An external conflict found in The Adventures of Tom Sawyer is the character vs. character conflict between Tom and his Aunt Polly.
Conflict is a struggle between opposing forces. An external conflict is a struggle between a character and an outside force, such as another character.
Aunt Polly wants to raise Tom right, but she has a hard time keeping control of him. Tom spends most of his time avoiding Aunt Polly, or trying not to get caught or punished. Aunt Polly loves Tom, and finds his antics funny.
“Hang the boy, can't I never learn anything? Ain't he played me tricks enough like that for me to be looking out for him by this time? But old fools is the biggest fools there is. Can't learn an old dog new tricks, as the saying is. (ch 1)
Of course, each time Tom runs away when she is about to hit him or lies to her, she gets upset but only until he makes her laugh. Thus while the two are in constant conflict, it is a friendly one. Even when Tom is punished for cutting school and lying about it, he manages to get out of his punishment—painting the fence—by tricking other boys into doing it.