not possible for the concept to "make sense" in my head? I just dont get it how speed of light is unrelevant to other speed.
     
  5. Feb 9, 2010 #4
    1. He did, but here is some exposition: "Just as it is nonsensical to discuss the precise location of a wave on a string, particles do not have perfectly precise positions; likewise, just as it is nonsensical to discuss the wavelength of a "pulse" wave traveling down a string, particles do not have perfectly precise momenta (which corresponds to the inverse of wavelength). Moreover, when position is relatively well defined, the wave is pulse-like and has a very ill-defined wavelength (and thus momentum). And conversely, when momentum (and thus wavelength) is relatively well defined, the wave looks long and sinusoidal, and therefore it has a very ill-defined position." - WIKI

    2. Interpretations are like assholes... do I have to finish the rest?

    3. It's a metric expansion, so it's expanding from EVERY point. Also, it seems that we are destined for heat-death rather than a big-crunch.

    4. Not completely sure about this one... Everything want's to be iron... and fusing light stuff closer to iron releases energy and fissioning heavy stuff closer to iron releases energy. The energy is often released in different ways... like free neutrons and gamma rays.

    5. It's just how physics works! You can get it to make sense in your head by learning how it works under different circumstances. Lorentz transforms for example.

    Also, we DON'T have fundamental reasons for everything, and you have to know it by understanding the math. The Paulie exclusion principal for example states that if you exchange two fermion particle wave-functions you have to reverse their sign. Why? We don't know, it's just a step in the mathematics that allows it to spit out reasonable (normalizable) answers. And why do particles act like waves and particles at the same time? We don't know. Why don't electrons just fly right into the proton? We don't know. We can say, well, if we apply the HEP then the electron gains more and more momentum as it gets more and more confined but why should any of this be at all? There is not a fundamental answer that we know.
     
  6. Feb 9, 2010 #5
    My plan is to major in Math and study physics as a hobby, do you think through this I can gain understanding of both?(I am also interested in psychology and biology but dont think classes are necessary...I should be able to grasp it as i have good genes in that department)
     
  7. Feb 9, 2010 #6
    Doesn't that sound sort of arrogant to you? (If your genes are so distinctive, why do you need to ask basic questions addressed by introductory textbooks anyway?)

    I'm not objecting to more people learning these subjects as a hobby rather than full-time, just saying proper textbooks are still the more effective way of achieving non-illusionary results.
     
    Last edited: Feb 9, 2010
  8. Feb 9, 2010 #7
    Well Cesium, let me tell you, I am sick of trying to learn something in the form of religion. If you ask all martial artist, which is best, its like asking people which political party or which religion is. People become attached and what I say ends up sounding rude or arrogant. A person doesn't have time to get black belt in every martial art in existence, still, he can become a better fighter throughout some disciplinary training, and his own choices.(understanding the science behind fighting instead of abiding by the cultural rituals) Therefore, if I want to learn everything in the world, it doesn't mean I have to go through classes and complete assignments. There are alternate paths to knowledge. I dont think I am smart enough to grasp math without someone's help, but so far, in psychology, I have found myself a step ahead, and in biology, its more of a matter of reading news than needing help in teaching, unless you want to become a doctor and operate. I also want to become an electrical engineer but I plan on experimenting by myself with tearing electronics apart like a son learns in the company of a father. I think focus makes us closed minded and therefore 2 people from different religion often cannot reach a mutual conclusion. Unlike physics, which works on math, something I need to learn first to understand, everything else is simply a matter of aknowledging scientific method.

    Would you agree with this thought of mine?
     
  9. Feb 10, 2010 #8
    4) In fusion, the energy is released beause when the two isotopes are initially put together they then release another particle (what type of particle this is varies on the isotopes), which puts them in a high energy state seeing as the energy which was used to bind that particle to the nucleus is no longer needed but still present, they then get rid of the excess energy and go into a lower energy state which is what blows up your cities and makes the sun shine.

    In fission the principle of energy release is similar, as in the reaction releases 3 neutrons from the original isotope in addition to the two waste products. Again, the energy which was used to hold the neutrons in place is no longer needed and released.
     
  10. Feb 10, 2010 #9
    Modern electronics are not that simple. Modern ANYTHING is not so simple...


    Majoring in math is good tho. Also, I think you will find you are more ignorant in these subjects than you think, you just don't know what you don't know. If you don't want to take classes to learn something then you better have a solid way of learning it yourself like good books and lots of practice...

    No-one said you have to 'focus', but obviously if you want to be good at two things it will take longer than one thing.
     
  11. Feb 10, 2010 #10
    Am I correct to assume that learning everything is like reading news?(unless you want to memorize) Except physics because it requires understanding of math which is deeper than just a langauge. Therefore, for everything else, I would need discussion boards, books, but would I need self-transformation like in mathematics, you need create 1 step before you can ascend?
     
  12. Feb 11, 2010 #11

    russ_watters

    User Avatar

    Staff: Mentor

    No.

    And a few things about electrical engineering:
    1. There are many career fields that require a degree. You may see it as just a piece of paper, but your employer will see it as proof of a certain level of knowledge.
    2. Most of electrical engineering cannot even be seen with your eyes, much less learned by tearing apart electronic devices.
    3. Thousands of people have made major contributions to the field. It is unreasonable and even arrogant to believe you can re-create everything they have accomplished by yourself, from scratch.

    Your hostility toward structured/formal learning will not serve you well in life.
     
  13. Feb 11, 2010 #12
    So if I want to learn those things, there is no way around but getting a degree in it?(Difference between expert and informative.)
     
  14. Feb 11, 2010 #13
    You can learn things however you want. But your method of 'reading the news' is very flawed.

    This and a few other resources is sufficient to teach you just about anything they learn in the first 4 years of college for any degree. But you actually have to do it... for years... so you may as well go to school so they can hand you a degree for all your trouble too.
     
  15. Feb 11, 2010 #14
    Hmm....understood. Would you say this wont apply at Biology since they make you memorize so many names? My personal opinion as I am a bit religious on the eastern side, that the psychology they offer works for me plus I can learn a little modern by myself. I basically want to have complete theoretical knowledge and a little understanding of how things are made. So later, I can invent something, what course of action would you recommend for this? Major in Math, Electrical, and self study others?

    According to this page, http://www.engineergirl.org/?id=5486, I'll have to major in both, I dont think I have time for this, I guess what I am getting at, these end up being practical knowledge which I can learn later on my life as I need use for them....but theoretical is someething which requries time to grasp and building blocks to advance understanding.

    Is this a terrible plan?
     
  16. Feb 11, 2010 #15
    First off, I don't understand half the stuff your saying. Having said that.

    If you want to invent, I would recommend you get ONE degree in the thing that most interests you and learn other stuff on the side. Getting that one degree will teach you to learn, and flesh out all your other skills like writing which it seems could use some help and let you get a good job.

    Many universities also offer hybrid degrees that include aspects from multiple disciplines... Maybe look into that?

    Also, don't worry about Math, if you major in engineering you will learn plenty math.
     
  17. Feb 11, 2010 #16
    Thanks, how do I search for the ones who do offer that?

    Btw, I was just imagining if there is a possibility that maybe a shortcut exists, like seen in the movies where an unorthodox professor teaches his kids, I have always seem to learn better by myself at a slower pace, through details, I adapt better anyways. How did I come off as insulting, arrogant, and flawed without reason?

    In my high school, my teacher told me he couldn't understand till he started teaching, therefore, I dont look high on the teaching system since most of my friends dont get what is going on, but try to find alternates around it to pass. Not to mention with the heavy workload, a healthy lifestyle is impossible.

    How about PhD? I heard some colleges let you skip masters? Can I take PhD on Hybrid? Would I by then gain complete understanding? If I want to learn Math completely for instance, would PhD be necessary?
     
  18. Feb 12, 2010 #17
    You have to be kidding. Skip masters? Learn math completely? Like seen in the movies?

    You don't need a shortcut... you're going to need allot of remedial classes. College is not an extension of high school, everything is different. I'm sure the classes will be sufficiently challenging to keep your attention and regain your respect for the educational system.

    EDIT2: Also, you can take hybrid degrees any pretty much any good university. But I'm not sure if you can take them all the way to doctorates.
     
    Last edited: Feb 12, 2010
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