Does a DC Cell or Battery Actually Supply Electrons?

[John Mohr]

I have held the assumption that batteries supply electrons at the negative terminal and absorb electrons at the positive end for many years. However, after watching this video at about 3:30, it is said that batteries do not actually supply charged particles but that the battery only creates an electric field which pushes the charged particles along. Is this correct?

 

[Dale]

Is there a difference?

 

[John Mohr]

Is there a difference?

I guess to add a Shakespearian flare, "...to supply or not supply, that is the question". In other words, is there a source of charged particles coming from the battery or not? This video seems to suggest that there are no electrons coming out of the battery.

 

[kuruman]

Just to clarify, are you asking whether the battery is a source of new electrons? The answer to that is no, the battery does not create electrons. Remember that a circuit connected to a battery is electrically neutral. Crudely speaking, electrons come in with low potential energy and leave the battery with high potential energy.

 

[Dale]

I guess to add a Shakespearian flare, "...to supply or not supply, that is the question". In other words, is there a source of charged particles coming from the battery or not? This video seems to suggest that there are no electrons coming out of the battery.

Electrons come out of the - terminal and go in the + terminal.

 

[John Mohr]

Just to clarify, are you asking whether the battery is a source of new electrons? The answer to that is no, the battery does not create electrons. Remember that a circuit connected to a battery is electrically neutral. Crudely speaking, electrons come in with low potential energy and leave the battery with high potential energy.

Mmm... I must not be understanding something here quite right. When you say 'new' in the first question above, I would have assumed yes because in order for there to be a current, there has to be some input for that current. This current then ends up at the positive terminal where the electrons enter the battery.

 

[John Mohr]

Electrons come out of the - terminal and go in the + terminal.

Yes, this is what I have thought as well, but the video clip seems to say something different.

 

[DaveE]

The video is wrong. Consider electroplating as a counter example.

 

[Ibix]

The video, at least at the linked time stamp, doesn't say electrons don't come out of the terminal. It just says the battery doesn't create charged particles, which is correct.

 

[vanhees71]

First of all electric charge is strictly conserved. If it were not the entire edifice of classical electrodynamics wouldn't make sense, because it's a gauge theory, and the strict conservation of electric charge is an "integrability condition" for Maxwell's equations (due to Noether's 2nd theorem).

If looked at the first few minutes of the video, and seems at least not to be entirely wrong. Of course, it's inaccurate in claiming that there's some voltage in batteries, though it's an electromotive force, but that subtlety is perhaps asked for too much for such a Youtube video.

A good textbook on physical chemistry is for sure a better source to understand what's going on in a voltaic cell/battery.

 

[sophiecentaur]

Of course, it's inaccurate in claiming that there's some voltage in batteries,

Not 'inaccurate', so much as 'incomplete'. The Voltage that the battery can supply (Joules per Coulomb delivered) is modified by the Current (Coulombs per second) flowing though and will always be less than the so-called electromotive force. The EMF is the limiting voltage as the current approaches zero and when no energy is lost in the battery. The (again, so-called) Internal Resistance of the battery is a term used for the mechanism for the internally lost Power (I²R₀). The mechanism can be treated as a small series resistance but is not actually constant for all values of current but is near enough for Jazz. You cannot 'look inside' a cell and measure the emf under load. It's all just a handy model - as are many of the Equivalent Circuits we use in EE.

 

[hutchphd]

It's all just a handy model - as are many of the Equivalent Circuits we use in EE.

I think this needs to be reiterated. The Thevenin equivalent ideal battery (ideal source+ series resister) is no more "physical" than the Norton equivalent (ideal source + parallel resister) . Many folks wander off the garden path by believing the model is reality.
My cognitive battery model involves elves laboring to carry small blue electrons up the potentiaal hill...this way I don't invest in its reality to my detriment.

 

[vanhees71]

As leptons electrons are colorless though, but that's another story.

 

[sophiecentaur]

FI think this needs to be reiterated.
My cognitive battery model involves elves laboring to carry small blue electrons up the potentiaal hill...this way I don't invest in its reality to my detriment.

That’s a sign of a very elfie attitude. (Sorry)

 

[Baluncore]

My cognitive battery model involves elves laboring to carry small blue electrons up the potentiaal hill...this way I don't invest in its reality to my detriment.

I am also convinced that there were three elves wearing space suits, in the cathode of every colour CRT. Their job was to select only the red, green or the blue coloured electrons, then load them into the appropriate gun.

 

[sophiecentaur]

three elves wearing space suits, in the cathode of every colour CRT.

I had great problems stopping the lovely James Burke (of BBC TV fame) from talking on air about red green and blue electrons in one of his series. He did listen to me eventually and never spoke those words. They did, at least, use Scientific advisors for his programmes. No absolute howlers went out (not that I noticed)

 

[anorlunda]

I am also convinced that there were three elves wearing space suits, in the cathode of every colour CRT.

Not elves, but Maxwell's Demons.

 

[hutchphd]

That’s a sign of a very elfie attitude. (Sorry)

Breaftakingly bad. 'earty congratulations.

 

[gmax137]

I have a new mental model of the electrons lined up in the battery

 

[hmmm27]

<tsk> Everybody knows that electrons are black and protons are red.

 

[davenn]

we seem to have lost the OP

@John Mohr are you on the right track now ?

 

[John Mohr]

Yes, sorry @davenn - I certainly appreciate the answer posts (and the jovial banter too). Thanks for sharing your thoughts. Although the video seemed good in some ways, it seemed a little misleading at the point where it talked about electrons not being emitted from the negative terminal at 3:30. This clears things up. Much appreciated @Dale @kuruman @DaveE @vanhees71 @Ibix @sophiecentaur @hutchphd @Baluncore and other posters.