In musical notation, a beam is a horizontal or diagonal line used to connect multiple consecutive notes (and occasionally rests) to indicate rhythmic grouping. Only eighth notes (quavers) or shorter can be beamed.
How many beats are in a beam note?
Notes on the first beat can be beamed with the second beat, notes on the second beat beamed with notes on the third beat, and notes on all three beats can be beamed.
How do you know when to beam notes?
In music for instruments the usual thing is to beam in such a way that the beat groups are clear. If two eighths are on the same beat then they are beamed together. In 2/2 time, where the beat has the value of 4 eighth notes, you'd beam 4 of them together.