When developing this lesson for eighth graders, the teacher should explore the reason for the existence of these two rhetoric devices. In short, students should realize that the utility of similes and metaphors lie in their ability to produce complex meanings and ideas in a few words. By lesson's end, students should understand why an author used a simile or metaphor instead of explaining in less efficient terms the idea she wishes to convey.
Covering similes and metaphors simultaneously allows the teacher to relate two similar concepts. However, the teacher should remember to contrast the two devices. Impress upon students that similes show similarity in an explicit manner whereas metaphors implicitly express a situation of similarity. Metaphors pull the reader into an imaginative situation in which the reader has to draw the conclusion that the statement was not meant literally. Similes, which are more logical, state exactly the similarity meant to be expressed.
When teaching this lesson, take advantage of the two concepts being present at the same time. Show students how to translate between similes and metaphors. This task helps students gain versatility in their writing skills. Students develop the ability to choose how to express certain common similes and metaphors. This enables them to apply this knowledge in their own work, writing with novel sentences and descriptions, instead of relying on cliched set phrases.
The final goal of this lesson involves teaching students to create and use these devices. At this point, students have begun to write more abstract essays and reports, requiring them to use a larger set of rhetoric skills to express themselves. Require students to produce similes and metaphors of set situations. For example, show students pictures and ask them to produce similes and metaphors describing the scene or certain aspects in the picture.