Hi, I am currently working through my Grade 4 workbook and have come across a note which has a stem which goes down on the left and up on the right.

Can anyone explain why this is and what it means please?

most likely a unison - two notes at the same pitch. it's often seen on SATB scores where you have multiple voices in the same staff.

I haven't seen it, but it sounds to me like river is along the right lines.

I think you'll find that there are two parts written on the same staff (e.g. soprano and alto on the same treble cleff staff, or flute 1 and flute 2, or whatever). The one part (e.g. soprano) will always have all of the tails going up and the other part (e.g. alto) will always have all of the tails going down. In general the part which has the tails going up will be the higher part, but sometimes they do cross over and you'll see the odd note where the higher note has the tail going down (and is therefore sung/played by the lower part e.g. alto even though it is the 'higher' note) and the lower note has the tail going up (and is therefore sung/played by the higher part e.g. soprano even though it is the lower note). Sometimes both parts will have the same note without actually having a unision passage (i.e. it's just a small number of notes that are the same) in which case the lines go both way.

If there's more than a few notes in unision then it would normally be written like it would for a single part with the instruction S+A or Fl1+Fl2 written at the start of the passage to indicate that both parts play the same thing in the passage. So your note with tails going both ways is likely to refer to a unison note. However, this isn't the same as a unison passage or verse, which tends to get referred to as 'unison' rather than 'a unison passage' or 'unison verse'.

Thank you

i forgot to mention, this notation is also used in music for strings, where it's often accompanied by a fingering mark, and indicates that the same note should be played on two different strings. for example, an E written like this for violin might be labelled "4 0" and means you should play both the open E string, and the 4th finger E on the A string.

If you're playing a solo instrument, the direction of the stem doen't really make any difference. As river said, it's usually used on vocal scores where two singers are at the same pitch.

But it is also helpful in contrapuntal music (e.g. Bach Fugues) to show that two separate contrapuntal lines have momentarily met at the same pitch. Having two stems gives each line visual continuity and makes it easier to read. Besides, if the second stem were not there then, for clarity, the composer would have to write in a rest to show that one of the voices has stopped.

Related to this, if you study piano scores you will find that very often the same note is shown in both the bass and treble clefs - poerhaps as part of the harmonic accompaniment for the LH, and part of a melody in the right. It is just the same - the note has two functions, but on a keyboard you can onl;y play one of it.

The point is that the music is not a set of instructions for physical actions to be performed to make sounds. It is a visual representation of musical ideas. One of those ideas is the melodic line, or multiple melodic lines going on at the same time. If you could not use the double stem you'd have to write the music in an expanded form over more staves.