system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do electronic screens look like they're having a seizure whenever you take a video or a picture of them?
gpt
Because they are being refreshed a certain number of times per second.

The device you are using to record shoots a certain number of frames per second as well.

The chances of these rates aligning is very small.

Therefore, you might capture empty frames sometimes.

Also, screens are refreshed from top to bottom, or some other method. You might catch half a frame even.