Scales are notes lined up from a low pitch and going up to a higher pitch, usually in 8 (major) steps or 12 (chromatic) steps. You can also go down a scale. (In kindergarten, we teach the major scale, which has 8 notes.) Solfa is a musical language that uses hand signs to show musical notes, similar to American Sign Language (ASL). It is used throughout the world in music. The major Solfa scale is: do, re, mi, fa, sol, la, ti, do.
Intervals are when you skip one or more notes to get to the next note. Intervals in a major scale are half steps or whole steps, and include a second, third, fourth, fifth, sixth, seventh, and eighth (called an octave).
Chords are when you play 2 notes at the same time!
Here are links to ideas for teaching scales, intervals, and chords: