Catch the Mistake! Exploding Wire

Рет қаралды 9,759

9 жыл бұрын

As many of you pointed out, we make a mistake in this video. It's inexcusable that we did, but we finally made corrections in a new version ( • MIT Physics: Exploding... ) BUT! See if you can catch the error in this original version.
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Пікірлер: 21

@DoomedToMyBreed 9 жыл бұрын

"the thick copper bar has a way higher resistence that the thin iron wire" Isn't that the opposite? shouldn't the thickest conductor has less resistance?

@rpk5568 7 жыл бұрын

I'm sorry to have to say this but, the wire has a higher resistance than the copper bar. That resistance created heat in the wire which is why the wire got red hot. The copper bar with less resistance conducted all the remaining voltage and didn't get red at all and it did it almost instantly. She's got it completely backwards. How does this happen?

@nicholasvlamis3517 9 жыл бұрын

The thin wire had higher resistance than the flat bar! That is not the issue that led to the fireworks. The thinner wire has much less mass, and therefore the energy dissipated from discharging the capacitor transformed into thermal energy and was enough to melt the wire. Keep in mind that the bar discharged the capacitor without much excitement, but if the energy in the capacitor was much much larger, then the bar would have the same demise as the wire....

@Silvertestrun 9 жыл бұрын

Excellent, loved it.

@k7iq 6 жыл бұрын

Replace the word "resistance" with the word "conductance" and it works out much better. I think that's the "mistake" they want you to catch.

@MrMr999Mr 9 жыл бұрын

Great video. Thanks for making it.

@danielmcsween884 9 жыл бұрын

but MIT teaching wrong stuff publicly on the internet, resistance of a conductor is equal resistivity of a material * length/ cross sectional area. The thick plate would have alot less resistance and current through it would instead be higher. I demand my space in the university now

@danielmcsween884 9 жыл бұрын

the energy discharge is equal the potential difference and though the same amount of energy will be released with equal voltages the resultant heat formation from the electrical energy would heat the small mass of the thin wire much more than a bigger mass copper plate. (energy provided= mass*specific heat capacity*temperature change)| the thin wire would heat up beyond the melting point almost instantly and explode

@danielmcsween884 9 жыл бұрын

just finished exams

@fplasil 8 жыл бұрын

I agree with Daniel below. I caught the same mistake in the narration, then checked if anyone else thought the same in the comments.. The thick copper bar at the end has to have smaller resistance than the thin wire. So the current through the bar would have been larger than the current in the wire. Here is the thing though, the first experiment must have decreased the voltage difference across the capacitor, right? So there is actually no way to tell which current was larger based only on comparing the resistance of the wire and the copper bar. Do I have it right?

@varunalur2048 7 жыл бұрын

Thx ! would love to learn stuff like this at campus one day !

@Jonas_Meyer 8 жыл бұрын

I like how 4 of 10 comments on this video correcting a minor blooper.

@Lerkero 9 жыл бұрын

That was a large explosion for such a small wire. I wasn't expecting that. Who knew such a small wire would caution protective equipment.

@lucas_vasconcelos 9 жыл бұрын

nice

@samuelfey4924 9 жыл бұрын

are electrons positive too? or are they just negative?. so the positive charge are just protons right? >S

@unitelanka 9 жыл бұрын

Samuel Fey electrons are negative. a positive charge just means there's a lack of negative charge (less electrons) in the positive plate. Protons can't move through metal so they are not relevant here.

@creepyloner1979 3 жыл бұрын

@@unitelanka wrong. protons have a positive charge. removing electrons only creates a positive charge because there are still protons remaining in larger numbers than electrons and protons are relevant here because electrons and protons attract each other which is what drives current flow along with the electrons repelling each other.