Strange Posted January 17, 2018 Posted January 17, 2018 1 hour ago, trevorjohnson32 said: Sorry guys not buying it I'm reading ; "Yes electricity can "travel" through vacuum. But no one calls it arcing because there is no glow (no particles that can get excited -> no photons -> no glow, just invisible electrons). Vacuum tubes for example make use of electricity that is traveling through vacuum." OK. So studiot already gave the example of electrons passing through space and carrying current. This is what happens in vacuum tubes and cathode ray tubes (old-timey TVs). And this is where I guess it comes down to a definition of terms. I wouldn't describe this as "space" conducting electricity because you have to put the electrons into the empty space; it is the electrons that carry the current. But as the electrons are flying through space (instead of, say, a piece of metal) then you could say that the current is flowing through space. The difference is that a metal has lots of electrons already available to carry the current. Space doesn't until we add them (or ionise the gas atoms to create an arc). Does that make any more sense? (p.s. where did the quoted text come from? It is always helpful to provide sources!)
studiot Posted January 17, 2018 Posted January 17, 2018 Actually there are some more basic questions to answer like What does Trevor mean by 'electricty' ? Does he mean AC or DC for instance and does he understand that the answrr could be (and is) different depending. And what characterises 'conductor' or an 'insulator' ? I assume Treveor has some application in mind, which is what I asked about twice now.
mistermack Posted January 17, 2018 Posted January 17, 2018 I wouldn't think of space as a conductor. Not in the sense that copper wire is a conductor. In copper wire, the electrons don't have to physically travel from one end to the other for energy to be transmitted. The current can be transmitted by one particle pushing it's neighbour, which pushes it's neighbour, and so on, in a chain, so that energy is transmitted to the other end. In other words the copper is taking an active part in conducting the current. Whereas empty space just permits an electron to jump. It's a bit like air. I would say that air conducts sound, but I wouldn't say that air conducts a bullet. It just allows the bullet to pass, whereas it takes part in the passage of sound. 2
Strange Posted January 17, 2018 Posted January 17, 2018 6 minutes ago, mistermack said: I would say that air conducts sound, but I wouldn't say that air conducts a bullet. That's good. I was trying to think of an analogy for the difference between the electrons in a metal and firing electrons through a vacuum.
studiot Posted January 17, 2018 Posted January 17, 2018 1 hour ago, mistermack said: I wouldn't think of space as a conductor. Not in the sense that copper wire is a conductor. In copper wire, the electrons don't have to physically travel from one end to the other for energy to be transmitted. The current can be transmitted by one particle pushing it's neighbour, which pushes it's neighbour, and so on, in a chain, so that energy is transmitted to the other end. In other words the copper is taking an active part in conducting the current. Whereas empty space just permits an electron to jump. It's a bit like air. I would say that air conducts sound, but I wouldn't say that air conducts a bullet. It just allows the bullet to pass, whereas it takes part in the passage of sound. Yes I like it too, especially as it encapsulates what I said in my first answer. Another thing about a conductor is that it comes from the word 'to lead'. A conductor provides a path of least resistance and contains or confines the current so that it passes (is lead through) the conductive path rather than an alternative more insulating one.
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