The scale in musical theory describes a series of ascending or descending notes, each of which is a tone or semitone apart from its neighbour. At least, that is so for most music. Sometimes you may encounter scales with intervals of less than a semitone: Indian sitar music is a prime example. The American jazz vibraphonist Emil Richards experimented with such scales in his 'Microtonal Blues Band' in the 1970s.
There are a number of different types of scales used commonly in music including:
Names of degrees of a scale
Degrees of the scale are often named:
1 2 3 4 5 6 7 Tonic, Supertonic, Mediant, Subdominant, Dominant, Submediant, Leading note
They can also be named according to the more vocal:
1 2 3 4 5 6 7 8 Doh, Rah, Me, Fah, Soh, Lah, Te, Doh
The simplest system, however, is naming each degree after its numerical position in the scale (eg the 1st, the 4th.) Note because intervals are inclusive, a 5th describes a note which is four notes after the tonic.
Fish scales are bony and covered with a smooth transparent tegument to improve the flow of water over them. Reptile scales are more like fingernail. Birds also have scales, commonly on their feet, and their feathers are thought to have been derived from modified scales. A few mammals also have scales, such as the pangolin, and these are originally derived from hair.