system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does the touch screen on a phone work?
gpt
There are multiple different kinds of touch screens.

Phones generally use capacitive touch screens. The surface of the screen is coated in a transparent conductor, which is generally something like indium tin oxide.

The human body is a pretty good conductor itself, so when you touch the conductive surface of the touchscreen, it changes the electrostatic properties of the screen, and sensors attached to the conductive layer can detect where you're touching, then software maps the point you touch to what the screen is displaying and determines what function to take.

This is also why capacitive touchscreens don't work through most gloves - as gloves are an insulator and prevent the electrostatic interference. That's why some gloves have special pads on the fingertips which are conductors and allow phone use while wearing them.

Other types of touchscreens include resistive touch screens, which are more expensive [EDIT: Resistive are cheaper, but less responsive. Whoops!] but are less likely to be damaged by an environment that involves the potential for spills. These touchscreens work by pressure; there are two layers of material separated by a space, when pressure is applied they distort and touch together at the point of pressure, which can then be mapped by sensors.