Universality vs means testing

From interfluidity

Berkeley Fire studies

https://firelab.berkeley.edu/resources/an-introduction-to-fire-protection-engineering-and-research/

Great video linked to Feynman explaining what fire is 

Guitar: from zero to decent

 I’ve been playing guitar for several years now.  I’m able to play quite a few songs through extremely well & sound pretty good sometimes.  I don’t have great technique yet (and might never) but am growing.  My mathematical ability helps me get music theory and I’m starting to compose.  I’ve played a little bit with other musicians in (a) a band setting (b) a guitar circle (at Pablo’s) and (c) with Ken and occasionally Dennis & others as 2 guitars.  I’d like to play more with others but it’s now pretty challenging in COVID times.

I’m going to babble a bit about the learning path as I think I’ve become somewhat enlightened.  I suspect a lot of readers will find what I say completely obvious or completely opaque, but I will try to hit the happy medium of insight and information and clarity.

Going from zero to something

One can learn to "play" by learning how to put fingers of the left hand onto various strings at various places (in between the frets), and then using the right hand to make some strings vibrate, either by strumming (dragging fingers or a pick along all or some of the strings) or plucking individually somehow. This doesn't teach much about music or guitar, but it's pretty cool that in just a few minutes with a guitar one can actually make sounds that are recognizeable as music.  Can probably do a passable "Twist N Shout" in a couple of days.

Usually there are two directions to follow

1.  playing individual notes of a melody and 
2. playing multiple notes of some "chord".  As we learn more, we find that they are related...

Aside: time

Music is clocked.  There is a tempo.  There is usually a time signature, like 4/4.   Music comes in "bars" which are the duration of what the time signature reveals, e.g. 4/4 says that a bar (or "measure") contains 4 (the upper number) notes,  each is a 1/4 note (the bottom number).  So, 3/4 (waltz time) has 3 quarter notes per bar.

There are usually song sections that are an even number of bars, often a power of 2.  The "middle eight" is a common name for a bridge section which might be eight bars.

Before we go too far along this line yet, the key idea of the clock is that everything happens in time, and regularly in time.  Playing together, you all have to be on the same clock.  Drummer drives the bus, bass player and rhythm section follow along, and melody instruments / singer match up.  Now, really, the rhythm accompanies the singer, and the singer should be driving, so we all need to react appropriately as the song goes along.

Key idea distilled: always practice to a beat.  Use a metronome.  Does not matter if it's really really slow.  It's best to practice / play slow and correctly, then speed up a little, as long as you remain correct.

Melody

The melody (or "head" in jazz parlance) is the essence of the song.   With a melody you can embellish with

• percussion, to keep time (and maybe add some rhythmic interest)
• A bass line, more or less playing the lowest note that harmonizes (what he say?)
• harmony.  Basically some other notes that work well with the melody note
• and you can have multiple instruments harmonizing to fill out the sound

Chords and strumming

 It's often the case that the guitar is harmonizing the vocals.  We can play chords and sing the melody.  There are not very many real chords (although technically, I know thousands of "chords" that have their own unique name, or perhaps multiple names depending on the situation the chords is used in, basically there are two main flavors, major or minor chords, and a couple of extra flavors of major)

If we have a single note, we can call that the "root" of the chord.   We build chords from the root and two or more of the other 11 notes that are in the western chromatic scale.  These are not quite universal but pretty much - there is some psycho-acoustics that can get us musical notes from first principles).  

We can call one of the 12 notes the "key" of the song, and that imples a smaller set of notes that can be used, we will call a scale.  There are some useful 7 note scales, and 5 note scales.  There are hundreds of other scales, most of which are rarely used primarily because they sound crappy unless you have deep mastery.

Here it be good to learn "intervals" and shit but it's hard work to get it all down.  If you do, it turns out chords are pretty easy.    If we start with the root note, the note that vibrates at 1.5 X the frequency is the "fifth".  It's called the fifth mostly because it's the fifth note in the standard major scale.   It harmonizes well with the root note.  Pretty bland with just these two although used a lot in rock music.  In between there are two notes that are really useful, called the minor third and the major third.  If you add one of these to the root and fifth you get either a minor chord or a major chord.  The third gives the chord a lot of "flavor".

On the guitar, almost all notes can be found in more than one location.  Any choice of root, third, fifth will sound like the chord, although these different "voicings" will have subtle differences in quality.

[going to post for now but this is less than 10% complete...]