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.
The hotter an object gets, the more photons it gives out. Light travels as a wave. But unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuumâa completely airless space.(Sound, on the other hand, must travel through a solid, a liquid, or a gas.) Nothing travels faster than light energy.ut unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuumâa completely airless space. (Sound, on the other hand, must travel through a solid, a liquid, or a gas.) Nothing travels faster than light energy.