Some science behind the scenes

Western musical notation

Our western musical notation system combines the pitch with the duration for convenience – to make it easier to read the music and shorten the amount of transcription needed.

So from the above notation we know the octave and the key – so the pitch – and the symbol used shows how long the note is held.  The example shows a quaver which is played for one eighth the duration of a whole note.
This picture shows a ‘rest’ which is in effect silence together with two quavers one with the stem up and the other with the stem down.
This picture shows a demiquaver rest and also a semiquaver/ demiquaver) -  a note played for one sixteenth the duration of a whole note. The semiquaver is thus half the duration of a quaver.

Without showing the notation, similar notational rules apply to smaller divisions such as thirty-second notes (demisemiquavers) and sixty-fourth notes (hemidemisemiquavers).

A crotchet is a note played for one quarter of the duration of a whole note (or semibreve). Quarter notes are notated with a filled-in oval note head and a straight, flagless stem.  The crotchet rest is also shown.

 

This picture shows a minim - a note played for half the duration of a whole note (or semibreve) and twice the duration of a quarter note (or crotchet). In time signatures with a denominator of 4, such as 4/4 or 3/4 time, the half note is two beats long.  The picture shows a half note with stem facing up, a half note with stem facing down, and a half rest.

 

A semibreve is a note represented by a hollow oval note head, like a half note (or minim), and no note stem. Its length is equal to four beats in 4/4 time. A whole note lasts half as long as a double whole note (or breve).

The whole rest (or semibreve rest), denotes a silence for the same duration. Whole rests are drawn as filled-in rectangles hanging under the second line from the top of a musical staff.

 

A breve is a note lasting twice as long as a whole note (or semibreve). It is represented by a hollow oval note head, like a whole note, with one or two vertical lines on either side. In older notation, it is represented by an oblong shape. An alternative notation consists of two adjacent hollow oval note heads.

 

A longa, also known as a "Brasieroule Quatrinote" or a "quadruple whole note," is a musical note twice as long as a breve, four times as long as a semibreve/whole note, that appears in early music. It is equal to sixteen quarter notes, or four measures in common time. It is no longer used in modern music notation, although the sign for the equivalent rest is sometimes used to mark multi-measure rests.

As can be seen, from the above, quite complex musical compositions can thus be constructed by having a constant beat and combining pitches of various duration coupled with silences of various