Intervals, what do those numbers mean?

A Major scale is built as follow:

1 2 3 4 5 6 7

But what do those numbers mean? We mentioned they're scale degrees, but WTF?

Well, they actually mean multiple things, one of them is the intervallic makeup of the Major scale.

An interval is the space between two notes and every interval has a special name, there are many “kinds” of intervals, for now the intervals belonging to a Major scale as follows:

Scale degrees Interval Names
1 Perfect Unison
2 Major Second
3 Major Third
4 Perfect Fourth
5 Perfect Fifth
6 Major Sixth
7 Major Seventh

For now it does seem very random and disorganized how some intervals have the pre-fix perfect and some don't. But this will slowly start to become less strange the more we familiarize ourselves with the Major scale and the minor scale.

For now we can focus on the interval name itself without looking at the pre-fix. This is actually what musicians do in practice, when a guitarists says “go up a third” he actually means going up by a Major third. Same goes for all intervals, unless stated differently all intervals refer to the names labeled on the chart above.

For example if someone says “go down a fifth” they mean a Perfect fifth, but if someone is explicitly saying “raise it by a minor third” then they definitely do not mean a Major third, mud a minor 3rd instead.

The intervals from the Major scale are “the default”, in practice.

An easy way to remember the fancy names for the intervals is that only the unison, fourth and fifth are Perfect on a Major scale, and every other interval is a Major interval (aka Major 3rd, Major 6th, etc.)

There are many more kinds of intervals other than Major and Perfect, but to better understand them we need to learn the minor scale, that's coming up next!