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 both critical thinking skills and vocabulary.

Each lesson is presented on one page, showing four possible culprits for a crime or misadventure. Students need to read a few paragraphs about the situation. These usually include the statements of observers along with some data points. Students then read brief statements from each of the suspects to gain 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. They are told to assume that the facts related by a witness or suspect are true statements. However, some statements are merely opinions, and students need to distinguish between fact and opinion to weigh the value of the statements.

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).

Each book has twelve lessons, so older students can easily complete both books in one year using one lesson per week and have time left over. For students in grades seven through twelve, having them look up unfamiliar words and figure the mysteries out on their own should suffice for the study of vocabulary if students complete both books. You might have younger students complete only one book per year. Many of the words are challenging, so you will have to judge whether the level of the vocabulary is even appropriate for your fifth or sixth graders. 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 them to write in the correct vocabulary words. The answer key includes a chart for each lesson showing 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.

These 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

Publisher's Info

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