[HPforGrownups] How did Moaning Myrtle Make the Water Splash?

[Kimberly]

No: HPFGUIDX 93371

 (Bobby's comment)
  Here is another trivial problem I don't understand: In COS, Moaning 
  Myrtle made a splash in her restroom when HRH were there - but how 
  did she move the water?  I mean the ghosts at Hogwarts can walk 
  through the walls and floors and cannot move anything.  When Nearly 
  Headless Nick needed to make a commotion to help Harry, he had to 
  get Peeves the Poltergeist to push over a cabinet - Nick couldn't 
  move anything.  Also in the Deathday party, the ghosts couldn't even 
  smell or taste the food when they passed through the tables, let 
  alone move them.

  So how Moaning Myrtle, a ghost, make the water move?  (Or for that 
  matter, how does she remain cozy in her favorite U-bend in the 
  pipes?  Shouldn't she just pass through the sides of the pipe when 
  she wasn't looking, as it were?)

  
  (Kimberly's comments)
  Very good question, one that I myself have questioned.    My initial thought is that perhaps she is a Poltergeist like Peeves and can indeed manipulate matter for lack of a better phrase.    We also have the comment from Hermione that Myrtle likes to throw tantrums and flood the bathroom.   (CoS, US ed. pg. 133).      If she can't manipulate matter, how could she possible cause the bathroom to flood ?        

  Anyone have any thoughts on this ? 

  Kimberly