How to make a glass heating element?

Question

Electronics

In general, I’m not familiar with physics - passing direct current (phone charger - 4.2 V, 400 mA) through the glass will it warm up? If not, could you suggest ideas for the implementation of this undertaking?

Answer 1

You can dance in a slightly different direction. After all, the point is not that glass does not conduct current at all, but that it conducts current damn badly. The specific resistance of glass accumulated on the Internet is 10 ¹¹ Ohm⋅m . Thus, a glass parallelepiped 1×1×5 cm in size (such a small stick) will have a resistance of 5⋅10 ¹³ Ohm. Obviously the number is huge. For comparison, the same copper rod has a resistance of ≈ 8.75⋅10 ⁻⁶ Ohm, which is 19 orders of magnitude less. But let's carry out the calculations further, because we are interested in the heating element.
In a conductor with a resistance of 5⋅10 ¹³ Ohm, a current of 1 ampere can be obtained at a voltage of 5⋅10 ¹³B. 50 trillion volts! But a current of 1 ampere in such a conductor will give us as much as 50 trillion watts (at direct current). This is too much, 1000 watts is enough for us, as in a household kettle. For a heater of this power, we only need about 223.6⋅10 ⁶ V.
On the one hand, 223 million volts does not look like such a fantastic number. According to Wikipedia , the voltage during a lightning strike reaches values ​​​​of the same order, or even more. On the other hand, the resistance of the air and the person standing next to the glass teapot may turn out to be less, and then the current will follow the path of least resistance. I'm afraid it will be too high a price for a cup of aromatic tea :-)