The basic idea of concrete examples is simple enough. You take a new concept that is complex for a student and you relate it to something that is simple for that student. For example, if you are teaching about soil conservation you would need to communicate a variety of complex vocabulary to students such as humus, topsoil, erosion, contour plowing, etc. In order for all of these abstract concepts and terms to make sense, it helps for students to relate them to what they already know.
You can compare the humus and topsoil to plant food because students understand the concept of food already. As you do this, it is important to then relate how the plants ‘eat’ their food. As you do this you can talk about how the plant roots help to hold the soil in place, like how a paper clip helps to hold papers together. From here, you can talk about how contour plowing slows erosion by plowing with the curves of the land. You can then go back to your paper clip example and put more paper clips along the edges of the paper. Your students will see that instead of being close in only one part, the paper will be close everywhere because there are many paper clips spread out along the papers’ edges all working together to hold it tight.
Paper clips holding paper together is the concrete example, while contour plowing helping reduce erosion is the abstract example. By explicitly linking the concrete example to the abstract one, you can help your students know and understand complex concepts.
However, this is not enough. It is also important to practice concreteness fading in your classroom. Concreteness fading is exactly what it sounds like. You begin to use more abstract examples over time.
For our above example, the concrete example is how a paper clip can hold a packet of paper together and a group of paper clips can hold a packet of paper together more effectively, similar to how contour plowing helps hold the soil in place. In order to start the concrete fading the teacher can use the same or a similar example, but this time there is no physical example, just a drawing. Then, after that, the teacher can simply refer to how contour plowing can reduce erosion.
This is, of course, a vast simplification of the process. But the pattern is essentially true. It is helpful to start with a concrete example that is already understood by your students. Then make it slightly more abstract. And move towards only having the abstract concept, because the abstract concept is often the goal of the lesson.