Here is how to learn to play a Trumpet B Flat Major scale.
It probably looks like this:
It’s actually something better referred to as the “concert Bb scale for Bb Trumpet” and it’s probably what you’re looking for. This scale will work for any instrument built in Bb (like clarinet, tenor sax, baritone Treble Clef etc.) The fingerings for Trumpet appear in tiny text above. Learn now to extend the 3rd valve slide for the low D. Just put it out about a half inch or one centimeter for the D then pull it right back in. That’s a subtlety that will become increasingly important and which will help distinguish you as the one Trumpet player in your band who plays in tune.
This scale has two names. Because you play a transposing instrument it is also referred to as your C major scale. The business of being a transposing instrument simply means that when you play the most naturally occurring (open valve) notes on your trumpet ( C, G, C, E, G) they match up with the most important notes of a Bb scale on the piano, organ, flute, bass, etc etc. The clever people who wrote and printed the music you’ll read in Band class have taken that discrepancy into account and changed your notes for you. If you’re intrigued, or if you’d like a reason to think that there’s something not-quite-right about the trombone, read this page … (that post isn’t ready yet, but I’m really excited about it)
On the off chance that you got here looking for a major scale that starts on your Bb you want to go to THIS page with all 12 major scales on it.
If you are a real beginner those fingerings up there will not be enough to get your scale sounding good. You should read this page …