What is this scroll experienced called?

How would you describe this scrolling experience (beyond parallax—this term has become to vague for clients who all seem to assign their own definition to it)? And how is it achieved?

Specially, I'm referring to the contents upward momentum that's a bit delayed after you scroll?

Example 1 Example 2

Thanks for any input!

Epic visual tool

Epson 5030UB 2D/3D 1080p 3LCD Projector Submitted February 01, 2016 at 12:26AM by wmanderson http://ift.tt/1QRoZBk