In the poem to a daughter leaving home what is the central purpose and what is a good theme to use for this type of poem.i am trying to interpret...

Are you referring to the poem by Linda Pastan? If so, I
think this is a poignant little poem. The speaker is a mother whose daughter is leaving
home for the first time. The mother is remembering back when her daughter was only eight
years old. The poem is a metaphor comparing a bike-riding lesson to the girl leaving
home. When the mother was teaching the girl to ride her bike, she was also, in a
metaphorical sense, "taking off" to go on her own. Now that she is leaving home, she is
also "taking off" on her own. The mother's sadness now at her leaving is contrasted with
her excitement way back when the daughter was only 8 and learned to ride the bike by
just going for it. Her daughter's hair on the bike that day was waving in the breeze,
like what she now imagines is a handkerchief "waving goodbye" (this is a
simile).

Do you see how the poet skillfully blends her
images - the bike ride, the leaving home, the daughter's hair, the
handkerchief?

I am not sure what you assignment is, but if
you need to write something about the theme of this poem based on your own experience,
can you remember what it was like for you when you left home? You are in college, so
perhaps you are attending a college away from home and can relate to how your mother
felt when you left. You could compare this poem to your own experience, or perhaps write
a poem of your own that reflects the same theme.

If your
life experience is nothing like this bit of nostalgia, you could still use the theme,
only your experience would be different. I once was reminiscing about how sad my mother
was when she dropped me off at my college dorm, and my husband's experience was very
different - his parents were glad to see him leave home. Sad, but still something to be
used for literature.

Good luck.