Determine what knowledge, if any, your fourth grade students have already gained throughout their time in school and at home. For example, design a short and simple pop quiz. You can also just ask questions and ask for volunteers to share their answers with the classroom.
Discuss concepts of alphabetical order and how they can be used to find the correct term in the dictionary. This will be a review for most of your fourth grade students, who will have already done some basic alphabetizing in earlier grades. However, applying the concept to the dictionary may be new.
Design practice for your students to hone their skills with the dictionary. If you are studying vocabulary words, assign a homework assignment as practice for your students to find two alternate definitions for their vocabulary words using two different dictionaries. You can also place words on the board and time students to determine how long it takes them to find each word.
Play games with your students to help them get a more complete understanding of a dictionary. Fourth graders want to show their creativity, so use Merriam-Webster's Word Central Build Your Own Dictionary tool to allow students to create their own words with definitions. This game will help them understand all of the different parts of the entries included in dictionaries, such as the word, the part of speech and the definition.