I know that obviously a tablet has a higher screen resolution than a phone because it has more pixels(dots on the screen) From what ive been reading, tablets also have a higher dpi(dots per inch) than phones as well. How can you tell that one screen has a higher dots per inch than another screen? If i launch angry birds on both screens, they look pretty much identical. I know for resolution - bigger screen - more dots
2 causes why DPI differs. You must be aware of both the causes.
1) Physically more dots per inch: Better technology of the screen.
Example: Screen is 2" wide and it has 500 dots, so per 1" it is 250 dots (=250 dpi) Another screen is 10" wide and it has also 500 dots, so per 1" it is 50 dots (=50 dpi)
2) Virtually: physically same technology of the screen (see point 1: technology of screen), but different resampling.
Remember when you set up the PC desktop resolution. You have the same screen, but you can set different resolution (view quality), so in this case you can set dots per inch up to maximum of the screen allows (see point 1: technology of screen).