So, in a physics lab I TA, we are doing a lab in which part of it, the students try to do Faraday's Ice Pail experiment. For part of it, they need to charge a piece of metal at the end of a insulating rod. To do this, the guy who designed the lab did the following. He has a voltage supply, and sets it to 2000V. Now, this is very important. He attaches the positive output of it to a large metal sphere (just like a Van de Graaf sphere, but not powered or anything. Just at the top of an insulating rod). And he doesn't attach the ground of the power supply to anything. He claims that some positive charge should move to the metal sphere. We then have another (insulated) metal sphere close to the first one, which is supposed to exhibit charge separation. Then, the students should be able to rub that piece of metal to various parts of this second sphere, and get different charges (positive if it's on the side of the second sphere farther from the first sphere, negative if it's on the closer side) on this piece of metal. Experimentally, this just wasn't working. The piece of metal just didn't seem to be getting charged (putting it inside metal containers with an electrometer attached). Now, this immediately set off alarm bells in my head. We've had it drilled into our heads since day 1 that in direct current circuits, no current flows unless there is a complete circuit. Of course, there is a way current can flow. If there is a capacitance between the first metal sphere and the ground of the PSU, it would act as a small capacitor and allow some positive charge to flow to the sphere, and a small bit of negative charge to flow out from the electrode of the PSU. The head guy's logic was thus. We know that when we attach the positive electrode to the metal sphere, the sphere must become the same potential (2000V here) as the PSU. He thinks that this means a "tiny" bit of charge flows from the PSU to the sphere, to put it at the same potential. This is what he thinks should allow us to do the experiment. I think that it puts it at the same potential, but no charge flows (because there is no complete circuit, minus the capacitance effect). I have a counterexample for thinking this isn't the case: Let's say a "little bit" of charge flows to a piece of metal, if we, say, just touch the positive end of a AA battery to the metal. Now, this might seem reasonable if the piece of metal is an inch long piece of wire. But what if we take the limit, and say the piece of metal is 100 miles long? Does the wire just completely drain the battery to put it at the same potential? This seems unlikely to me. So, what is the answer? Should any charge flow, theoretically? Practically? Thanks!