The study of waves therefore forms a topic of central importance in all physical science and engineering. 1  The simplest types of wave motion are vibrations of elastic media, such as air, crystalline solids, or stretched strings. If, for example, the surface of a metal block is struck a sharp blow, the deformation of the surface material compresses the metal in the vicinity of the surface, and this transmits the disturbance to the layers beneath.
There are many aromatherapy recipes for treating the symptoms of respiratory infections. Here are a few: For blocked sinuses and tight dry coughs add two drops of eucalyptus radiata essential oil to a bowl of hot water. Drape a towel over the head and lean over the bowl.
Most of the time, irregular coughing is caused by a respiratory tract infection but can also be triggered by choking, smoking, air pollution, asthma, gastroesophageal reflux disease, post-nasal drip, chronic bronchitis, lung tumors, heart failure and medications such as ACE inhibitors.