How should I make this script work? I am not sure what I'm doing wrong with the Velocity part.

I have been struggling to make a script to play a sound in a BasePart when it goes a certain velocity. I am not a scripter, so this is obvious.

while true do
    if script.Parent.Velocity > 130
  script.Parent.Sound:Play()
  else
  script.Parent.Sound:Stop()
  end
 end