system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does electric toothbrush charging work even when there is water near the end where the brush connects to the charger?
gpt
If you are talking about a wireless charger, it's just a matter of how close the toothbrush and the charger are. 

The principle is:

You have one coil in the toothbrush and one in the charger. In the one in the charger current flows in, and generate a "field of electricity" that makes the current flow in the other coil and thus recharge your toothbrush. 

Think about it like moving a magnet using another magnet close by. It doesn't matter if you have paper, water, air or anything else between the two, if they are close enough they will move.  

(This doesn't apply if you have something capable of stopping a magnetic or electric field)