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.
When something vibrates (like your voice box) it causes the molecules around it to also vibrate, which then causes a ripple of motion (known as a sound wave) that can travel through air, water, and solid materials such as wood or a piece of string.