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 in water and sound in air are both waves that move similarly and can be characterized the same way. Sound waves can travel through any substance, including gases (such as air), liquids (such as water), and solids (such as the seafloor).