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Understanding physics conceptually

  1. Jul 10, 2014 #1
    Hello all,

    My physics teacher told me that there are two ways to understand physics: conceptually and numerically (doing physics problems based on math). He told me that knowing how to do numerical problems doesn't mean you understand physics conceptually.

    Is this true? If so, how do I understand physics conceptually?

    sorry if this is posted on the wrong side of the forum
     
  2. jcsd
  3. Jul 10, 2014 #2
    Somewhat - physical intuition (being able to determine if something makes sense our what something should look like) takes time to build. Also, some problems will ask you things like calculate the speed of a ball after it has fallen from a building for 3 seconds. There are plug and chug formulas for these problems. Do it is possible to input without understanding.
     
  4. Jul 12, 2014 #3
    other ways

    Alright, thanks. It looks like I'm on the right track. Can someone tell me of other ways to build a conceptual understanding of physics besides doing problems?

    Thanks
     
  5. Jul 12, 2014 #4

    WannabeNewton

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    Drink some coffee and do more problems.
     
  6. Jul 12, 2014 #5
    I think it can be productive to think about concepts apart from doing problems. I learn subjects by coming up with a pseudo-history of how they might have been invented. It can also be fruitful to ask why such and such result is important or would it be true if I dropped this assumption or that assumption.

    As far as problems go, there's not just one way of doing problems. For example, Wheeler has a "moral principle" that you shouldn't calculate until you already know what's going to happen. You can also try to think about what the point was and what you should take away after you finish a problem.
     
  7. Jul 12, 2014 #6

    SteamKing

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    How about doing experiments? For a lot of physical experiments, you don't need a fancy lab or a lot of shiny equipment. After all, the only thing Newton had was his mind and an apple tree, so the story goes.

    As the great applied physicist Yogi Berra explained, "You can observe a lot by watching." and, to paraphrase him, "Physics is 90% mental; the other half is experiments." :biggrin:

    http://en.wikipedia.org/wiki/Yogi_Berra
     
  8. Jul 13, 2014 #7
    Interesting. Is there any website that has list of experiments one can do with an introductory physics background?
     
  9. Jul 13, 2014 #8
    Basically, you should do every problem in two different ways. First, you should use conceptual physics to form a reasonable "guess" about what the answer will be. Second, you should use numerical physics to calculate a more precise answer. If your numerical result is different from what you think it should be conceptually (e.g., your answer is negative, but you expect it to be positive), then you need to either go back and fix your calculation or you need to fix your conceptual model.

    By doing it two ways, you're a lot more likely to catch and fix errors, which will improve both your course grades and your actual physics ability. People who aren't good at conceptual physics tend to grind through a calculation and just trust the result. They complain about how they always lose marks for making silly little mistakes, but most of those silly mistakes would probably have been caught if they had taken a few seconds to check whether their answers made sense conceptually.
     
  10. Jul 13, 2014 #9
    question for lazer

    So, basically you mean this:

    Let's say that you're examining what the initial height of the ball was when it was falling due to gravity. What happens to it. Initially, it has potential energy. As it falls, that potential energy turns into kinetic until all the energy right before it hits the ground is kinetic.

    Now for the numerical part: PE(initial) + KE(initial) = PE(final) + KE(final). Skipping over some steps, you'd get: mgh=.5mv^2. Now, do algebra and solve for h.

    Is this what you mean by conceptual first, numerical second?
     
  11. Jul 13, 2014 #10
    question for lazer

    So, basically you (thegreenlazer) mean this:

    Let's say that you're examining what the initial height of the ball was when it was falling due to gravity. What happens to it. Initially, it has potential energy. As it falls, that potential energy turns into kinetic until all the energy right before it hits the ground is kinetic.

    Now for the numerical part: PE(initial) + KE(initial) = PE(final) + KE(final). Skipping over some steps, you'd get: mgh=.5mv^2. Now, do algebra and solve for h.

    Is this what you mean by conceptual first, numerical second?
     
  12. Jul 13, 2014 #11

    SteamKing

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    Google "simple physics experiments" and take your pick.
     
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