eli5 – If a balloon is rubber, and rubber is an insulator then how come rubbing a balloon on your head creates electricity?
In: Earth Science
Because rubber is an insulator.
If you rub a piece of metal on your head (gently of course) any charge it contacts flows through the metal and into your hand. No electricity remains in your hair.
Rubbing your hairs against each other produces static electricity, this is also how clouds make lightning. Since the rubber is an insulator, the charge can’t stay there, and it has to go back into your hair.
Electrostatic charge and electricity are two different things, in fact you wouldn’t be able to do that if the baloon was conductive.
When you rub a balloon with the appropriate material like your hair as you mentioned, you cause some of the electrons of one of the objects to stick to the other causes the baloon to have an electrical charge. because of the excess or lack of some electrons, if the baloon was conductive, the electrons wouldn’t be stuck and if there was an excess it would find its way out before you stop rubbing it.
Electricity is a continuous flow of electron through caused by a voltage, electrostatic charges are just an excess of charges.
I don’t think the wording of “creating electricity” is particularly helpful, so I’ll try and explain it differently.
So, conductors, the opposite of insulators, are usually used as a medium for the flow of electrons. The flow of electrons is essentially what electricity is; it’s moving electrons. Conductors, like metals, allow for electrons to flow pretty freely, because their atoms don’t latch onto the electrons as much.
As for insulators, electrons can’t flow so easily through them; the atoms and molecules tug on the electrons pretty hard, keeping them in place nearby. Since electrons can’t flow, electricity can’t happen through an insulator as easily.
Thing is, if you really wanted to, you could force an electron onto an insulator or forcibly take them off. When you rub on the balloon against your hair, you’re essentially scrubbing the electrons on/off with friction.
Now, the electrons might not be flowing, but they can still get deposited forcibly onto other things. Important though, they’re not moving. This is part of why static electricity is called static electricity. (what they call the electric phenomenon you experience when you do the balloon and hair thing).
The electrons are static; they aren’t moving. But, even though they aren’t moving, some things about electrons still apply. Like, negatively charged things (things with more electrons relatively) and positively charged things (things with less electrons relatively) attract.
When you rub the electrons on or off the balloon, you’re giving the balloon a negative or positive charge, that likely will be opposite to what you just rubbed the electrons off of/on to. So, they’ll attract each other.
Sometimes, the charged things will attract each other so much that the electrons can start moving on their own, across the grabby insulator and through the air, which zaps all the electrons back quickly until the charges on the objects are about neutral (the same amount of electrons relatively). That’s the static shock you get.
That was a bit wordy, but I hope I explained it well.
An insulator is a material that electrons have a hard time moving through. The “electricity” on the balloon is called static electricity, or static charge. What’s going on when you rub the balloon is the balloon is either gaining or losing electrons. Whether it gains or loses electrons depends on what material you’re rubbing in against.
Let’s say it gains electrons. Because electrons have a hard time moving around through rubber, those electrons stay in the area where you were rubbing. That build up of electrons is the static charge.
If you were to dump a bunch of electrons onto a conductor like metal, the electrons would repel each other and easily move away from each other through the metal dispersing the charge.
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