Does electricity have momentum?

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    Electricity Momentum
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Discussion Overview

The discussion revolves around the concept of whether electricity possesses momentum, drawing comparisons to fluid dynamics, particularly water flow in pipes. Participants explore the implications of momentum in electrical circuits and how it relates to current flow and potential differences.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants suggest that if electricity behaves like water in a pump system, then current might be higher at certain points due to momentum, similar to pressure and flow in water.
  • Others argue that bending wires in a circuit does not affect voltages and currents, emphasizing that energy flows in response to potential differences rather than the physical layout of the circuit.
  • One participant notes that while moving charges do have momentum, it is generally inconsequential in most circuits.
  • There is a discussion about the uniform flow of water in pipes, with some questioning how flow rates could differ in a uniform-diameter pipe, suggesting that bending the pipe could lead to laminar or turbulent flow.

Areas of Agreement / Disagreement

Participants express differing views on the relevance of momentum in electricity, with some asserting its inconsequential nature in circuits while others draw parallels to fluid dynamics. The discussion remains unresolved regarding the implications of momentum in electrical contexts.

Contextual Notes

Participants rely on analogies between fluid dynamics and electrical flow, which may introduce limitations in understanding the complexities of electrical circuits. The discussion highlights assumptions about the behavior of charges and energy flow in circuits.

BenChicago
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w = x = y = z ,

If this were a pump system with water, I think the pressure and flow would be much higher at reading #2, because water has momentum? What about electricity, would the current be higher at #2?
 

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If you create a circuit, and then bend the wires around in arbitrary ways, you will not change anything about the voltages and currents.

Charges have momentum, and of course charges have to move for electricity to flow, but it isn't as simple as the case of water (part of the reason the analogy is bad). If current flows from one end of a wire to the other, there is no electron that traveled that whole distance. Energy is flowing in response to potential differences, and (assuming the wire has no resistance) it doesn't matter what the wire does between points A and B, just the potential at the two points. That's why you can draw schematic circuit diagrams without worrying about the actual layout of items in space.
 
BenChicago said:
w = x = y = z ,

If this were a pump system with water, I think the pressure and flow would be much higher at reading #2, because water has momentum? What about electricity, would the current be higher at #2?

How could the water flow be different at different parts of the uniform-diameter pipe? Water is basically incompressible, so the flow rate has to be uniform in that uniform pipe.
 
berkeman said:
How could the water flow be different at different parts of the uniform-diameter pipe? Water is basically incompressible, so the flow rate has to be uniform in that uniform pipe.

I think he's thinking if you bend the pipe, water will have laminar or turbulent flow and all that?
 
Yes, moving charges do have momentum. But it is inconsequential in most circuits.
 

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