Note durations and rhythmMusical Discovery has an individual screen for each note and rest value, with audible and graphic demonstrations alongside the text.
Durations (lengths) of notes
The duration of a note indicates the amount of time it should be sustained. It is sometimes called note value or note length. In musical notation it is indicated by the shape of the symbol written onto the staff. For example, the note symbol may be black or white (i.e. hollow), and it may have a stem and flags. The hierarchy diagram on the left shows the relative lengths of notes, starting from a semibreve at the top.
There is a significant difference between the British/Australian
terminology, and United States of America terminology used to describe
note values. The most common note value is the crotchet (British) or
quarter-note (USA). It is represented in musical notation by a black
circle with a stem. This is used to indicate tempo in metronome settings,
such as 80 crotchets per minute, written as 
=80.
The actual duration of a note in seconds depends on the symbol and
on the tempo indication. If the metronome is set to 60MM, or
=60,
which means 60 crotchets or quarter notes per minute, then each crotchet
or quarter note will last exactly one second. This is a very slow tempo,
often marked as largo. A moderate speed, such as andante,
would be =120,
which means each crotchet or quarter note will play for half a second.
The table below illustrates the notation used for some of the most common note values.
| Symbol | Australian & British | USA | Time value in crotchets or quarter notes | Description |
|---|---|---|---|---|
 |
Semibreve | Whole note | 4 | This is the longest note in current use. |
 |
Minim | Half Note | 2 | Half the length of a semibreve. |
|
Crotchet | Quarter Note | 1 | This is the length used most often, and the standard for specifying metronome settings. |
 |
Quaver, and two quavers beamed | Eighth Note | 1/2 | There are 8 to a semibreve. A single quaver has a tail on the right of the stem. Quavers are usually grouped together in pairs, sometimes in fours, with a beam instead of tails. |
 |
Semi-quavers, a group of 4, beamed together. | Sixteenth note | 1/4 | There are 16 to a semibreve, 4 to a crotchet. A single semi-quaver has two tails on the right of the stem. Semi-quavers are usually grouped together in pairs or fours, with a double beam instead of double tails. |