How do touchscreens work?

You ask: How screen feel finger?

Strange thing: glass no have skin, yet screen know just where finger land. Trick is electricity, not push. Under glass hide grid of lines so thin eye no see. Phone put tiny electric charge on grid, like still pond of lightning-juice. Caveman body full of salty water — six parts in ten of Caveman body is water — and salty water carry electricity good. Finger come close — finger sip little charge from that spot. Phone watch every crossing point on grid, notice charge drop here, so finger must be here. Grid very fine, so phone find spot exact, even track two fingers pinching. This why screen ignore stick or thick hide glove — dry stick no drink electricity. Press hard change nothing; light salty touch is everything. Cave wisdom: screen not feel push. Screen feel finger steal tiny lightning, and see where theft happen.