Teachers all over look to Gerald G. Duffy, EdD, for his expert advice on how to teach reading, and part and parcel of Duffy's reading strategies is his focus on vocabulary. In this excerpt from his best-selling text Explaining Reading, Duffy demonstrates how semantic maps can help students visualize how word meanings can be categorized.

As students progress in school, subject matter becomes more complex. Correspondingly, word meaning becomes more complex.

It becomes more and more difficult to provide direct experiences with new words because, instead of learning words by directly experiencing them, it is much more typical for new concepts to be learned through vicarious experiences. That is, we read about the new words and talk about the new words, but we do not directly experience them.

Second, vocabulary learning becomes more complex as kids progress through the grades because words are organized into categories and subcategories. While organizing ideas and concepts according to categories is "natural" in the sense that good verbal learners all do it, learning to categorize can be complex and difficult for some students.

Semantic mapping is one way to explain how to categorize word meanings. It remains essential to identify key attributes distinguishing one word from another. But semantic maps provide the additional benefit of helping students visualize how word meanings can be categorized. The following is an example of how this might be done.

This example assumes a third/fourth-grade combination. Students are working together on a science unit on rocks. Their ultimate goal is to take a trip to a local museum and to be able to identify the different rocks on display there. As part of their study of rocks, the teacher orally reads Joanna Cole's The Magic School Bus: Inside the Earth (Scholastic, 1987). In the discussion following the teacher's reading of the book, it is clear that students cannot distinguish among the various categories of rocks. The teacher decides to provide an explanation of how words can be organized into categories as a means for enriching word meanings.

Lesson Introduction

Say something like: "In The Magic School Bus story we just heard, Ms. Frizzle and her students found lots and lots of rocks. It is hard to remember the names of all those rocks. Let me show you how I remember these new words. The secret is to think about how they are alike, to think about how they are different, and to think of a single box with a single name that we could put certain words in and another box that we could put other words in. Let me show you how I do it with the first three words and then you can try it with other words."

Modeling the Thinking

Say something like: "When I am trying to understand the meaning of words like sandstone, shale, and limestone, I try to build a picture in my mind of how the words are alike and how they are different, and then I try to decide if something is an example of one of the words. I can map the picture in my mind like this. I think to myself that sandstone, shale, and limestone are all rocks. So they are alike in that way, and I can show it this way:

"But Ms. Frizzle said in the book that they are also alike because they are all 'sedimentary' rocks. So, I can show that like this:

"So, I can say that these three rocks are alike because they are all sedimentary rocks. My map of the words helps me with that. Now I have to think about how these three rocks are different. One way they are different is that they are different colors. Sandstone is tan, shale is gray, and limestone is white. So, I can add to my map like this:

"But I learned from the book that these three rocks are also different because of what they are made of. Sandstone is made of sand pressed together, shale is made of mud pressed together, and limestone is made of shells pressed together. So now I can add those to my map.

"So now I can tell which rock is which. They are all sedimentary, but sandstone must be tan and is made of sand all pressed together; shale would be rock that is gray and is made of mud all pressed together; and limestone would be rock that is white and is made of shells all pressed together.

"By looking for how the words are alike and how they are different, and then using that information to decide which is which, I am able to use the words correctly when I am talking and writing about rocks or trying to tell one rock from another."

Scaffolded Assistance

Example 1: Extensive Teacher Help

Say something like: "Remember when the bus sprouted a drill and went deeper into the earth? They found a different kind of rock down there. It was called 'metamorphic' rock. So I would have to put that on my map next to 'sedimentary.'

"So, then you need to think to yourselves, what rocks are 'metamorphic' rocks? Yes, marble and slate are both metamorphic, so I can put them on my map like this:

"So, how can you tell that a rock is marble or slate? I'll read this section to you again, and then we'll put what we find on our map. Yes, marble is harder limestone, and slate is harder shale. So let's put that on our map.

"So, how would you decide if a piece of rock was marble? Would it have to be hard? Would it have to look like the color of limestone? Yes. It cannot be marble unless it is very hard and unless it is a color like limestone."

Example 2: Less Teacher Help

For a second level of assistance, you might continue to build the semantic map for rocks, using the igneous rocks described next in the book. This time, however, you would provide less direction. Say something like: "As Ms. Frizzle and the kids went deeper into the earth, they found another kind of rock. Let me read this section to you again, and then we will fill in the map together."

Example 3: No Teacher Help

At a third level of assistance, you may reread the section in the book on volcanic rock, remind the students to think about how these rocks are similar and what they would put on the map, how they differ from each other and how they would put that on the map, and how they would use what is on the map to determine what a particular rock is an example of. But you would leave it to them to do the actual categorizing.

Application in Reading

This lesson illustrates how explanations can be applied after a selection has been read. Because this is a unit on rocks, the teacher will present other books and articles to the students that contain the names of various kinds of rocks. In such future reading situations, the semantic map constructed in this lesson can be used to distinguish the various kinds of rocks.

How Will You Know the Lesson Has Been Successful?

You will know the lesson has been successful if, in subsequent discussions during the unit on rocks, students use the new vocabulary words correctly in their oral discussion and in their writing.

Application in Writing

Vocabulary is strengthened by use. The more the new words are used, the more they are solidified in the mind. Vocabulary is particularly strengthened when new words are used in writing. Consequently, we should look for opportunities to have students use the new vocabulary words in their writing.

From Explaining Reading, Second Edition: A Resource for Teaching Concepts, Skills, and Strategies, by Gerald G. Duffy. Copyright 2009 by Guilford Press. All rights reserved. Reprinted with permission of Guilford Press.