The primary responsibilities of human resources are: 1  C - Compensation. 2  H - Human resource development. 3  E - Employee and labor relations. 4  S - Safety and health. 5  S - Staff.
A new technique uses sound waves to levitate objects and move them in mid-air. Credit: Dimos Poulikakos View full size image. View full size image. Hold on to your wand, Harry Potter: Science has outdone even your best Leviosa! levitation spell.
Any sound waves use a medium to travel along (on Earth the medium is Air, Water or any Solid. A Vacuum, like Space, does not contain any particles; therefore sound waves have no medium through which to travel and thus Sound will NOT Travel (or be heard).