Music sometimes sounds very high, or very low. To write these upper and lower notes on a staff takes up space, and Clefs compact that space. In fact, two staves may sit atop one another to hold all the sounds in a song.
A clef is the first symbol we see on a musical staff. With two staves, a treble clef begins the staff on top (higher notes), and a bass clef begins the bottom staff (lower notes). Clefs tell us how to name lines and spaces of staves.
A treble clef names the lines and spaces in order, from bottom, EFGABCDEF. Also, from bottom to top, the letters are in alphabetical order. The treble clef visually circles the 'G' line. This is why the treble clef is sometimes called the G Clef.
On a staff, a bass clef names the lines and spaces from the bottom, GABCDEFGA. Again, from bottom to top, the letters are in alphabetical order. The bass clef visually circles the 'F' line, and its two dots are on either side of that line. This is why the bass clef is called the F Clef. Also, the note order drops down one line or space, respectively, from the treble clef staff's notes.
Instruments that play higher notes may play only in treble clef. Those that play lower notes may play solely in bass clef. A pianist usually plays the right hand in treble clef, and left hand in bass.
As the bass clef notes get higher, they intersect the treble staff at the 'C' note. To display 'C', we must add a short line between the bass and treble staves. This is called a ledger line.
This one ledger line above the bass, and below the treble clef staves is 'C'. It's Middle C, to be exact, as it's in the middle of the two staves (it's also the 'C' key in the middle of a piano). Connect the letters from the bass clef to the treble clef, starting from bottom:
Notice the notes are in alphabetical order, starting from the bottom 'G'.
|Ledger Line||B - C - D|
To recap, Clefs begin a staff to name lines and spaces' notes. Treble and Bass Clefs have different names for the lines and spaces. These highs and lows are the sounds that sheet music transcribes. Treble is higher than bass. And the two staves share Middle C.