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.
SECTION 3 Light 425 Waves in Empty Space On a clear night you might see the Moon shining brightly,as in Figure 16. Like other waves, light waves can travelthrough matter, but light waves are different from waterwaves and sound waves. Light from the Moon has traveledthrough space that contains almost no matter. You can seelight from the moon, distant stars, and galaxies because light isan electromagnetic wave.