Electricity doesn't work the way I thought it did
Discussion
Veritasium taking on another topic after killing my brain with "Faster than the wind downwind"
https://youtu.be/bHIhgxav9LY
https://youtu.be/bHIhgxav9LY
I used to work with a bloke who was known to be an obsessive penny-pincher. Tighter than two coats of paint and all that sort of thing.
One day at work he started going on about how he hated using those 20 or 30m extraction reels around the home for DIY or gardening because he said they 'wasted electricity'. He went on to say that the long reel of wire 'fills up with electric' like water filling a long hosepipe, and then when you unplug them all that electric just stays in the reel of wire and gets wasted, like excess water slowly leaking out of a turned off hosepipe.
He then asked if there was a way to calculate how much electricity, in money terms, was 'still in the extension reel after it was unplugged'. He also said he went mad if anyone left a socket turned on without a plug being inserted as 'electricity might leak out and be wasted'.
I had visions of him shouting "Who left this plug on? I came downstairs this morning and there was electricity all over the floor".
I mean, unnecessary use of long extension cables does 'waste' electricity. A long 30m or 50m reel can lose around 4-5% of the supplied energy in heat when used at the full 13amp rating, but the way he was suggesting they wasted electricity was quite funny
One day at work he started going on about how he hated using those 20 or 30m extraction reels around the home for DIY or gardening because he said they 'wasted electricity'. He went on to say that the long reel of wire 'fills up with electric' like water filling a long hosepipe, and then when you unplug them all that electric just stays in the reel of wire and gets wasted, like excess water slowly leaking out of a turned off hosepipe.
He then asked if there was a way to calculate how much electricity, in money terms, was 'still in the extension reel after it was unplugged'. He also said he went mad if anyone left a socket turned on without a plug being inserted as 'electricity might leak out and be wasted'.
I had visions of him shouting "Who left this plug on? I came downstairs this morning and there was electricity all over the floor".
I mean, unnecessary use of long extension cables does 'waste' electricity. A long 30m or 50m reel can lose around 4-5% of the supplied energy in heat when used at the full 13amp rating, but the way he was suggesting they wasted electricity was quite funny
GroundZero said:
I always thought of electricity as a similar case to "Newton's cradle", even though it was incorrectly taught at school to be more "river" like.
Recently saw that Veritasium video and it does puts another angle on it which is interesting.
Yeah, akin to pushing a rod. You don't have to push one end of the rod much for the end of the other end to move.Recently saw that Veritasium video and it does puts another angle on it which is interesting.
Kes Arevo said:
GroundZero said:
I always thought of electricity as a similar case to "Newton's cradle", even though it was incorrectly taught at school to be more "river" like.
Recently saw that Veritasium video and it does puts another angle on it which is interesting.
Yeah, akin to pushing a rod. You don't have to push one end of the rod much for the end of the other end to move.Recently saw that Veritasium video and it does puts another angle on it which is interesting.
Some of the extensions and rebuttals to the video are going to be interesting to watching. It seems like Veritasium's assumptions make it far more debateable than FTTWDW.
Biggest problem with this video (and topic) is that it's best explained mathematically, as it's so hard to imagine these EM fields and their energy transfer etc.
FWIW, I think the Newton's cradle of electrons idea is about the best easy-to-visualise explanation without field jiggery-pokery.
FWIW, I think the Newton's cradle of electrons idea is about the best easy-to-visualise explanation without field jiggery-pokery.
Lord Marylebone said:
I used to work with a bloke who was known to be an obsessive penny-pincher. Tighter than two coats of paint and all that sort of thing.
One day at work he started going on about how he hated using those 20 or 30m extraction reels around the home for DIY or gardening because he said they 'wasted electricity'. He went on to say that the long reel of wire 'fills up with electric' like water filling a long hosepipe, and then when you unplug them all that electric just stays in the reel of wire and gets wasted, like excess water slowly leaking out of a turned off hosepipe.
He then asked if there was a way to calculate how much electricity, in money terms, was 'still in the extension reel after it was unplugged'. He also said he went mad if anyone left a socket turned on without a plug being inserted as 'electricity might leak out and be wasted'.
I had visions of him shouting "Who left this plug on? I came downstairs this morning and there was electricity all over the floor".
I mean, unnecessary use of long extension cables does 'waste' electricity. A long 30m or 50m reel can lose around 4-5% of the supplied energy in heat when used at the full 13amp rating, but the way he was suggesting they wasted electricity was quite funny
One day at work he started going on about how he hated using those 20 or 30m extraction reels around the home for DIY or gardening because he said they 'wasted electricity'. He went on to say that the long reel of wire 'fills up with electric' like water filling a long hosepipe, and then when you unplug them all that electric just stays in the reel of wire and gets wasted, like excess water slowly leaking out of a turned off hosepipe.
He then asked if there was a way to calculate how much electricity, in money terms, was 'still in the extension reel after it was unplugged'. He also said he went mad if anyone left a socket turned on without a plug being inserted as 'electricity might leak out and be wasted'.
I had visions of him shouting "Who left this plug on? I came downstairs this morning and there was electricity all over the floor".
I mean, unnecessary use of long extension cables does 'waste' electricity. A long 30m or 50m reel can lose around 4-5% of the supplied energy in heat when used at the full 13amp rating, but the way he was suggesting they wasted electricity was quite funny
Wayoftheflower said:
If I thought about it much at all (Electrickery was by far my weakest subject) the chain in a pipe would've made the most logicial analogy in my mind. I guessed 2s for the circuit to "complete" and start delivering power.
Some of the extensions and rebuttals to the video are going to be interesting to watching. It seems like Veritasium's assumptions make it far more debateable than FTTWDW.
There is a video comment on this that suggests his solution is breaking the speed of light limitation, which is likely to be incorrect. Some of the extensions and rebuttals to the video are going to be interesting to watching. It seems like Veritasium's assumptions make it far more debateable than FTTWDW.
The idea that power is transmitted by the EM fields around the wire is pretty normal A level physics, but these would surely be established at the speed of light along the medium of conductance. The observation in the video comment was if you imagined someone with a pair of wire cutters at the far end of the wire. They cut the wire, and instantly the light goes out. Thus, you have transmitted information faster than the speed of light.
Wayoftheflower said:
Veritasium taking on another topic after killing my brain with "Faster than the wind downwind"
https://youtu.be/bHIhgxav9LY
That made my head hurt.https://youtu.be/bHIhgxav9LY
Dave Jones (EEVBlog) provides some clarity to the video with his excellent explanation.
https://www.youtube.com/watch?v=VQsoG45Y_00
https://www.youtube.com/watch?v=VQsoG45Y_00
The Poynting vector describes the flow of energy through a static EM field but the description in the video is not correct because the question is about a dynamic system (you are flipping the switch.) This is an electrodynamics problem and that means you need an equation that includes a "t" for time and, as you may have noticed, the pointing vector does not have a time variable.
The conclusion inferred in the video is that the shorts [the bits of wire going out into space] don't matter due to it acting as an antenna or capacitor or EM field. So imagine making one inconsequential topographic change and moving the switch to the end of the short, a half light second away from lamp and battery. Now when you flip the switch, a half second away from battery and lamp at light speed, the lamp would still turn on in 10^-9 seconds...right? So that would make the "signal" between the switch and lamp need to travel faster than the speed of light or violate causality.
Indeed what's so special about the switch, if it's just an antenna or capacitor or EM fields, why does the switch even need to be in the circuit? Would two bits of wire connected to a battery power every lamp in the world even if physically unconnected? Obviously not, of there is a break in the circuit current will not flow because there is no potential difference across the battery terminals.
Edit to add: Just to be clear I enjoyed the video. Sometimes being given the wrong answer is more interesting than the right answer because it makes you cognitively engage with the question. It is true to say that fields carry energy but fields are caused by moving charge, it's all chicken and egg.
The conclusion inferred in the video is that the shorts [the bits of wire going out into space] don't matter due to it acting as an antenna or capacitor or EM field. So imagine making one inconsequential topographic change and moving the switch to the end of the short, a half light second away from lamp and battery. Now when you flip the switch, a half second away from battery and lamp at light speed, the lamp would still turn on in 10^-9 seconds...right? So that would make the "signal" between the switch and lamp need to travel faster than the speed of light or violate causality.
Indeed what's so special about the switch, if it's just an antenna or capacitor or EM fields, why does the switch even need to be in the circuit? Would two bits of wire connected to a battery power every lamp in the world even if physically unconnected? Obviously not, of there is a break in the circuit current will not flow because there is no potential difference across the battery terminals.
Edit to add: Just to be clear I enjoyed the video. Sometimes being given the wrong answer is more interesting than the right answer because it makes you cognitively engage with the question. It is true to say that fields carry energy but fields are caused by moving charge, it's all chicken and egg.
Edited by speedy_thrills on Tuesday 14th December 00:18
Lord Marylebone said:
I used to work with a bloke who was known to be an obsessive penny-pincher. Tighter than two coats of paint and all that sort of thing.
One day at work he started going on about how he hated using those 20 or 30m extraction reels around the home for DIY or gardening because he said they 'wasted electricity'. He went on to say that the long reel of wire 'fills up with electric' like water filling a long hosepipe, and then when you unplug them all that electric just stays in the reel of wire and gets wasted, like excess water slowly leaking out of a turned off hosepipe.
He then asked if there was a way to calculate how much electricity, in money terms, was 'still in the extension reel after it was unplugged'. He also said he went mad if anyone left a socket turned on without a plug being inserted as 'electricity might leak out and be wasted'.
I had visions of him shouting "Who left this plug on? I came downstairs this morning and there was electricity all over the floor".
I mean, unnecessary use of long extension cables does 'waste' electricity. A long 30m or 50m reel can lose around 4-5% of the supplied energy in heat when used at the full 13amp rating, but the way he was suggesting they wasted electricity was quite funny
Doesn't electricity lose some energy when it goes along a wire? The longer the wire, the more the loss. There's also voltage drop as well. I remember a computer that wouldn't work when plugged in, via two or three extentions, out in the garden shed. In the house it worked fine. Lots of head scratching by those in the know who didn't know produced no results. I then tested everything. The voltage regulator was borderline, just manging enough in the house, close to the input, but with the various extensions, and the tortuous route the garage socket had to run, just put it below the cut off. One day at work he started going on about how he hated using those 20 or 30m extraction reels around the home for DIY or gardening because he said they 'wasted electricity'. He went on to say that the long reel of wire 'fills up with electric' like water filling a long hosepipe, and then when you unplug them all that electric just stays in the reel of wire and gets wasted, like excess water slowly leaking out of a turned off hosepipe.
He then asked if there was a way to calculate how much electricity, in money terms, was 'still in the extension reel after it was unplugged'. He also said he went mad if anyone left a socket turned on without a plug being inserted as 'electricity might leak out and be wasted'.
I had visions of him shouting "Who left this plug on? I came downstairs this morning and there was electricity all over the floor".
I mean, unnecessary use of long extension cables does 'waste' electricity. A long 30m or 50m reel can lose around 4-5% of the supplied energy in heat when used at the full 13amp rating, but the way he was suggesting they wasted electricity was quite funny
Current in wire also produces a magnetic field. That must take energy as well.
Yes, you get voltage drop as a result of resistance of the wire. It doesn't typically make a difference but if you're running multiple extension the voltage drop was probably beyond the lower threshold for the PC power supply.
If you want to watch shed porn or AvE you'll need a lower resistance cable or a way of increasing the voltage to with spec.
If you want to watch shed porn or AvE you'll need a lower resistance cable or a way of increasing the voltage to with spec.
Derek Smith said:
Doesn't electricity lose some energy when it goes along a wire? The longer the wire, the more the loss. There's also voltage drop as well. I remember a computer that wouldn't work when plugged in, via two or three extentions, out in the garden shed. In the house it worked fine. Lots of head scratching by those in the know who didn't know produced no results. I then tested everything. The voltage regulator was borderline, just manging enough in the house, close to the input, but with the various extensions, and the tortuous route the garage socket had to run, just put it below the cut off.
Current in wire also produces a magnetic field. That must take energy as well.
That must have been one long extension lead, or a very thin one. Or you were drawing an extraordinarily high current!Current in wire also produces a magnetic field. That must take energy as well.
Either the above - or your mains voltage was extremely low - as most PCs will function down to around 200v or so, depending on the quality of the PSU.
This guy (Alphapheonix channel), does the best job so far in explaining the veritasium video.
https://www.youtube.com/watch?v=2Vrhk5OjBP8
The graphics used in the video do a good job of visualising how the electric charge from one wire passes over to the other in order to provide a short lived current through the bulb.
https://www.youtube.com/watch?v=2Vrhk5OjBP8
The graphics used in the video do a good job of visualising how the electric charge from one wire passes over to the other in order to provide a short lived current through the bulb.
GroundZero said:
This guy (Alphapheonix channel), does the best job so far in explaining the veritasium video.
https://www.youtube.com/watch?v=2Vrhk5OjBP8
The graphics used in the video do a good job of visualising how the electric charge from one wire passes over to the other in order to provide a short lived current through the bulb.
That's a great video thanks for the link, particularly the "cut-wire" test around 18:00. I feel slightly less confuzzled than I did before.https://www.youtube.com/watch?v=2Vrhk5OjBP8
The graphics used in the video do a good job of visualising how the electric charge from one wire passes over to the other in order to provide a short lived current through the bulb.
I'm going to enjoy catching up on his other videos too, looks like another great science YT channel.
Well here's my stupid question having watched the first video:
If the power is going around the wire in the fields then why does a fuse wire blow? Surely the power is just in the field around it?
I was taught that DC and LF power went through the wire itself but as frequency increased it tended to go through the skin of the wire (skin effect) hence why some good quality high frequency wires were gold coated etc. This video suggest that even DC power goes through the fields and not the wire.
If the power is going around the wire in the fields then why does a fuse wire blow? Surely the power is just in the field around it?
I was taught that DC and LF power went through the wire itself but as frequency increased it tended to go through the skin of the wire (skin effect) hence why some good quality high frequency wires were gold coated etc. This video suggest that even DC power goes through the fields and not the wire.
MikeStroud said:
Well here's my stupid question having watched the first video:
If the power is going around the wire in the fields then why does a fuse wire blow? Surely the power is just in the field around it?
I was taught that DC and LF power went through the wire itself but as frequency increased it tended to go through the skin of the wire (skin effect) hence why some good quality high frequency wires were gold coated etc. This video suggest that even DC power goes through the fields and not the wire.
I cannot recommend enough the above linked Alphaphoenix video on the subject. Tiny amounts of power are in the omnidirectional fields. Shoving more electrons down a wire than it can handle is something else, although electrickery is still mostly a mystery to me.If the power is going around the wire in the fields then why does a fuse wire blow? Surely the power is just in the field around it?
I was taught that DC and LF power went through the wire itself but as frequency increased it tended to go through the skin of the wire (skin effect) hence why some good quality high frequency wires were gold coated etc. This video suggest that even DC power goes through the fields and not the wire.
speedy_thrills said:
The Poynting vector describes the flow of energy through a static EM field but the description in the video is not correct because the question is about a dynamic system (you are flipping the switch.) This is an electrodynamics problem and that means you need an equation that includes a "t" for time and, as you may have noticed, the pointing vector does not have a time variable.
Someone sent me this video today and it's a far better visual demonstration of what actually happens when you flip the switch on a circuit:https://youtu.be/2AXv49dDQJw?si=nxD0aQEJimEvgl7Q
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