Massachusetts Institute of Technology
Sign in

MIT Physics Demo -- Exploding Wire

A 100 uF oil-filled capacitor is charged to 3 KV. This takes approximately 15 minutes, creating a charge on the capacitor that could be lethal. The capacitor is then discharged through a 12" length of 30 gauge bare iron wire.

When the high voltage current flows though high resistance wire, the bonds between iron molecules are shattered, resulting in a loud bang, a shower of sparks, and a cascade of wispy filaments floating through the air.

Not all of the charge on the capacitor is disharged through the wire, so a shorting bar must be used to release the remaining charge.

Comments (5)

" …creating a charge on the capacitor that could be lethal"




Posted over 9 years by Anonymous User

hey iam the first person to comment!

Posted over 9 years by Anonymous User

Actually, here is what happens in this experiment:
were you able to measure the instantaneous amperage at the moment the pulse is permitted to flow from the capacitor bank through the wire… you would find that there is much more current flowing through the wire than would seem possible. How does this happen? The disruptive discharge of the capacitor causes a huge inflow of power from the virtual vacuum into the wire… this massive inflow of power is too much for the wire to bear. it’s not just because the wire is so thin…. think about it… in the early days of the AC electrical system in the USA, electrical engineers were afraid to throw the power switch… because a huge amount of voltage and amperage could jump out from the switch and kill the operator. Where does that huge amount of power come from, they used to wonder? At first, it was believed it was a ‘backup’ in the electrical flow from the source, but when measured, it is found that the source is not capable of generating such huge voltages or amounts of current that were being exhibited when electricians were getting killed at the switch… it was Nikola Tesla who first discovered the true cause of this huge energy flow from a disruptive discharge… the sudden spark caused by closing the gap was a disruptive discharge which triggered a sudden inflow of power from virtual particles of the energy vacuum around us at all time. Nobel winner Fenyman said it… in any cubic meter of empty space is enough energy to boil all the oceans of the world… the problem is how to tap it!
After Tesla developed his AC system, in use today, he spent the rest of his life developing a power system based on sustaining the disruptive discharge effect (his magnifying transmitter).
Dr. A. Holland

Posted over 9 years by Anonymous

Dr Holland, I’m afraid you are quite wrong. There is ample energy in the capacitor to melt and partially vaporise the wire, without resorting to quantum vacuum energy!
Taking data from Wikipedia: 30 gauge is 0.0509 mm^2 so the 12" length of wire has a mass of 0.122g. The heat of fusion is 13.8kJ/mol and so only 30J would be required to melt the whole wire; an additional 741J would be required to entirely vaporise it.
The energy in a capacitance C charged to V volt is 0.5CV^2, which is in this case 450J. Most of this energy is transferred to the wire in the initial discharge – you can see from the small spark when the capacitor is ‘safed’. So plenty to melt the wire, and then some to vaporise part of it.
I doubt if Tesla knew anything about vacuum energy. The idea did not occur to Paul Dirac until 1930, by which time Tesla was 74.

Posted over 9 years by Anonymous

Whoops, I forgot the energy required to warm the wire from, say 20C to 1538C: 83J. So a total of 113J to melt the wire, starting at room temp. Still plenty left over (337J) to vaporise half of it.

Posted over 9 years by Anonymous

You need to log in, in order to post comments.

MIT Department of Physics Technical Services Group

MIT Department of Physics Technical Services Group

Category: Science | Updated over 7 years ago

July 18, 2008 11:31
Creative Commons Attribution-NonCommercial (What is this?)
Additional Files

68068 times

More from MIT Department of Physics Technical Services Group

Ripple Tank: Single and Double Slit Diffraction and Interference

Ripple Tank: Single and Double Slit...

Added over 8 years ago | 00:03:05 | 65209 views

Breakdown of Air

Breakdown of Air

Added 8 years ago | 00:02:09 | 38480 views

Confetti and the Van de Graaff Generator

Confetti and the Van de Graaff Gene...

Added 9 years ago | 00:00:55 | 48207 views

Coupled Air Carts

Coupled Air Carts

Added almost 9 years ago | 00:07:38 | 55750 views

Balloons in Liquid Nitrogen

Balloons in Liquid Nitrogen

Added 9 years ago | 00:01:18 | 51765 views

Ripple Tank: Interference of Two Point Sources

Ripple Tank: Interference of Two Po...

Added over 8 years ago | 00:01:41 | 51618 views