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Electroboom: How Right IS Veritasium?! Don't Electrons Push Each Other??
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electrodacus:

--- Quote from: hamster_nz on June 30, 2022, 11:18:59 pm ---And yet the oscilloscope on Derek's experiment voltage at the bulb before the bulk of the voltage can flow around the full length of the wire/pipe... so it either when along the wire/pipe at faster than light speeds, or the energy went across the 1m gap.

Or I guess you can argue that the experimental method was flawed, because it is inconsistent with your expectations.

--- End quote ---

The result is perfectly correct the explanation and conclusion from what he seen is false as he completely ignores the line capacitance (capacitor is an energy storage device).
In fact he ignores energy storage in all his videos and gets to wrong conclusion because of that.


As I mentioned even if you just move the switch without closing the circuit you change the switch capacitance that will result in current flow (stream of electrons) and since charge reorganises it will affect the lamp and wires connected to it.
But that is mechanical energy that you input in the system by moving the switch contacts in space and it is not energy delivered by the battery.

You will need to put in energy in order to move the switch contacts apart. That mechanical energy is converted in to electrical energy with a part of it charging the battery and another part ending radiated as thermal energy heating the wire due to wire resistance.
When you let go of the switch so that the switch is pulled back to original position by the electric field force and so you again have electron flow this time leaving the battery and also part of it ending up as heat in the wire later all this thermal stored energy is radiated as electromagnetic waves in the infrared spectrum.

Battery or better example charged capacitor will end up with exact same amount of energy it started with and all the mechanical energy you provided ended up as electromagnetic radiated energy maybe even a bit in the visible spectrum if the lamp filament could glow with the amount of input energy (not realistic with moving a small switch with low capacitance).

You will observe the same exact behaviour as in Derek's experiment when he closed the switch (same oscilloscope waveform) if you had a sensitive enough scope to measure that smaller voltage drops.

I also showed the spice simulation with the exact same waveform that Derek got if you remember that.
electrodacus:

--- Quote from: hamster_nz on June 30, 2022, 11:47:05 pm ---Does a 10kg bowling ball at 10m above the ground "have" potential energy? Or does it have the potential to gain that energy if you let it fall 10m?

It depends on the definition of 'h' in the gravitational potential energy formula of U=mgh. Height isn't an absolute thing, it is measured between two points.

If I move that bowling ball slightly to the right, where there might be a 10m deep well... has it suddenly gained twice as much potential energy just from me moving it less than a meter? In the formula 'm' and 'g' stays the same, but 'h' has changed because the reference point for the measurement has changed.

--- End quote ---


Yes the 10kg ball at 10m above ground has potential energy relative to that point you selected on the ground same as you can select a different ground in an electric circuit to reverence to.
When moved above the well the potential energy relative to the bottom of the well will be higher than potential energy relative to the ground.
When you drop that ball on the ground that potential energy will end up as heat and maybe some plastic deformation.  There will be twice as much heat if you drop it into the well.  You will also need to put in energy to lifted back to ground level.
 


--- Quote from: hamster_nz on June 30, 2022, 11:47:05 pm ---If I am on a train travelling at 100km/h and drop a bowling ball on my foot, does it hurt more than when the train is stopped, even though when the train is in motion the ball is travelling at over 27m/s?

I guess you could chose to use the earth's surface as reference point for kinetic and electrical energy (making the assumption that the Earth is electrically neutral and stationary), and you could use the center of the Earth as your reference point to give a more 'absolute' measure of gravitational potential energy.

That may work for you, unless perhaps you are in the business of launching bowling balls into the sun, in which case they have far more kinetic and potential energy than those calculation would suggest...  :-//

EDIT: on second thoughts, maybe you can establish of what electrically "neutral" is using electrostatic attraction/repulsion, I guess, but would be pretty hard to achieve a useful reference for single digit voltages...

--- End quote ---


Yes it will hurt more if the train travels up than if it stands still or travels down (falling towards earth).
Naej:

--- Quote from: hamster_nz on June 30, 2022, 11:47:05 pm ---
--- Quote from: Naej on June 30, 2022, 11:16:03 pm ---If you deny potential energy, what other forms of energy do you deny?
Here's a list: https://en.wikipedia.org/wiki/Energy

--- End quote ---

Does a 10kg bowling ball at 10m above the ground "have" potential energy? Or does it have the potential to gain that energy if you let it fall 10m?

It depends on the definition of 'h' in the gravitational potential energy formula of U=mgh. Height isn't an absolute thing, it is measured between two points.

If I move that bowling ball slightly to the right, where there might be a 10m deep well... has it suddenly gained twice as much potential energy just from me moving it less than a meter? In the formula 'm' and 'g' stays the same, but 'h' has changed because the reference point for the measurement has changed.

Things like how many kJ are in your sandwich (chemical potential energy), or how many megatons of TNT are in your warhead (nuclear potential energy) don't change just because you move your lunchbox by 1m or launch your missile. Some measures like kinetic, electrical and gravitational potential energy depend on what chosen reference for "zero energy" is.

If I am on a train travelling at 100km/h and drop a bowling ball on my foot, does it hurt more than when the train is stopped, even though when the train is in motion the ball is travelling at over 27m/s?

I guess you could chose to use the earth's surface as reference point for kinetic and electrical energy (making the assumption that the Earth is electrically neutral and stationary), and you could use the center of the Earth as your reference point to give a more 'absolute' measure of gravitational potential energy.

That may work for you, unless perhaps you are in the business of launching bowling balls into the sun, in which case they have far more kinetic and potential energy than those calculation would suggest...  :-//

EDIT: on second thoughts, maybe you can establish of what electrically "neutral" is using electrostatic attraction/repulsion, I guess, but would be pretty hard to achieve a useful reference for single digit voltages...

--- End quote ---
All energies are relative yes. Including chemical ( https://en.wikipedia.org/wiki/Standard_enthalpy_of_formation ).
Does it mean you deny all forms of energy exist?
hamster_nz:

--- Quote from: Naej on July 01, 2022, 12:40:51 am ---Does it mean you deny all forms of energy exist?

--- End quote ---
Of course not. I am of the view that some forms of energy can be attributed of the thing (e.g. kJ in a sandwich, energy stored in a spring, energy in a capacitor), but other forms of energy cannot be determined without reference to the wider environment or the larger system around it (e.g. a bowling ball on a moving train has different kinetic energy when calculated with reference to the train, or the ground under the train).

Likewise for an electron drifting along in a current carrying wire. It has a small amount of kinetic energy, but my view is how much work that electron can do depends on the electric field outside of the wire.

Take this poorly drawn ASCIIart circuit:

--- Code: ---
 +----+
 |    |
 |    \
---   /  10 ohm
 -    \
 |    |
 +----+--> GND
 |    |
 |    \
---   /  10 ohm
 -    \
 |    |
 +-----

--- End code ---
The top battery is supplying electrons (and power) to the top resistor, the bottom battery is supplying electrons (and power) to the bottom resistor. There is zero net current in the center wire, the one connected to GND.

What happens when the middle wire is removed?


--- Code: ---
 +----+
 |    |
 |    \
---   /  10 ohm
 -    \
 |    |
 |    +--> GND
 |    |
 |    \
---   /  10 ohm
 -    \
 |    |
 +----+

--- End code ---
Do the electron leaving the bottom battery's negative terminal suddenly realize that they have to do twice the work (pass through both resistors), so carry twice the energy for the trip? What about those electrons already in transit? Do they use up their energy and stop half way?  This is a problem if you believe that the electrons are responsible for transferring the energy.

Are any of the voltages or currents any different than before? If not, how can the electrons carry more energy?
electrodacus:

--- Quote from: hamster_nz on July 01, 2022, 02:54:30 am ---
Likewise for an electron drifting along in a current carrying wire. It has a small amount of kinetic energy, but my view is how much work that electron can do depends on the electric field outside of the wire.

Take this poorly drawn ASCIIart circuit:

--- Code: ---
 +----+
 |    |
 |    \
---   /  10 ohm
 -    \
 |    |
 +----+--> GND
 |    |
 |    \
---   /  10 ohm
 -    \
 |    |
 +-----

--- End code ---
The top battery is supplying electrons (and power) to the top resistor, the bottom battery is supplying electrons (and power) to the bottom resistor. There is zero net current in the center wire, the one connected to GND.

What happens when the middle wire is removed?


--- Code: ---
 +----+
 |    |
 |    \
---   /  10 ohm    (A)
 -    \
 |    |
 |    +--> GND
 |    |
 |    \
---   /  10 ohm     (B)
 -    \
 |    |
 +----+

--- End code ---
Do the electron leaving the bottom battery's negative terminal suddenly realize that they have to do twice the work (pass through both resistors), so carry twice the energy for the trip? What about those electrons already in transit? Do they stop half way?

Are any of the voltages or currents any different than before?

--- End quote ---

There is no difference between those two circuits. Due to symmetry no electrons will travel through that middle wire.
As far as that circuit is concerned is like having two batteries in series so 2x the voltage connected to a 20Ohm resistor.

To better see what happens use charged capacitors instead of batteries.
Say each capacitor starts with 300 electrons on one plate and 100 electrons on the opposite plate.

100 electrons will leave the charged plate of capacitor A (the one that started with 300) and get to the plate that has a deficit on capacitor B
The end result will be two discharged capacitors with 200 electrons on each plate.
All that stored energy will end up dissipated on the resistors/wires.
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