One of the most important observances of this
holiday is hearing the shofar in synagogue. The
shofar is a ram's horn which is blown somewhat
like a trumpet. A total of 100 notes are sounded
each day. There are four different types of shofar
notes: tekiah (3-second sustained note), shevarim (three 1-second notes
rising in tone), teruah (series of short, staccato notes extending over a
period of about 3 seconds), and tekiah gedolah (the final blast in a set
which lasts as long as the shofar blower can blow). Some believe that the
shofar's sound is a call to repentance. The shofar is not blown if the holiday
falls on a Sabbath.