Setting the Mood
Somber. Nostalgic. Joyous. Depressing. Curious. If you've felt it, there's a poem that matches that mood. When you're feeling sappy and sentimental and you reach for the greeting card that expresses your mood, there's probably a little poem on the inside, next to the softly lit photos of flowers and kittens. The poem, probably 8 rhyming lines, perfectly captures your mushy feelings, but how does it do it? The writers of those cards know that there are some tools in the poetry tool kit that create mood. The main three are images, sounds, and diction.
Imagery
Imagery in poetry is the parts that excite the senses. Poetic imagery comes in several varieties. The most common is visual imagery, but poets can create images that appeal to touch, taste, smell, or hearing. There's a reason why flowers and kittens appear on your greeting card. Those images elicit an emotional response. Well, images in a poem do the same thing. Writers choose their images based in part on the mood they create.
In Poe's poem, The Raven, he presents the reader with some carefully constructed images. Poe builds his mood of melancholy from the early in the poem when he describes a fire in a fireplace in the midst of winter. Rather than focus on the cheerful flames or the cozy warmth, he instead references the embers thrown from the fire that glow and are then extinguished. Poe writes, 'And each separate dying ember wrought its ghost upon the floor'. Even the dead embers are described in ghoulish terms by Poe's use of the word 'ghost.'
Diction
And that brings me to my second tool, diction. Diction in the context of poetry simply means the words chosen for a poem. Words carry emotional weight. Poets first decide on the emotion they're hoping to create in the reader and then they choose words to build their images, metaphors, and all those cool poetic devices you've learned about in class. Well-chosen words will carry additional emotional content that augments the intended mood of the poem.
For example, rather than using a word like 'fading' or 'burning' to describe the embers, Poe chooses the word 'dying', a word that carries sadder emotional content than the others. Instead of 'ashes', Poe employs the word 'ghost' to refer to the remnants of the embers. His creepy, supernatural diction supports his poem's mood, which is both melancholy and creepy.