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I want to learn Physics But I'm 13

  1. Aug 20, 2007 #1
    Hi! I'm new here, and I wanted to ask everyone here, what should I do to learn Physics? The main reason that I'm asking, is because im only 13, so I don't know Trig or Calculus or anything else like that. Last year (7th grade) I was in Algebra, so thats how much math I know. And I believe you need to know Trig to be able to learn Physics, but I wanna learn Physics anyway, so can anyone here point me to some good UNDERSTANDABLE tutorials?

    Thank you!!!
  2. jcsd
  3. Aug 20, 2007 #2


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  4. Aug 20, 2007 #3
    This is a good general information website about physics. Topics include: Motion, Heat, Electricity, Light, and Modern Physics. Not much math but there are some graphs you need to interpret.

  5. Aug 20, 2007 #4


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    Welcome to the PF, Buck. You ask a good question. Just stay on the best, most advanced math track that your local schools offer, and take any physics classes that are offered, including AP physics and AP math as you get into high school. Also, if your school (or any other local schools) have a Physics club, join in and help to organize some projects and fun events. Keep it up son, and you will do well.
  6. Aug 20, 2007 #5
    the amount of trig/calculus you need to learn intro physics can be taught/learned in a day. msg me and i'll be happy to do that for you
    Last edited: Aug 20, 2007
  7. Aug 20, 2007 #6
    Dude he is only 13.
  8. Aug 20, 2007 #7
    :confused: i don't understand? what are you implying?
  9. Aug 20, 2007 #8
    Hes only completed algebra. So it'll probably take him 1 year to learn geometry, another year to learn Algebra 2/Trig, another year for precalculus and another year for calculus. That can't all be completed in ONE DAY!
  10. Aug 20, 2007 #9


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    As far as trig goes, you can do much of a college-level intro physics course with just the basic definitions of sine, cosine and tangent. They're mainly used with working with vector components.

    Algebra is definitely important. You need to be able to solve equations, find the slope of a straight line either from a graph or from its equation, use the quadratic formula to solve a quadratic equation, etc.

    One big gripe we have here about our students' algebra is that many of them have difficulty solving equations that don't have any numbers in them. For example, if we give them something like

    [tex]L = L_0 \sqrt{1 - v^2 / c^2}[/tex]

    (the familiar length contraction formula in relativity) and ask them to solve for v, they say "huh? there aren't any numbers!" We have to explain to them that we mean, "rearrange the equation so v is all by itself on the left side." And many of them have trouble with it, because they've apparently never done it in high school! All they've done is solve equations that have only one unknown quantity, along with numerical constants, to get a numerical value for the unknown. :frown:
  11. Aug 21, 2007 #10
    i think he's a little too young, but i could be wrong.

    The amount of calculus/trigonometry involved in most of newtonian mechanics is not too rigorous in itself, but the amount of mathematical maturity and intellect involved is something that needs to be built upon, and it cannot be built up all in one day.

    Or, you might be lucky and you could be a natural at it.
  12. Aug 21, 2007 #11
    There's so little from all those classes he needs. see jtbell's post. my intent was to show him sine cos tan and a couple other things and tell him to refer to me whenever he got to something he couldn't understand
    Bologna, i had it for dinner... but seriously every problem in intro mechanics can be solved with physical intuition and pretty much the same for intro e&m.
  13. Aug 21, 2007 #12


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    In my opinion, this is the sort of mentality that makes for a bad physicist. Basic maths skills should not be skipped over in an effort to leap ahead with learning physics. In my experience it is these basic maths skills that many physics students lack. I'm not saying that the OP should not be advised to study physics, just that if he wants to study physics using calculus, he better study calculus properly first.
  14. Aug 21, 2007 #13
    i never said he should skip any math classes. i said that if he wants to learn physics now i can help him. he will obviously take all of these classes and relearn all of these topics again with proper rigor. our entire education system is based on filling in gaps as we progress so learning something now in an elementary fashion will not hurt him later.

    edit im the last person to sacrifice rigor for results; the math methods book i'm reading right now stresses pure math.
    Last edited: Aug 21, 2007
  15. Aug 21, 2007 #14
  16. Aug 21, 2007 #15
    Last edited: Aug 21, 2007
  17. Aug 21, 2007 #16
    Could you teach me? I'm 14.
  18. Aug 21, 2007 #17
    Dudes, he's done algebra so you point him at Baez?!

    Sensible suggestions so far:

    1. Stick with learning maths (all the maths you can get taught) and physics at school.
    2. Read general "layman" physics books. My old favourites were books by Brian Greene, Feynman, James Gleick. I'm sure our forum can name some more books which are heavy physical intuition and light on maths.
    3. More maths. This can't be over stated. Physics is all about using maths to solve problems -- though later you'll probably find out about the nuances there within. This especially means practise your algebra. I'm at a pretty decent university, as far as its physics department is concerned, with its students considered some of the best in the world, and the undergrads who struggle with the course are those who can't perform algebra consistently well. If your maths isn't up to par, the physics will be hard.
    4. Experimental physics isn't to be neglected -- learn rigour with experiments. Personally, I've always been bad at this (thus why I'm a theorist), but maybe someone else can recommend some resources?
  19. Aug 21, 2007 #18
    Just take my example. I started learning physics when I was 12 and now I am 13 and I am in 9th grade. You would be surprised to know that I am researching on the most advanced topic of physics that is theory of everything and if you want to learn more about it you can search on it or you can also join http://www.toequest.com/ and I will help you there to understand all the topics - just give me a private message when you join and also tell me your user name. I discuss with scientists everyday and also read the latest research papers at http://arxiv.org/ Isn't that fantastic. Actually, I can help you a lot. Just note my e-mail address - lakshya_micheal@yahoo.co.in and also give your address. My young friend, you are like me and I assure you that without learning whole mathematics and physics of High School you can advance much. Just pm me or mail me if you want learning resources or how do you start because I want to talk to you privately about all these things. My friend, we can change the whole world and I know you have the potential to make the theory of everything which I will call TOE from our next discussion. I say you must cram the word TOE. If you want an education link then take this for this time:
    This is a physics link. If you want to see maths link just click hyper math link below the main frame ah......... you will find it easily.
  20. Aug 21, 2007 #19


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    But how do you intend to teach someone calculus in a day so that he can then go on to study physics using calculus? I suggest that the OP use the mathematical tools he knows already to study physics-- a lot of physics needs only basic algebra anyway-- and not try to rush learning calculus, as this will probably cause confusion at some time the future.
  21. Aug 21, 2007 #20
    Hi Buck, I'm pleased to hear about your interest in physics. I started reading books on physics when I was somewhat younger than you (though I didn't know that they fell under the umbrella subject of "physics"). This was before the Internet became popular amongst young people, so I would often just go to the science section of the library and get whatever books caught my interest. Though I think this can be supplemented with information from the web today, I think it's still a good approach. At the library you can find many books on various topics in physics written to a layperson audience, meaning that you can actually understand them. One popular book I think you might like is Stephen Hawking's "A Brief History of Time."

    As far as the whole math issue goes, I don't think this is the time for you to worry about the mathematical aspect of physics. To be sure, you should pay greater attention in your school's math classes, now that you know you're interested in physics (and it'll pay off even if you decide to do something else). But I wouldn't go out and try to learn multivariable calculus right now, or anything.
  22. Aug 21, 2007 #21
    yes pm me
    did you read the baez page? although it starts starts with suggestions for books from calculus up it starts physics books suggestions from intro up. i want to emphasize how bad i think "layman's" physics books are. they will teach him absolutely nothing and if he's like me they will frustrate him because they just state things without explanation. knowing about physics is one thing, knowing physics is another.
    honestly how much calculus did you use in your intro physics classes? in my intro mechanics class we were told the work integral, it was not derived and we weren't given functions to integrate. i had to do one, one!, real integral in intro e&m for the force on a point charge from an infinitely long wire. the rest was hand waved away just like solutions to maxwell's equations are hand waved into existence. again i didn't intend to teach anyone calculus, i said i could teach him how much he needed to know for intro courses.

    and even then honestly if i did want to teach him calculus in one day i would present the two pedagogical problems, slope at a point and area under a curve, and be done with it. a little fundamental theorem of calculus, a little mean value, rolle's and everything else is details.
  23. Aug 21, 2007 #22
    It is extremely unlikely that a 13-year old who has only learned some algebra will be able to teach him/herself mechanics from Goldstein and electromagnetism from Jackson. He/she would be better served reading layman-oriented physics books like Hawking's A Brief History of Time, Gamow's Mr. Tompkins series, Greene's The Elegant Universe or even Penrose's Road to Reality while trying to learn as much math as possible. I agree that the basics of the math required for freshman-level calculus-based physics could be taught in a highly-condensed form in a short period of time (on the order of one week), but at that rate one would not learn enough of the techniques to be able to solve any meaningful problems. I think single-variable calculus could be sufficient background to learn mechanics at the level of Kleppner and multivariable calculus would be sufficient to learn electromagnetism at the level of Griffiths, but I would be hesitant to recommend a more aggressive program (e.g. Goldstein and Jackson).
  24. Aug 21, 2007 #23
    Ice109: I'm sure if you two put some effort into it, you can get a long way into grasping enough maths to allow some pretty decent progress into physics. However, that's assuming that the student is already proficient in algebraic manipulations. It's a bit hypocritical of me to cite the proverb about running before you can walk -- but it's a proverb for a reason.

    To the OP: you're only 13 -- much younger than most of us old people here -- there's no hurry for you! Learning things broadly as thoroughly will give you new insights into problems that other people won't.
  25. Aug 21, 2007 #24
    i've stated and restated several times, the idea is not to attack undergrad physics classes, the idea is to attack INTRO CLASSES which require very very little math. i've also highlighted the fact that baez's page begin's with INTRODUCTORY PHYSICS BOOKS suggestions.

    do people not read the entire thread before commenting?
  26. Aug 21, 2007 #25
    The point I'm trying to make (admittedly very indirectly) is that there is little point in trying to learn physics without calculus. Of the three general physics texts listed on the Baez page, the only one I am directly familiar with is the Feynman lectures, which I am taking to be representative of the other two as well. The Feynman lectures are admittedly great for developing conceptual understanding, but they still require at least some calculus background, and they are devoid of problems, which is where the physics learning actually takes place. Assuming the other two books are at roughly the same level, I still maintain that one would be best served reading layman-oriented physics books to develop/maintain interest in the subject while trying to develop sufficient mathematical background to learn physics properly.
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