system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does flash memory work?
gpt
The actual science is pretty complex, but the concept is easy to understand. 

Data is stored on a PC as a series of 1's and 0's. Lots of 1's and 0's,  literally billions on a common flash drive. 1 gigabyte is about 8 billion bits (a bit is a 1 or 0).

1's and 0's are stored on the flash drive by opening or closing "gates". A signal can be used to open or close the gate to "write" the data onto the drive. When reading, a current is passed through, and it knows which gates are opened or closed by whether the current can get through the circuit or not. It translates these open and closed gates into 1's and 0's, and when put together, you have a complete file.

There is a gate for each bit (a 1 or 0) stored. They are very small, and there are millions to billions of them in a chip. Multiple chips are used to make higher capacity storage. Making single chips with as many gates, without defects, is hard to do. Many small ones is much easier.