system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is it possible for tiny SD cards to have 200GB storage? How do they create more storage space on something that small?

Basically I don't understand how a tiny thing like that can hold 200gb of data. How do they make them so they can hold so much information?
gpt
Imagine you have a lot of glasses on your kitchen table in a grid.  You also have a garden hose.  For each glass you have two choices, either fill the glass full with water or leave it empty. It is up to you. 

This is a basic memory cell.  With this setup you can store a combination of 1s (glass is full) and 0s (glass is empty).

You can probably only fit 500 glasses on your kitchen table, so your memory capacity is limited by the size of your table assuming you only have normal household glasses.  In computer jargon, we would say you have 500 'bits' of memory. What can you do to increase the amount of memory you have? 

The first thing is to get some smaller glasses.  Shot glasses would do just fine.  You can probably fit 4 shot glasses in the footprint of your kitchen glass.  Replacing them all with the shot glasses will give you 2000 'bits'.

The other thing you could do is change how you represent your information.  Instead of only filling up the shot glasses full or leaving them empty, you could use the water level as a way of representing more data.  You could say, empty is 00, less than half empty is a 01, more than half empty is a 10 and full is a 11. See, now we are using one glass to store the same information as two glasses used to. 

This is essentially what has been happening with the flash technology that is being used to make these memory cells, a combination of shrinking the bit storage units and changing the way that the information is represented.