Why is the flow rate constant in a circuit with two resistors?

[Antiphon]

There needs to be a permanent sticky article that adresses this. It comes up over and over.

 

[sophiecentaur]

The analogy is excellent. You can use the intertia of water to make inductors where there is an induced pressure across a pipe section due to the time derivative of the flow. In fact you can build a real water-and-pipe transformer! It works by eletrogravitational induction (too weak to measure except by gravity probe B but real nonetheless).

I can't say that recommends itself to the would-be elementary student of electrical theory then. Correct as it may be, it sounds like a great way of distracting from a simple appreciation of Ohm's laws and others we learn in college!
I'm not sure that "analog" and "analogy" are universally or strictly the way round that you claim.

I wonder whether we should have a grading system which we could apply to our posts, corresponding to the level they come from and where they're aimed. (Where they're aimed, in particular)

 

[mikeph]

As is often the case, the main problem with the water analogy is that people don't understand the fluid dynamics part and thus apply it wrong:
There isn't one type of pressure, there are three in the most common form of Bernoulli's equation. The relevant pressure here is total pressure and Bernoulli's principle, simply stated, is that total pressure is constant along a streamline. It is often the case that people drop the one-word qualifier stating which pressure they are talking about. In the case of a venturi tube, it is static pressure that drops, but velocity pressure rises, keeping total pressure constant.

Even more important, none of this has any relevance to the water/electricity analogy, since the most common form of Bernoulli's equation is a conservation of energy statement, so it isn't saying anything about energy dissipation. It's not a restriction that is needed for the description, but a device to dissipate flow energy. This dissipation of flow energy shows up as a decrease in total pressure (ie, voltage) for a certain constant flow rate (ie, amperage).

I try to explain my thoughts on the subject but they are often not fully developed, I guess the issue requires more thought than I gave!

Thanks for the help.