Is this true?

Each school day, millions of students move in unison from classroom to classroom where they listen to 50- to 90-minute lectures. Despite there being anywhere from 20 to 300 humans in the room, there is little actual interaction. This model of education is so commonplace that we have accepted it as a given. For centuries, it has been the most economical way to “educate” a large number of students.
Why School Should Focus on Engagement Instead of Lectures by Salman Khan

I'm trying to think how long I talk at a stretch, with no word from my students.

Five minutes? (For passersby, I teach freshman composition in the context of an English class.)

I'll have to time myself.

It strikes me as unlikely in the extreme that "millions of students" are spending entire school days listening to 50- to 90-minute lectures 6 hours a day.

In fact, it strikes me as being at least somewhat unlikely you could force millions of students to listen to 50- to 90-minute lectures 6 hours a day even if you tried. But I could be wrong.

My impression (and again, I don't know) is that the only teachers using straight lecture as their predominant or exclusive method of conveying knowledge to students are college professors teaching lecture courses. And lecture courses in my experience typically have "recitation" or "discussion" sections where the content of the lecture is elaborated and questions answered.

Plus college students take four courses, or thereabouts, each of which meets typically 2 to 3 times a week, so college students aren't spending 6 hours a day listening to lecture even when they're taking 4 lecture courses.

Besides which, I object to the blanket assumption that lecture is somehow an intrinsically bad form. The lecture is a time-honored, efficient, and often inspiring means of organizing and communicating material from an expert to a novice -- or from an expert to a colleague.....

And with that, I see I've veered off-topic.

A school would play heck getting me to pay attention to 6 hours of lecture a day, that's for sure. I don't have the focus.

Good thing no school I attended ever tried it.

Back to K-12. My intended topic is not to ask: Do students listen to lecture? I'm sure they do.

My intended topic is to ask: Do students in K-12 spend 6 hours a day moving in unison from classroom to classroom where they listen to 50-to 90-minute lectures?

(And, if they do, my follow-up question is: how is that possible?)

People seem to think "explicit instruction" means lecture, which is not remotely the case.

See, e.g.:
Barak Rosenshine, Five Meanings of Direct Instruction and Principles of Instruction; and Doug Lemov, Teach Like a Champion.

Not only does "explicit instruction" not mean "lecture," it means almost the opposite. I recall watching a professional development video on direct instruction a few years back (no longer available online, it appears) in which the presenter gave teachers an explicit figure for the number of questions they were advised to ask per each 20 minute segment of class time.

It was a lot.

[pause]

OK, here we go. The Use of Questions in Teaching, 1970:

Certainly teachers ask many questions during an average school day. A half-century ago, Stevens (1912) estimated that four-fifths of school time was occupied with question-and-answer recitations. Stevens found that a sample of high-school teachers asked a mean number of 395 questions per day. High frequencies of question use by teachers were also found in recent investigations: 10 primary-grade teachers asked an average of 348 questions each during a school day (Floyd, 1960); 12 elementary-school teachers asked an average of 180 questions each in a science lesson (Moyer, 1965); and 14 fifth-grade teachers asked an average of 64 questions each in a 30-minute social studies lesson (Schreiber, 1967). Furthermore, students are exposed to many questions in their textbooks and on examinations. [emphasis added] 

This is what everyone on the planet (our current planet, I mean) seems to have forgotten: old-time teaching wasn't about teachers standing on a stage delivering a lecture for 50 or 90 minutes.

How could it have been?

How would that work in a one-room schoolhouse?

Old-time teaching, as far as I can tell, was highly interactive and fundamentally social. Probably most effective teaching is fundamentally social; at least, I wouldn't be surprised to learn that it is.

And that's the problem with trying to learn math from a math video. It's lonely!

I'm pretty sure that reforms whose purpose is to topple straw men are the wrong reforms.