Note-for-Note - Transposing from 2nd Position to 1st Position

Here's a great way to hear that the notes are the same from position to position (and to check if you're doing it correctly). Play the following Rhumba rhythm over the 12 Bar Blues Progression:

C Harmonica in 2nd Position (Key of G)
I = G B D = 2 3 4
IV = C E G = 1+ 2+ 3+
V = D F# A = 1 2' 3"

Now grab your G Harmonica and play the same notes in 1st Position:
I = G B D = 4+ 5+ 6+
IV = C E G = 2" 3" 4+ (5 6 7+ an octave above is easier to play)
V = D F# A = 2 3 4 (or 6+ 7 8 if you want to stay in the upper octave)

This is a great way to see that "this is that" and is the common way new players get a foothold in what it feels like to play in a new position. This is also a great way for experienced players to challenge themselves to play the same melody in various positions (like playing "Juke" in all three positions in Mark Hummel's Mountain Top Productions video). Try taking a melody that's in 1st Position on your G Harmonica and moving it note-for-note to 2nd Position on your C Harmonica. Try the same in reverse, from 2nd to 1st. You may have to move a portion of the melody up or down to make it work (even in the middle of a phrase), but this experimentation is what makes a player great in various positions.