Half note
A half note (in British terms a minim) has a hollow head and a stem and lasts two beats — as long as two quarter notes.
You play a half note once and hold it for two beats: press on “one” and hold through “two”. Two half notes fill a measure of 4/4; in 3/4 a half note and a quarter note together make three beats.
The only difference from a quarter note is the head: a quarter note’s head is filled in, a half note’s is hollow. Hollow heads last longer. The whole note is hollow too, but has no stem and lasts four beats: one whole note equals two half notes.
The half rest is two beats of silence; it sits on the middle line of the staff. A dotted half note lasts three beats and often fills a whole measure of 3/4.
What it sounds like
A half note sounds calm and long: one sound, with two beats under it. In melodies, phrases often end on a half note.
Where it is taught: the studio’s interactive textbook, chapter 2, “Counting: the beat, quarter and half notes”.