Writing about things

"What is a concrete noun?" a student might ask.
"It's something you can drop on your foot," I always answer. "It's that simple."
"So if I am writing about markets, productivity and wealth, I am going to...."
"Yes indeed -- you are going to write about things you can drop on your foot, and people, too. Green peppers, ears of corn, windshield wipers, or a grimy mechanic changing your car's oil. No matter how abstract your topic, how intangible, your first step is to find things you can drop on your foot."
From a teacher's perspective, the lovely thing about this technique of writing with things you can drop on your foot is that both the skilled and the unskilled can do it. Both kinds of students find the assignment intriguing. Students led into writing this way at the start of a course--writing about abstract ideas in terms of concrete objects--find it strange at first, but they are pleased that the task is actually doable. They start to write with good examples, though they don't think of them as examples, but as objects.(John Maguire at The Atlantic)