Critical Thinking Detective: Vocabulary Series

Critical Thinking Detective: Vocabulary Series

The Critical Thinking Detective™: Vocabulary series is one of three strands of the Critical Thinking Detective series. The other two strands have books focused on critical thinking and math. The vocabulary strand has two books—both for grades five through twelve—subtitled Vocabulary Book 1 and Vocabulary Book 2. The format is the same in both books, and they provide about the same amount of work on critical thinking skills as on vocabulary.

Each lesson is presented on one page with four possible culprits for a crime or misadventure. Students need to read a few paragraphs about the situation that usually include the statements of observers and some data points. Students then read brief statements from each of the suspects that provide them with further information. There are a few exceptions to this format, such as one where the statements of the four suspects are provided, but they don’t say which statement comes from which suspect. Students have to piece together information from the various sources to eliminate the three innocent parties and identify the one that is guilty. Students are told to assume that everything they read in a lesson is a true statement. However, as they consider these true statements, they need to distinguish between fact and opinion to weigh the value of each statement.

Fifteen challenging vocabulary words are incorporated into each lesson, and students need to determine the meanings of the words in order to arrive at their conclusions. They will almost certainly need access to a dictionary as they try to decipher sentences such as, “The inciter was infamous in the school community for his recalcitrance with superiors and his loquaciousness with peers—especially in class” (Vocabulary Book 1, p. 12.)

As long as you have students look up unfamiliar words and figure the mysteries out on their own, this should provide sufficient vocabulary work for students if they complete both books over one school year. Many of the words are challenging, so you will have to judge whether the level is appropriate for your fifth or sixth graders—those at the lower end of the spectrum of grades for these books. For instance, among the words for the first lesson in Book 1 are credulous, madras, discrepant, puce, tenable, senescent, and spurious.

An activity page that faces each lesson page is to be used after students have solved the mystery. A box with the 15 vocabulary words is at the top of the page, and this is followed by sentences with blanks for students to write in the correct vocabulary words. The answer key includes a chart for each lesson that shows the vocabulary words and a synonym for each that applies in the context of the activity page sentences. These charts or words selected from the charts might be provided to the student as hints.

Each book has twelve lessons, so a student could easily complete both books in one year using one lesson per week. Books are available in print or as ebooks (printable books that are only readable on Windows systems). Answer keys with full explanations are at the back of each book.


I love the idea of incorporating vocabulary words into the mysteries. It gives students a reason to have to figure out the meanings of unfamiliar words. I hope The Critical Thinking Co. will produce more of these.

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Instant Key

  • Learning Environment: all situations
  • Grade Level: grades 5-12
  • Educational Methods: stories, puzzles, critical thinking
  • Technology: other ebook
  • Educational Approaches: unschooling or relaxed homeschooling, eclectic

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