6 ms·

I generally found the fluid analogy did more damage than good for a lot of people in EE school. A lot of people think of electricity as electrons zipping around

by mbell 8y ago

I generally found the fluid analogy did more damage than good for a lot of people in EE school. A lot of people think of electricity as electrons zipping around a circuit at the speed of light due (at least in part) to the water analogy. Having to transition from that world to thinking in charge transfer and fields while electrons move around linearly at a snails pace if at all was very difficult for many people. I'd bet in a poll of the general public, most people think electrons fly around a circuit like water in a pipe, which is of course completely wrong. I guess it's debatable whether the inaccuracy matters or not. But in general, I prefer analogies that are simplifications and leave out details, rather than those that are completely ass backwards from reality.

neuralRiot 8y ago
The way the analogy was explained to me when i was a student is that the conductor is a hose filled with water, when you open the valve the water comes out instantly at the other end because the "charge" is moving. It was never confusing to me.
- jcims 8y ago
  I think anyone that has waited for hot water to get to the tap understands this. Pressure (voltage) transmits at the speed of sound (light). The speed of the particles through the medium, on the other hand, depends on many factors.
- hexane360 8y ago
  This is the correct way. In the water analogy, the circuit is a closed system and components are completely filled with water at all times. For example, the capacitor is a filled sphere with a rubber divider. The total amount of charge/water is constant, but you can change how it is divided between the two plates by an applied voltage/pressure.
- fjsolwmv 8y ago
  The analogy is valid and hydraulic circuits work. If people transfer their incorrect understanding of water to incorrect knowledge of electricity, that doesn't make the analogy bad.
- mbell 8y ago
  I think the analogy can work, but needs to be carefully applied. This wasn't an analogy taught in my EE program, but one that is common in TV programming and provided by high school science teachers whom may not themselves understand the nuance so many came into the program with this understanding in place. Ultimately though, this concept was the breaking point for my EE class; It's when half the class dropped out to other majors. Not that I blame the analogy entirely for this, I think in general this is the point at which a lot of people lose connection with deeper sciences. It's the point where analogies to the physical world (matter) break down because we're now fundamentally talking about energy, which doesn't obey the rules all humans are accustom to. The world where we can't see it or relate it to our daily experiences but only talk about it through mathematics.
codeflo 8y ago
That's an interesting experience. I'd say that the idea people have about water in pipes is probably overly simplistic as well, and an analogy to an equally poorly understand concept can't help very much. To pick up your example about electron speed vs. signal speed: Water pressure is transmitted at the speed of sound, which is much, much higher than the speed of water flow -- water taps wouldn't work otherwise.
deleted 8y ago
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by mbell 8y ago

neuralRiot 8y ago

The way the analogy was explained to me when i was a student is that the conductor is a hose filled with water, when you open the valve the water comes out instantly at the other end because the "charge" is moving. It was never confusing to me.

jcims 8y ago
I think anyone that has waited for hot water to get to the tap understands this. Pressure (voltage) transmits at the speed of sound (light). The speed of the particles through the medium, on the other hand, depends on many factors.
hexane360 8y ago
This is the correct way. In the water analogy, the circuit is a closed system and components are completely filled with water at all times. For example, the capacitor is a filled sphere with a rubber divider. The total amount of charge/water is constant, but you can change how it is divided between the two plates by an applied voltage/pressure.
fjsolwmv 8y ago
The analogy is valid and hydraulic circuits work. If people transfer their incorrect understanding of water to incorrect knowledge of electricity, that doesn't make the analogy bad.
mbell 8y ago
I think the analogy can work, but needs to be carefully applied. This wasn't an analogy taught in my EE program, but one that is common in TV programming and provided by high school science teachers whom may not themselves understand the nuance so many came into the program with this understanding in place. Ultimately though, this concept was the breaking point for my EE class; It's when half the class dropped out to other majors. Not that I blame the analogy entirely for this, I think in general this is the point at which a lot of people lose connection with deeper sciences. It's the point where analogies to the physical world (matter) break down because we're now fundamentally talking about energy, which doesn't obey the rules all humans are accustom to. The world where we can't see it or relate it to our daily experiences but only talk about it through mathematics.

codeflo 8y ago

That's an interesting experience. I'd say that the idea people have about water in pipes is probably overly simplistic as well, and an analogy to an equally poorly understand concept can't help very much. To pick up your example about electron speed vs. signal speed: Water pressure is transmitted at the speed of sound, which is much, much higher than the speed of water flow -- water taps wouldn't work otherwise.

deleted 8y ago

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