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Air travels through different objects, but I am very confused because you see these pictures of cars doing wind tunnel tests and that smoke goes over the car to represent the cars aerodynamics. When you are driving in a real situation does some of the air travel through the windshield and if it does then why doesn't all air travel through the windshield.

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  • $\begingroup$ you have a gross misunderstanding. air does not go through solids at normal temperatures and pressures. The glass would break if the pressure were too great, but it will not become permeable in the way you visualize. $\endgroup$
    – anna v
    Sep 11 '15 at 6:03
  • $\begingroup$ @anna v thanks I am just a little confused about it but I have a better understanding about it now $\endgroup$
    – Ethan
    Sep 11 '15 at 6:05
  • $\begingroup$ So the pressure is greater resulting in air traveling over the object instead of in the object. So with an airplane no air goes through the plane except for the vents that allow air to travel through and make the ac $\endgroup$
    – Ethan
    Sep 11 '15 at 6:23
  • $\begingroup$ yes, designed vents $\endgroup$
    – anna v
    Sep 11 '15 at 6:27
  • $\begingroup$ Air only moves over an airplane instead of in the airplane is what I am understanding. $\endgroup$
    – Ethan
    Sep 11 '15 at 6:29
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Air does not travel through solid objects, Physically speaking. Air molecules are too big to get through gaps between atom in solid materials. However, that doesn't mean there is no exchanging of air inside and outside of cars. The most obvious example is air conditioning which sucks air from the outside and circulating it in the car.

Typically, when you driving with windows closed, there is an air pressure different between outside and inside of your car. Sometime, this different can be large if you are driving through fast moving wind. The windscreen, as well as any other point of your car, is built to withstand in this situation. Pressure different doesn't necessary mean air is leaking into your car unless the windscreen gave way.

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  • $\begingroup$ So air from the ac still makes its way out of the car though. $\endgroup$
    – Ethan
    Sep 11 '15 at 6:55
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    $\begingroup$ Yes, but your question is trivial. Please forgive me for saying that. I don't know what you have in mind when you asked this question, this is not a Physics question as far as I understand. $\endgroup$
    – TBBT
    Sep 11 '15 at 8:13
  • $\begingroup$ 's I realize that. I really couldn't find the right website. I'm in high school as a freshman and am not going to be taking physics for a year or two, so I dont really know what questions are about physics and what aren't. Also it just came up randonly when I was thinking about aerodynamics. My dad told me once that air travels through windows like a house window. So thats where the idea is from. I do forgive you. $\endgroup$
    – Ethan
    Sep 11 '15 at 8:21
  • $\begingroup$ @Ethan: When you learn some physics, this is an excellent site with friendly, helpful, very knowledgeable people who will be glad to answer your questions, even if you are new to the subject. You could in fact get an answer from a world leader. For this question, you should just be aware that, for the most part, gasses and liquids do not flow through solids. $\endgroup$ Sep 11 '15 at 19:55
  • $\begingroup$ @Ethan To me, this is certainly a physics question. Your father might have meant that air leaks around the edges of the window. Or that heat leaks through (which is to say, the window conducts heat better than the wall), which can cause the indoors air to cool down and move, giving the impression that wind is passing through. $\endgroup$ Sep 13 '15 at 1:37

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