[MUSIC]That was music from George Gershwin's1930 musical Crazy Girl andthe song I've Got Rhythm.We'll we've all got rhythm.Rhythm along with melody,harmony, tone color,texture andform are the essential elements of music.We'll be exploring these elementsin our next several sessions.We'll start with rhythm becauserhythm provides a framework,a framework in time,one which sounds, pitches can rest.We all have rhythm of our lives anda beat, a heart beat.And of course there's a beat in music too.Most music has a regular pulse to it.Some music Gregorian Chant forexample doesn't have a beat.Here's a group of singers I organized someyears ago singing Gregorian Chant atYale University alongwith an image of a chantmanuscript fromthe Yale Rare Book Library.In thismusic, therereally isno beat.[MUSIC]Very beautiful, but no beat.Pop music usually has a very strong beat.That's one of the thingsthat makes it popular.We respond almost primordially to a beat.Here's an example of a poppiece with a strong beat andalso a strong back beat thathelps us emphasize the beat.It's a video created as a somewhatorganized or maybe disorganized flash mobor flash dance recently in the mainlibrary of Yale University.>> [NOISE] Hey, Macklemore,can we go to the shopping?[MUSIC]Pretty good, almost impossiblenot to tap your foot to that.In Classical music, there is a beat,but it's often suppressed.It's more subdued.The rock musician, Brian Eno,who worked with the Beatles once said,quote, classical musicis music without Africa.End quote.Meaning that music without a strongmusic profile.And for the most part, he was right.But here's an example of classical musicin which there is a pretty clear beat.Pomp and Circumstance March bythe classical composer Edward Elgar.You probably heard it at a graduation.[MUSIC]It's not surprising that in, in thisclassical music the beat is pronounced,because we're supposed to marchto it during graduate ceremony.I'd say that in Pomp andCircumstance we have a medium strong beat.But here's a much better example ofwhat I mean when I say Classical musicoften has a suppressed beat wherethe sound of the beat is weak.Indeed, where is the beat here?Can you tap your foot to it likeyou could with the Macklemore?Here's Debussy'sClair de Lune.[MUSIC]So, we've heard strong beat, medium beat,and very weak beat or suppressed beat.Beats come along in regular intervals.And are the same duration, regular beat.However, the western psyche doesn't likeextremes of undifferentiated anything.We group time into units of seconds,minutes, and hours to make sense of it.We group decades andcenturies into periods andcall them the Renaissance andthe Enlightenment to help us make sense ofwhat would otherwise bea seemingly endless flow of time.I'm convinced that in my Toyota automobilethe safety belt alarm goes ding,ding, ding, ding, ding, ding.Ding, ding,if I don't have my seatbelt fastened.So too in music, we group the endlessflow of beats to make sense of them.Here's an undifferentiated flow of beats.We can sound them with this gadget, andwe've been doing that sincethe time of Beethoven.[SOUND] Called of course a metronome andhere's what we instinctively do,we take these beats andgroup them into units of two.So here are the beats nowgrouped into units of two.Or, we can group them intounits of three and of four.But in fact, in most, butnot always, music written in four beatsis just a multiple of music in two beats.So really forour course we are going to have justtwo beat music and three beat music.Music in dupo or music in triple meter.Now I've just used the word meter there,when we group beats into regularlyrecurring units we create meter in music.Meter is simply a pattern ofregularly recurring beats.The lines that separate the groupsare called bar lines or measure lines.Each unit constitutes a bar or a measure.Bar lines tend to makewestern music on a grid.Other cultures don't havethis kind of grid andas a result their music isa good deal more flexible.But we in the west,we have these measure lines orthese bar lines and it's almost as ifyou can't break out from behind the bar,that you're kept inside of the measure.Okay.So we talked about beats andmeters and measures,your bars and bar lines.Now, let's take a look at this samematerial is a slightly different way.But before that,I've got a question for you.What are the two axes orcoordinates of music?Again, what are the two axes orcoordinates of music?Right.Pitch and duration.Otherwise said sound and time.Pitch is represented ona vertical axis in written form,and time on a horizontal one.Here's a graph to demonstrate this.Now, here's a score ofa piano piece by Beethoven.This musical score is justa complex version of thisprevious slide's simple idea.Pitch is indicated vertically,time horizontally.How do we get from this simpleidea of a two axes graph to thiscomplex version of musical notationthat you see on the screen?Well, we'll look at thatin our next segment.[MUSIC]