Specifically in terms of what works at grade school levels:

Teachers without music background often think that playing records on a list of "good music" is "music education."

For gradeschool students, I disagree.

Some school systems think that getting every student a pseudo-instrument and forcing them to make noises is "music education."

I disagree.

In my grade school, the teacher who happened to actually know something about music visited third through fifth grade classes, or brought them to the nearest classroom where there was a piano, and played simple songs while each student had a copy of at least the melody line in standard notation in front of them. We played the instrument every student already had, i.e. we sang, to the teacher's piano accompaniment. "Music class" was about one hour per week, usually, IIRC.

I could read simple music before I finished third grade, although probably fewer than half the class had acquired significant ability.

Before I got started at fourth grade I bought myself a 50-cent harmonica and learned to play familiar tunes "by ear," in part because the "first lessons" were presented as, and demonstrated to be, "something we just do."

By the time most students got to fifth grade (the one where the "music" teacher taught all subjects) nearly all students could sight-read tunes and half or more of them could read and sing simple harmony parts - on sight, and with no real rehearsal.

I don't recall that the sixth grade had formal "music" classes during the year I was there, although in some years they did. By sixth grade, "volunteers" from the sixth grade could opt to participate in a "chorus" for occasional "public performances," and some lower grade students were "optionally included" if they were prepared and willing.

Thank you, Miss Briggs.

It would appear that a majority of students from my grade school continued with choir, chorus, band, or orchestra in Intermediate School (seventh thru ninth grades then). Percentages for other schools were variable, but generally very much lower.

My dad handed me a saxophone and informed me "you're a sax player now" a couple of weeks before before school started when I was beginning Jr. Hi.. Since I had "no music training" they put me in the "Beginners Band." Three weeks later they forced me to move to the Advanced Band (there were only those two), thus permitting me to evade ever being "taught anything."

Thanks again Miss Briggs.

John