because i have a lot of younger students, i'd like to ask other teachers/pianists out there how they've gone about introducing scales to their students.

I start by teaching tetrachords eg CDEF using the pattern Tone-Tone-Semitone to work them out. They start on C and work each one out in the following order:
CDEF
GABC
DEF#G
ABC#D
EF#G#A
BC#D#E
They then play each tetrachord using right hand fingers 1-2-3-1, and then also with fingers 2-3-4-5.
We then do FGABb using just 1-2-3-4
and F#G#A#B using just 2-3-4-5
They can then play a one octave major scale on each white key with their right hand. The same process can be done with left hand (obviously some alteration to fingerings) and eventually we add another octave and those on black keys.
This can be done with surprisingly young children. If they learn ALL the scales quite quickly they enjoy knowing scales usualy reserved for high grade students (eg. F# major) and it avoids the problem of them finding certain keys or scales intimidating.

Chris has good advice. I don't have much in the way of teaching experience, but one thing I would do is not avoid the "advanced" scales in the beginning. That's not to say that you shouldn't start with the easier ones, but I know plenty of beginner students who were "afraid" of the more advanced ones. There's nothing conceptually harder about them - in fact I find them easier.

In teaching me scales, my teacher told me how Chopin would teach his students C major last, because he found it the hardest. While I don't know if I'd go to that extreme, I can kind of see his point - with C major you're "lost in a sea of white". Other keys have black notes interspersed which can act as "markers" to help you know where you are. For example, with E major RH ascending, you always tuck the thumb when you're moving from a black key to a white key - simple.

Even now, I find the keys with lots of black notes to be easier when it comes to scales.

For piano students, I start scales by first showing them the concept of tucking the thumb under the fingers away from the piano, using 2,3, and 4 as the crossing fingers, then introducing one-octave scales for the level they are preparing for, then move to two-octave scales (and the 1 under 4).

Meri