Explain "butter" or "conk", and how it fits into the story The Watsons Go to Birmingham - 1963.

A "butter" or a "conk" is a hairstyle that was popular with some African Americans back in the 1960s.  It involved using caustic chemicals, sometimes lye, to straighten the hair so that it could be styled in different ways.  Getting a conk left the hair a reddish color, and, with the statement of rebellion it implied, might be similar to getting a Mohawk today.  Momma and Daddy do not approve of the hairstyle, believing that the chemicals used are harmful and that, in their son's case, the whole process communicates a desire to be something Byron is not.  Momma tells Byron,

"...is this straight mess more attractive than your own hair?  Did those chemicals give you better-looking hair than me and your daddy and God gave you?"

Byron got a conk out of a sense of rebellion, and because he thinks "it's cool".  He has succumbed to peer pressure - his best buddy Buphead has one - and Byron has decided to follow suit in direct defiance of his parents.  Byron's latest action is one in a long line of transgressions, and it is the last straw for his parents, who have tried everything to try to get their wayward son to make wise decisions in his life.  After Daddy shaves Byron's head as a punishment for his defiance, the family journeys to Birmingham, planning to leave Byron with his maternal grandmother for awhile and get him away from the bad influences of the city before he gets himself in real trouble.

The 1960s were a time of tremendous upheaval as African Americans struggled to gain their rights in society.  In this sense, Byron getting a conk relates directly to a central theme in the book in that it expresses, in Momman and Daddy's thinking, a kind of self-hatred on the part of blacks as concerns their race.  Byron says he wanted "Mexican-style hair", but  Momma and Daddy want their children to be proud of whom they are.  Interestingly, the conk soon went out of style, to be replaced by the Afro, a hairstyle that celebrates the natural attributes of the hair of individuals of African ancestry (Chapter 7).