People who study language call comparisons that use "like" or "as" similes and call direct comparisons metaphors. Second graders don't need to know the definition of a simile or a metaphor, but it is good to know that there are different kinds that you, as an author, use in different ways.
Comparisons with "like" or "as" are often easier to understand and write. Direct comparisons often take more thinking, and make your reader stop and think exactly what you mean. What does it mean that I am a robot in the morning?
In writer's workshop, we used comparisons in the invented folk tales we are writing. We also made a couple of lists that compare things that are stinky, sweet, and hot. What is something in your life you could compare?
