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, unlike mass, is a characteristic of the medium. If you can get air molecules to move together to transport momentum through the air, that motion is sound. Moving air molecules is what the speaker in your radio or phone is designed to do, and electromagnetic fields working with a magnet make the speaker move.