Power relation to lightbulb wattage

[nmsurobert]

Power is measured in watts and lightbulbs are rated in watts.

P = W/t
and
W = Fd
What is being displaced? electrical current?

 

[anorlunda]

Don't try to make that direct comparison between electrical energy and mechanical energy. Electrons in wires do move, but their behavior is very different than say bowling balls, so the comparison only confuses.

Think of a chemical reaction that also produces energy. You mix two things and it gets hot. You wouldn't ask what is being displaced in that case would you?

 

[russ_watters]

Power is measured in watts and lightbulbs are rated in watts.

P = W/t
and
W = Fd
What is being displaced? electrical current?

Electrical energy (not current) is converted to heat.

Edit: sorry, not on point.
W=fd applies to a specific kind of mechanical work only. It does not apply here.

 

[nmsurobert]

ah ok. that makes sense thanks, guys!

 

[OmCheeto]

Power is measured in watts and lightbulbs are rated in watts.

P = W/t
and
W = Fd
What is being displaced? electrical current?

Yes [edit: speaking laymanishy, that is]

 

[CWatters]

For electrical energy...

W=V*I

Aside: light bulbs should be rated in Lumens and Watts.

 

[OmCheeto]

For electrical energy...

W=V*I

...

?
This makes it look like "W" = "work" which is sometimes "energy" = volts * amps, which is not correct.
Guessing you meant "W" = "watts", which is power, which is not energy.
?

 

[OmCheeto]

Yes [edit: speaking laymanishy, that is]

I tried explaining this about 6 years ago. My post got no acknowledgments, and looking back on it now, I can understand why, as it's all very complicated.

Here's my latest attempt.

It's still lacking, IMHO.

 

[anorlunda]

@OmCheeto as you noted, the electrons move only a small distance (not arbitrary but small). That makes the whole analogy unhelpful. Too many students visualize electrons in a wire to be like ball bearings in a pipe, and energy like a bucket collecting ball bearings at the end of the pipe. We should discourage that.

 

[OmCheeto]

@OmCheeto as you noted, the electrons move only a small distance (not arbitrary but small). That makes the whole analogy unhelpful. Too many students visualize electrons in a wire to be like ball bearings in a pipe, and energy like a bucket collecting ball bearings at the end of the pipe. We should discourage that.

hmmm...
It may take me another 6 years to incorporate your comments into a useful analogy.
But I'm in no rush.

ps. Electrons are like ball bearings in a pipe, IMHO. They're just a bit more squishy, and have arms that stick out, to slap people on the butt, while driving by in the car.

hmmm... Where's @Drakkith when I need him?

OmCheeto; "Electricity is like a woman having a baby. It's kind of squishy, and there's a lot of force involved. And then she has about a bazillion more babies. Only, she has to eat her babies. And then, everyone argues, how she did that."​

hmmmm...
It may be another 12 years before I develop an adequate analogy.

 

[CWatters]

?
This makes it look like "W" = "work" which is sometimes "energy" = volts * amps, which is not correct.
Guessing you meant "W" = "watts", which is power, which is not energy.
?

Yes sorry I mean W as in Watts.

Energy = power * time

 

[Drakkith]

ps. Electrons are like ball bearings in a pipe, IMHO. They're just a bit more squishy, and have arms that stick out, to slap people on the butt, while driving by in the car.

hmmm... Where's @Drakkith when I need him?

I can't help you on your analogies, Om. I'm out slapping electron butts.

Besides, I prefer to think of electrons in a wire as if they were a plethora of pushy particles perpetually pinging around a lazily lounging little lattice.

 

[sophiecentaur]

ps. Electrons are like ball bearings in a pipe, IMHO. They're just a bit more squishy,

No. Not ballbearings because that would imply that their mass is relevant. It is not. Go for very rigid polystyrene balls instead and that would imply they have almost zero Kinetic Energy. (Mass of the electrons in a wire is about 1/100,000 of the actual wire mass)
On PF we should be trying to lay all those ghosts of bad Science that people are presented with from their earliest years.

 

[Tom.G]

trying to lay all those ghosts

I'm still trying to figure out how that would work.

 

[sophiecentaur]

I'm still trying to figure out how that would work.

We can only do our best.

 

[OmCheeto]

No. Not ballbearings because that would imply that their mass is relevant. It is not. Go for very rigid polystyrene balls instead and that would imply they have almost zero Kinetic Energy. (Mass of the electrons in a wire is about 1/100,000 of the actual wire mass)
On PF we should be trying to lay all those ghosts of bad Science that people are presented with from their earliest years.

Ok. But in my defense, I did say;

It may be another 12 years before I develop an adequate analogy.

Though, I think that is overly optimistic.
Maybe in my next lifetime.

Btw, my main point was to try and reconcile the "meter" thing. Everything else is just bad analogy.
Not sure if you remember, but I voiced an interest in writing an insights article a while back, on "How and why the electrostatic chicken crossed the road".
After numerous attempts, I decided it was a rabbits hole, from whence I would never escape.
Basically, I decided it would just be a transliteration of the electromagnetism portion from my college text. A story full of bizarre roosters and hens, wielding sticks, and being surround[ed] by bees. But the bees only show up if the chickens move.

Ehr mehr gerd...

edit: I get excited, and misspell things, when that happens.

 

[sophiecentaur]

"How and why the electrostatic chicken crossed the road".

I guess the result would have been a Cross Product of the variables Chicken and Road. (Chicken's name was Victor - or Vector)

 

[dlgoff]

Electrons in wires do move, but their behavior is very different than say bowling balls, ...

Differently indeed.
From Microscopic View of Ohm's Law:

 

[OmCheeto]

I guess the result would have been a Cross Product of the variables Chicken and Road. (Chicken's name was Victor - or Vector)

I've heard it said, that you will never understand anything about electromagnetism, until you understand Maxwell's equations.

The dot products I can only approximate to spring-like poking sticks, and the cross products I can only relate to a hive of bees, buzzing around, in a most peculiar way, really pissed off, at the person trying to describe them.

 

[sophiecentaur]

I've heard it said, that you will never understand anything about electromagnetism, until you understand Maxwell's equations.

The dot products I can only approximate to spring-like poking sticks, and the cross products I can only relate to a hive of bees, buzzing around, in a most peculiar way, really pissed off, at the person trying to describe them.

I must say, I find your correspondences very refreshing and not a little confusing. There are some rather po-faced contributors to PF and you are definitely not one of them. Don't ever stop - even if the mods whup yo' ass.