Are charged batteries heavier than dead ones?

HuntingPudel

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E=mc^2 is just a specific case of E=mv^2, where we are replacing the variable for velocity with a constant (the speed of light). It is a solution for the amount of energy required for an object of a given mass to travel at a given velocity. It is totally incorrect to be used in the situation of potential energy, given no velocity.
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CHeil402

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It would be a simple experiment requiring no calculation of weight at all with identical batteries. Put a discharged battery and a fully charged battery on opposing sides of a balance beam. Now, charge the dead battery with the full one til they match charges.

I'd love to find that, surely someone with access to a lab has done it.
There are no scales precise enough to perform this and that's the whole point here. Technically a full battery weighs more... BUT not to a measurable extent by any tools currently available. The difference in the weight wouldn't be able to overcome static friction in the scales. It's a fun though experiment; technically it weighs less... practically, it doesn't.

This is similar to trying to see if you weigh less after blinking your eyes. It took energy to blink so technically you weigh less, but not to an extend you can observe / measure.

This reminds me of a definition of 'forever'. Imagine a tall mountain that once a year an eagle flies over it and brushes its wing against the tip of the mountain. Technically that interaction had friction which wore down the top of the mountain. The amount of time it would take for the mountain to be reduced to level ground through this process is 'forever'. Technically it would eventually happen (ignoring geological processes), but it's after an immeasurable amount of time.
 
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Carsinmyblood

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There are no scales precise enough to perform this and that's the whole point here. Technically a full battery weighs more... BUT not to a measurable extent by any tools currently available. The difference in the weight wouldn't be able to overcome static friction in the scales. It's a fun though experiment; technically it weighs less... practically, it doesn't.

This is similar to trying to see if you weigh less after blinking your eyes. It took energy to blink so technically you weigh less, but not to an extend you can observe / measure.

This reminds me of a definition of 'forever'. Imagine a tall mountain that once a year an eagle flies over it and brushes its wing against the tip of the mountain. Technically that interaction had friction which wore down the top of the mountain. The amount of time it would take for the mountain to be reduced to level ground through this process is 'forever'. Technically it would eventually happen (ignoring geological processes), but it's after an immeasurable amount of time.
Wait a minute! Supposing two swallows were tied together with a bit of string?
 


timbop

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Using E=mc^2 assumes the electrons are being consumed (converted into energy), but they’re not. They’re just moving from one place in the battery to another. The energy consumed is the return of potential energy put into the battery by the charger.
exactly. The electrons move from one terminal of the cell to the other. They don't get consumed in any way, which is why there is no exhaust pipe.

The number of particles in the battery does not change, and neither does its mass.
 

TheCats

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exactly. The electrons move from one terminal of the cell to the other. They don't get consumed in any way, which is why there is no exhaust pipe.

The number of particles in the battery does not change, and neither does its mass.
The argument is that molecules with electrons in lower shells have infinestimal less mass than the same atoms in different molecules with a higher energy state.

This is almost a theoretical argument because the difference in mass is too small to measure. We 'know' it because the most accepted theory says that it's true. Despite that same theory not having a good way to be reconciled with gravity.
 
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Carsinmyblood

Carsinmyblood

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Simply put - electrons don't weigh much.
....but they can knock you down.... or more accurately, cause you to involuntarily test the laws of gravity in your immediate vicinity.
 

JoeDimwit

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Alright… let’s just go ahead and keep all the S.T.E.M. malarkey off my automobile forum. Kthanks. ?
 
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Carsinmyblood

Carsinmyblood

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Alright… let’s just go ahead and keep all the S.T.E.M. malarkey off my automobile forum. Kthanks. ?
Pretty sure the S.T.E.M. geeks got us here in the first place.

Let's give them their due, and a big bag of Cheezy-Poofs.??
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