Why do capacitors explode when you apply too much voltage?

[werto165]

I just want to get this clear in my mind, so why do capacitors explode when too much voltage is applied? Also why do they explode when you switch their polarity?

 

I'm going to try and answer the first one: because P=I^2*R as current is proportional to Voltage, as P = power which is work done over time thus this power is converted into thermal energy ? Because capacitors have a dielectric and some sort of fluid inside, is it that the fluid is heated and therefore occupies more volume as it starts to become gaseous?  Such that the outer shell/casing can't handle the internal pressure of the fluid and must explode? 

 

I have no idea about the second one, could some enlighten me and tell me if my explanation for capacitors exploding is correct? 

[SImoHayha]

Well most likely its due to pressure, because its contained in a self little sealed casing. So of course if something starts to boil, the liquid it increases the pressure and once it hits,  a threshold it goes boom

[Guest]

Capacitors explode when too much voltage is applied because + and - "plates" are very close to each other and then current jumps trough dielectric and shorts it inside. 

[Arc_Jester]

well to answer your second question reversing the polarity of a cap reduces the oxide layer that forms the dielectric on the aluminum of the cap which may cause a short circuit and this can cause it to burst, leak or explode.