ELI5: What difference does resolution make?

[unplanned bacon]

On two screens of the same size what difference will having a 2K display make as opposed to a 1080p one? What difference does it make in phones (and TVs and monitors)

 

[Dunlop0078]

The amount of pixels, if you go up close to the tv you should be able to see the tiny squares that make up the image those are pixels when you have a higher resolution tv you have more of those pixels. It makes the image look more crisp and clear. Same deal with a phone, my galaxy s6 has a very high resolution screen that you can press your face up to and not see any pixels. Its hard to describe the effect higher resolutions have besides saying things like it looks more crisp and clear, its something you have to see for yourself to appreciate.