In this lesson we will deal with seconds and thirds and the two most common qualities of each: major and minor.
Minor seconds are a half-step apart and when played together they have a distinct, highly dissonant sound. You can get a feel for what each interval sounds like by playing it yourself on an instrument; play a note and then move up or down a half-step and back. If your instrument can play multiple pitches simultaneously, play them together to hear the dissonance created.
Major seconds are a whole-step apart (two half-steps) and are less dissonant than minor seconds. If you play a major or minor scale upwards, this is the first interval you hear. Again, take your instrument of choice, and play several different major seconds to get a feel for their sound. You can also contrast them with minor seconds to hear how the minor version is much more dissonant.
Major thirds are two whole-steps apart (four half-steps) and represent the foundation of the major triad. This interval is much more consonant than either second interval and is commonly referred to as a "happy" sound (especially when compared to minor thirds and minor chords).
Minor thirds are three half-steps apart and are the core component of the minor triad. This interval is also more consonant than seconds and is the "sad" counterpart of the major third. Note that descriptors like "happy" and "sad" do not always work well because of musical context, but often it is helpful to find easy descriptions when you are first learning to help your brain recall what a particular interval sounds like.
The first six exercises cover only major and minor seconds. The first note you hear is written on the corresponding worksheet, and then it is up to you to determine the interval after hearing the second note. I recommend printing out the worksheet, listening to the mp3, and then writing down the interval under each note on the worksheet as you identify it. For major and minor seconds, intervals should be written as M2 and m2 (capital letter for major, lowercase for minor). Once you have identified all eight intervals in an exercise, go back to the worksheet and write in the actual notes on the staff along with the correct accidentals. Seconds will always be the next note letter above your root note, so your answer is more about determining the correct accidental (to be technically correct on some intervals, you must use double sharps and double flats). In later lessons, we will use enharmonic respelling to make answers more understandable (changing Gbb to F, for example), but for now it is good practice to spell intervals the correct way.
Exercises 7-12 cover major and minor thirds only. When you write the interval name, use M3 and m3. Thirds will always be two note letters above the starting note.
Exercises 13-18 use all four interval types.
The first three exercises of each group play each note separately followed by both notes together. The latter three exercises of each group only play the notes separately so you can't rely on hearing the dissonance or consonance of the dyad (two-note chord).
