"The trumpet, French horn, and tuba have values with keys at the top of the valves. When the player presses a value it opens or closes some of the tubing. This is the secret. When the tubing is open, the air that the player blows into the instrument has farther to travel - the instrument is longer. When the tubing is closed, the air that goes into the mouthpiece doesn't have as far to go - the instrument is shorter."

"So, Little Violin, when the a brass instrument uses more tubing - when the instrument is longer - are the pitches higher or lower?" questioned the piano.

"I know the answer. I really do!" said the violin. "When an instrument is longer or bigger, the pitches are lower."

"Yes, you are quite right," said the piano. "Now, the trombone doesn't have values. Can you guess how the tubing on the trombone is made longer?"