How does the end of Act 2, Scene 2 contrast with the opening of Act 2, Scene 3 and why is it such a dramatic contrast?
The end of Act II, Scene 2, contrasts with the opening of Act II, Scene 3, just as the theme of Youth vs. Age sets up contrasts and the motifs of light/dark and day/night create oppositions.
Moreover, the entire drama of Romeo and Juliet is replete with contrasts: light/dark, violence/love impetuosity/patience choice/fate youth/age temperance/intemperance night/day
Whereas Romeo and Juliet are protected in the dark cover of night, Friar Laurence emerges safely in the early morning light to pick his herbs and flowers. He speaks cheerfully of the "morn" that "smiles on the frowning night"--a loving night in which Romeo and Juliet have enjoyed passionate exchanges, but fear the morning as with trepidation Juliet tells Romeo, "'Tis almost morning, I would have thee gone." On the other hand, Friar Laurence speaks in an opposing attitude as he remarks that the daytime will "cheer" up the world,
Now, er the sun advance his burning eye,
The day to cheer and night's dank dew to dry....
Such dramatic contrasts certainly underscore the violent love of Romeo and Juliet and embellish the imagery of this tragedy that is entirely a poem as it is written in its entirety in iambic pentameter with two sonnets included in the verse.