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.
Sound is actually an energy wave of molecules that create a vibration. Sound can travel through and bend around many objects, including water. Check out how sound works: 1  When an object moves it creates a vibration. 2  Vibrations move air particles around. 3  These moving particles are constantly bumping into each other. 4  Our ears can pick up these particle-vibrations as sound. 5  Fast moving particles create a high sound, while slow ones are low-sounding.