Rhythm is quite literally the heartbeat of a poem and serves as the backdrop from which the ideas and imagery can flow. Rhyme is the musicality behind the words and the way the phrases come together. These two elements represent the framework of poems and the techniques that set poetry apart from other prose writing.
Rhythm creates the pattern of language in a line of a poem, marked by the stressed and unstressed syllables in the words. A foot in poetry refers to a stressed/unstressed syllable, and meter counts the number of feet in a line. The most famous rhythm is iambic pentameter, which is found in most of Shakespeare's writing. The word iamb means the foot is in the pattern of unstressed/stressed, and pentameter means there are five feet, or sets of syllables in each line.
Why is Rhythm Important?
Rhythm is essential to poetry because it is a mirror of life. Nature expects a rhythm, as evidenced by the change from day to night, or the order of the seasons. This contributes to the pleasure of the reader; rhythm is what we expect from music, from nature, and certainly from poetry. Cacophony opposes rhythm, and is abrupt to the ear.
Rhyme is the matching up of sounds and syllables, usually at the end of lines. External rhyme is the rhyming of words at the end of lines. Shel Silverstein's poetry is a great example of this. And "The Raven," by Edgar Allan Poe, incorporates internal rhyme in "Once upon a midnight dreary, while I pondered weak and weary." This means that two words rhyme within the same line, in this case dreary and weary.
Why is Rhyme Important?
Rhyme functions in much the same way as rhythm. It keeps the poem in harmony, and a rhyme scheme helps the audience to understand what is coming. Rhyme scheme can be figured by looking at the last word in each line and assigning a letter. The last word in the first line gets an "a." The last word in the second line, if it rhymes, also gets an "a." If a word does not rhyme, it gets the next letter, "b" in this case. Discerning the rhyme scheme is important because the pattern brings the poem to life and helps the audience feel connected.