When you play an Irish Whistle or any similar music instrument, you are making a given tone.
(A given tone can also be spoken of as a note, which is how I will refer to it most of the time in this website.)

Properties of a Tone

The Beginning Music Reader by McKinney ©1958 describes a given tone’s properties as
“1. duration – how long or how short it is
2. pitch – how high or how low it is
3. intensity – how loud or how soft it is
4. timbre – it’s characteristic quality”

Pitch

When playing the Irish Whistle, we first focus on pitch. Pitch is organized into mathematical formulas involving hertz. When you get an electronic tuner, you can see this organization very easily by simply adjusting the hertz up or down. The pitch we want to play to is 440 hertz. When you’ve selected the pitch, in this case 440 hertz, you’ll see that there is left, right, and center that a tone(or note) can be. When you play the tone correctly in the selected pitch, the tone(or note) will be marked in the center. Playing a tone(or note) incorrectly causes the note to stray to the left or the right of the center. Since this is math, it is either right or it is wrong. That is, the pitch of the note is either correct or incorrect. Further more, the pitch of the note is controlled by only three things
1. your environment – if it’s hot or cold the whistle responds much differently
2. your breath control – the speed of air from your mouth you are putting into the whistle at a certain consistency.
3. your posture – your posture affects the pitch of the note by the position of the neck and head and whistle to mouth to position.

I find it necessary to use a tuner to practice toward a 440 pitch. There are some people that have ‘perfect ears’, they can naturally tell the minutest of pitches from each other and apply them to their voice from a very young age. Don’t feel bad if this isn’t you; the majority of us must improve our ears with practice and application(this includes a great number of professionals). The good news with pitch is if you practice to excellent pitch in playing, theory has it that a vast group of people that also did the same thing could play with you and sound as one unit.

Intensity

The next thing we think of is the Intensity, or the loudness or softness of a note. If you practice enough with a tuner, you’ll soon discover that the Irish Whistle can’t pull intensity changes without changing pitch. A related instrument, the modern flute can make these intensity changes without changing pitch. Therefore, if you are playing the Irish Whistle, you should try to get the note correct and stop yourself from trying to make the note louder or softer once it is played with the correct pitch.

Timbre

The last property of tone that was mentioned is Timbre. Timbre is the character quality of a note. A note can sound soft, hard, full, or weak. You can affect the Timbre of your notes with your posture and breath control. The Irish Whistle does consistently have naturally weaker and naturally fuller notes. As a player, your skill determines how much the audience can actually hear of this. The more consistent your tone is the more of a magic trick it is to others who are listening to you play if they don’t hear a naturally weak note after a naturally stronger note.