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Activity 12.2

Keep w riting the
sequence of white
keys from left to
right as follows, like:
CO DO EO FOGO AO
BO Cl D2 E2 .........
Keep writing like
this.

If you play Cl after ID
CO, you will find that L.....-_ _,_ _ ____....__ _ _.__ _ __.. ____________ ____,
Cl has a higher pitch
than CO because Cl
is exactly one octave
higher than CO. It
is the same note
but the frequencies
between the t wo
keys are different.
The ratio between
the frequencies of ~o
Cl and CO is 2:1.
The seven natural
tones from CO to Cl,which are represented by the white keys, are
within an octave. The other five accidental notes,namely Db, Eb,
F#, Ab, and Bb,represented by black keys are also within the octave.
Including these, there are a total of twelve tones in one octave.Thus,
in an octave there are a total of twelve different notes.

As mentioned above, the black keys numbered 2, 4, 7, 9, and 11 in
the picture are accidentalnotes, while the white keys numbered 1,
3, 5, 6, 8, 10 and 12 are naturalnotes. Identify them and practice on
your harmonium or keyboard.The average human vocal range is about
three octaves. Therefore, the use of the low, middle, and high octaves
is more common in singing and playing instruments. The low octave

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