Scales are always practiced on any instrument.
  Since it is the most basic arrangement of notes, by practicing scales students will be practicing phrases that appear in many pieces in advance.
  Once students can play in one key, practice other keys as well.
  When playing in an ensemble, practice from the lowest key to the highest so as not to strain the brass.
  Woodwind instruments often use fast scales and variations of these scales in their music.
  When practicing each part, be sure to practice thoroughly using as wide a range of each instrument as possible.

  Chromatic scales are also important, but I don't think they are practiced much in elementary school.
  For brass instruments, it is effective for expanding the range because it does not require straining the mouth movement, and for woodwind instruments, this allows to practice using less commonly used keys.