In Act II, Scene iv of Romeo and Juliet, how does the character of the Nurse fulfill the role of comic relief?

In Act 2, Scene 4, s friends
make fun of Nurse and she teases Romeo.

means that after a
particularly dramatic moment, a character comes along that makes you laugh.  The nurse does this
throughout the play, because she makes bawdy jokes and is just generally cheerful.  Also, other
characters make fun of her occasionally.

Act 2, Scene 2 is a serious scene
becausehave professed their love for each other.  This is high drama in many ways.  First of all
you have the, ahh, thats romantic, touch.  Gushy romance goes a long way.  Its also a little
tense though, because Romeo and s families are fighting!  They should not even be
talking to each other, let alone kissing.  Uh, oh!  So that is dramatic,
because although the audience might be enjoying the tender romance, if they have been paying
attention they are also waiting for the other shoe to drop. 

There is a
little humor in Act 2, Scene 3, where the friar chides Rome for going from one girl to the next,
but it is mostly still dramatic.  He is reminding him of the consequences of his actions and
Romeo is professing his love to be serious.

Enter nurse.  She is kind of
bumbling and sweet, and tenderly devoted to Juliet but also a little bit obnoxious.  She is
perfect comic relief, a typical Shakespeare clown.

In Act 2, Scene 4, Romeos
friends make fun of Nurse (A sail, a sail!), and exchange bawdy conversation with her.  Romeo
gets impatient with this conversation, answering thus when she asks for him:

I can tell you; but young Romeo will be older when

you have found him than he was when you sought him. I

am the
youngest of that name, for fault of a worse. (Act 2, Scene 4)

Then, Romeo and the nurse exchange a witty conversation in which they tease each
other.  She makes fun of the fact that he is impatient to hear from Juliet, and that Juliet is a
sweet girl.  She also brings up Rosemary, the girl that he was supposedly in love with
before.

NURSE:

€¦Doth not rosemary and Romeo begin both with a

letter?

ROM:

Ay, nurse; what of that? Both with
an R.

NURSE:

Ah, mocker!
that's the dog's name.  (Act 2, Scene 4)

Ultimately, she
does tell him Juliet says yes, and arranges the meeting for him.  This little exchange is one of
the humorous moments in the play, and there are some. also provides comic relief, and so does
Romeo sometimes.

A play full of drama also needs some comedy.  Comedy andare
two sides of the same coin, life is full of both.  Any play needs a fair amount of comic relief
to give the audience some rest, and to balance out the tragic moments.  Shakespeare also wanted
to keep his audiences attention, and entertain them.  They would know whenever they saw Mercutio
or the nurse (or a sword) that some fun was coming!