How does the novel introduce the conflict between the Socs and greasers in The Outsiders?

The conflict between the greasers and Socs is introduced when Johnny and Pony meet the Soc girls at the movie theater. 

Pony gives us some background about the differences between greasers and Socs before going to the movies.  He explains that greasers are in danger from Socs. For this reason, he is nervous about walking without his gang. 

Greasers can't walk alone too much or they'll get jumped, or someone will come by and scream "Greaser!" at them, which doesn't make you feel too hot, if you know what I mean. We get jumped by the Socs… the jet set, the West-side rich kids. (Ch. 1) 

At the movies, Pony and his friend Johnny, another greaser, meet two Soc girls named Cherry and Marcia.  The girls are kind to Johnny and Pony, but do not like Dally.  Dally behaves crudely toward them and Johnny stands up for them.  Cherry asks Pony why he is friends with someone like Dally. 

Cherry was looking at me. "What's a nice, smart kid like you running around with trash like that for?"

I felt myself stiffen. "I'm a grease, same as Dally. He's my buddy." (Ch. 2) 

Although Cherry apologizes, this incident helps the reader understand the Socs perception of greasers.  There are no physical fights here, but there is still a class conflict.  The girls are there without their boyfriends because their boyfriends were drunk.  They know that the boys would not approve of them hanging out with greasers, but they personally do not mind the greaser boys.  Cherry and Pony discuss what they have in common. 

The conflict comes to a head when they are leaving, and the Soc boys return.  The girls know that there will be a problem with them hanging around with greaser boys.  Johnny is also frightened because Bob and his group jumped him before and hurt him badly.  The girls avoid a fight by going with the Soc boys, but that is not the end of it.  Bob and Randy later fight Pony and Johnny in the park.