Where is wi-fi on the electromagnetic spectrum?
I picked up that it is microwave and radio wave. It is both because the ranges of microwave and radio overlap. But I want to nail that down.
(Is that pink on the visible light spectrum?)
Does Wi-Fi use microwaves or radio waves?
Quora
bonus:
Why is wifi perfectly safe and why is microwave radiation capable of heating food?
I gave an amateur science lesson a couple of years ago, about electricity and magnetism. But that left me with a couple of unanswered questions.
We made an electromagnet with a circuit of wire and a battery. So two questions:
1. Isn't that a short circuit?
The answer is a bit of a mess, at least to me. It is a shortish circuit. But there are factors including (don't quote me on this) the length of wire, thickness of wire, material, insulation, and it could always
be turned off.
There's also "Why is a Coil not a Short Circuit? All this and more with a Little Theory and a lot of Practice". This is longer, but probably more instructive, also practical. It goes into coils.
You can go down the rabbit trail of inductors, the coiled wire. Electricity automatically causes magnetism. Magnets move electrons, which are (electrically) charged particles. But the flow of electricity changes over time for
some reason. I don't know how that prevents a short circuit. I guess inductors are used for alternating current, not direct current.
2. If you wrapped the cord from your vacuum cleaner around a metal rod, wouldn't that be an electromagnet?
NEW No, it doesnt work because current is going both ways in the two cords, and the magnetic fields cancel each other out. Someone tried it
here.
Gas stoves are ignited using the piezoelectric effect. What about lighters?
The piezoelectric effect is when you hit a crystal you get electricity. When you hear "click click" when turning on your gas stove, that is a little hammer hitting a crystal to make a spark. Some gas stoves are ignited using the piezoelectricity. I'm not sure which ones (a minority? old?), and this bugs me because my friend has a gas stove. A stove that uses piezoelectricity would have no need for a power
cord. Camper stoves use piezoelectricity.
Your classic cigarette lighter uses friction with ferrocerium against steel, while some cigarette lighters use the piezoelectric effect. The bigger lighters used with barbecues are
definitely piezoelectric.
How Lighter Works- (ZIPPO, BIC, Piezoelectric)
I don't know what that "opposite polarisation states" business is about, but we'll dip more into piezoelectricity later.