What are the differences(content wise) between country music and blues music?
What are the differences, as far as lyrical content, in the way emotions are expressed. e.g both can express downheartedness but in what way do both genres differ in how they are conveyed.
Musically, country tunes are built a lot of times on four chords, whereas basic blues songs use three. Often times in blues and country, you are dealing personality and physical characteristics of a female, or male. Then it depends on how the song goes. so blues and country are both kinds of folk music, as is most world music.
Blues is the central part of the African American musical tradition and as such is the foundation for rock, R&B, etc. The blues have distinctive chord progressions and half-tones that make it different from traditions like European classical music. See specifics here: http://en.wikipedia.org/wiki/Blues
Lyrics are usually ballads of lamentation or longing (thus ‘the blues’).
Blues and country in their early development had much interaction since both developed at similar times in the American South. Although there was much segregation, there was enough interaction between communities – especially in working class jobs — to make the traditions closely related in the early Twentieth Century at least. Country has also historically had more influence from English, Irish, and Scottish ballads brought over by immigrants to America.
Today, they have branched apart, with country melding much more with pop.
There is still an emphasis in country on vocal performance and still a little "twang." But honestly, what makes a Taylor Swift song a country song and not a pop song has more to do with marketing than musicology.
Folk: technically, any traditional music of a community may be considered folk music (the musical equivalent of folklore), so blues and country are both kinds of folk music, as is most world music. But at the music store, what they call folk is just singer-songwriter acoustic music usually inspired by the "folk" revival of the 1960′s and 70′s.