Design tricks, what are their names?

• I was wondering what is the name of the scrolling design thats used here: http://ift.tt/2gY1KJg
  and here: http://ift.tt/1dEZIKz
  I'm thinking of when you scrol a little it automatically positions a class or id in the middle of the screen and at the same time the page "blocks" you from stopping the scrolling between the slides(or divs?)

• On the NatGeo page with kennedy, what is it called when the screen "follows" the pointer?

if someone could point me in the right direction on how to use or where to learn it, that would be perfect. Thank you!