eli5: how/why does water on a touchscreen have the same effect on it as a finger

Question

eli5: how/why does water on a touchscreen have the same effect on it as a finger

In: 8

Answer 1

Most modern touchscreens work by measuring capacitance. That is, the ability to store an electrical charge. When your finger touches the screen it changes the capacitance of the screen at the point that your skin makes contact. Water will also change the capacitance. So, the screen has a hard time differentiating between the two.