What are harmonics? Simply put, harmonics are notes that are created by “overblowing” or “over-voicing” one note to produce a higher note without changing any fingerings. It is similar to how brass players change notes with their lips and air. Woodwind players that develop their harmonics will quickly see the benefits as their tone will become more clear and it will be easier to play both low and high notes.
How do I achieve harmonics initially? On flute, you will quicken your air speed, shrink your air stream, aim your air slightly more across the tone hole, and raise your tongue slightly. Remember, this is done entirely with our embouchure and air. Don't change fingerings. Try the exercises below.
Using only your air speed, size, and direction, try "over-blowing" your low C. Middle C should pop out above it.
Continue moving up chromatically until you get to C#.
Sample below.
Similar to exercise #1, but now try to get another note higher above C. It should be a G.
Continue moving up chromatically until you reach middle C#.
Sample below.
This is just an example of how far you can take harmonics exercises. Continue reaching as high as you can go, making sure to not skip any harmonics on the way up or down.