There are two small dots in music that look identical and do opposite jobs. The only way to
tell them apart is where the dot sits.
A duration dot sits directly after the notehead, level with it, on the same line or
space. It lengthens the note by half again (the lesson you just read).
A staccato dot sits above or below the notehead, clear of it. It means short and
detached — a way of playing the note, nothing to do with how long it's written.
The same quarter note, three ways
72 bpm
First a plain quarter D. Then a dotted quarter — the dot is beside the head, and it's held 1½ beats. Then a staccato quarter — the dot is above the head, and it's played short and clipped, but it still counts as a full beat.
A line of duration dots
60 bpm
Every dot here is beside a head — these are all length. Long–short, long–short, then a three-beat note. Count it: the dotted notes eat into the following beat.
A line of staccato dots
80 bpm
Every dot here is above a head — these are all articulation. The count is unchanged: plain quarters and a half note. The dots only tell you the composer wants the short notes crisp and separated.
Read one that has both
66 bpm
Which dots are length, which are articulation? Work it out, then reveal. (The first is a dotted quarter; F and G carry staccato dots above.)
Read now, play later
You only need to read the difference here — spot which dot it is, and know a staccato dot
doesn't change the count. Playing a clean staccato is a bow skill, and that's Stage 5.
For now: dot beside the head → add half the value; dot above or below → count normally, and
note that the composer wants it short.
The usual mistake
Seeing any dot near a note and stretching it — so a staccato passage drags. Or seeing a
dotted quarter and clipping it short because it looked like staccato. Check the dot's
position before you do anything with it.