system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are screens flickering when you're trying to take a photo of them?
gpt
The screens are flickering all the time. 50 or 60 or more times per second, that’s how you see movement on the screen. Our eyes however can’t see this; we can see a flicker of a few times  to 10/12 times per second (and we see them as individual images in those cases) , but going beyond 24 per second, our eyes and brains can’t process them individually and we interpret that as motion. 

Cameras, like ones on your phone, can actually capture the moments between the image changes; so you see parts of different images being replaced by new ones, and parts remaining the same, so you get “streaks”