Elementary, My Dear Watson. It's Deductive Reasoning! (Grades 5-10)

Graphic: Andrew Ault

It's a rare phenomenon when a literary character jumps off the pages of a book and takes on a life of his own. Sherlock Holmes, whose birthday is today, is one such character. People still flock to 221B Baker Street to see where Holmes shared his flat with Dr. Watson. The stories about Holmes are studied, enacted, and most of all enjoyed by a countless number of people who admire his remarkable gifts of observation and deduction. The first ("A Study in Scarlet") of the intriguing tales concerning Sherlock Holmes was published in 1887; the last ("Shoscombe Old Place"), in 1927.

Sir Arthur Conan Doyle, who created Holmes, displayed his own keen intelligence in the 56 short stories and four novels that recounted the genius of Sherlock Holmes. Doyle was born in Scotland in 1859--which, by the way, would make him five years younger than Holmes. While studying to become a doctor, Doyle became greatly impressed by the ability of one of his professors, a surgeon, to use deductive reasoning to uncover information about patients. Doyle modeled Sherlock Holmes on this doctor, as well as on another professor who taught forensic medicine.

"You see, but you do not observe." Sherlock Holmes directed that statement to Dr. Watson, but it could easily be used in describing many people. Observation and deduction are skills that must be developed by using them in real-life situations. Today's students need to be given experiences that enable them to practice and develop these skills so that they may use them to relate and interact with the world around them.

(For those of you purists, it's true that Sherlock Holmes never said, "Elementary, My Dear Watson," in any of the stories. Blame it on the movies!)

Connections

Sherlock Holmes was a master detective. Students can tell you about the skills a detective needs, but do they know how to use those skills in their own lives? Read one of Doyle's stories to the class, or have students read the story, and discuss how Holmes works through his thought processes while solving the crime. (Be aware, in case it has been a while since you have read a Sherlock Holmes story, that Holmes sometimes took drugs such as cocaine. Two works--"Sign of the Four" and "A Scandal in Bohemia"--make direct references to his use of drugs. This reminder is included here to give you time to think about the best way to handle the subject before it comes up.) Can the students name other characters who practiced deductive reasoning? Can they identify situations where this type of thinking has been or could be useful? This is also a good opportunity to introduce the topic of inductive reasoning.

As some of the resources listed below illustrate, the stories about Sherlock Holmes can be used to help demonstrate deductive reasoning in math and science.

A way to connect deductive reasoning to a study of history is to examine how societies have looked at problems and then developed solutions. Select a time period and assign students a problem that a group of people from that period had to solve, such as how to provide fresh water in a walled town during a siege. Ask students to imagine some of the thought processes the inhabitants might have gone through before coming to a solution. Have them specify examples of deductive reasoning.

Especially for younger students, the concept of deductive reasoning might be a bit abstract. You might start with a class game of 20 questions or Clue to get across the initial idea. Then have students make deductions about a well-known person, starting off with very general assumptions and moving toward more specific ideas.

Web Resources

1. Who Dunnit?
   
   http://www.cyberbee.com/whodunnit/crime.html
   (An ENC Digital Dozen selection, ENC#019798) Grades 6-9. This site could as easily be listed in the Ready-to-Go Activities section below. It's a fun site where students learn about being a forensic scientist and get to solve crimes such as determining who took a bite out of the candy.
   
   
2. The Sherlock Holmes Museum
   
   http://www.sherlock-holmes.co.uk/home.htm
   Grade 7+. How often can you visit the home of a literary character? Well, this site takes you to 221B Baker Street--this virtual tour is the next best thing to being there. Middle school students on up would enjoy this site.
   
   
3. The Baker Street Connection
   
   http://www.citsoft.com/holmes3.html
   The full text of the 56 short stories and four novels written about Sherlock Holmes is available on this site.
   
   
4. A Little of Sherlock Holmes
   
   http://www.geocities.com/Athens/Delphi/4040/sherlock.html
   This question-and-answer site will give you and your students a great deal of information about Sherlock Holmes and Dr. Watson. This is a great place to gain those interesting tidbits that spark discussions in your classroom.
   
   
5. The Sherlock Holmes Society of London
   
   http://www.sherlock-holmes.org.uk
   Learn about the movies and plays based on the famous Sherlock Holmes stories and find out about the events that happen worldwide to celebrate the famous detective.
   
   
6. Literature in High School Math
   
   http://www.enc.org/features/focus/archive/mathlit/
   You'll find really interesting, energizing ideas here for integrating literature into high school math classes. The three articles that form the nucleus for this ENC Focus feature are "Bringing Literature into the High School Math Class," "Launching Mathematical Investigations with Literature," and "Using Picture Books in High School Math."
   
   

Ready-to-Go Activities

1. Logical & Mathematical Puzzles
   
   http://puzzle.dse.nl/math/index_us.html
   Grades 7-12. This site provides fun puzzles and brainteasers that require a variety of thinking strategies.
   
   
2. Improving Deductive Reasoning Skills
   
   http://youth.net/cec/cecmath/cecmath.22.txt
   Grades 7-12. Lesson plan that uses Sherlock Holmes stories, deductive reasoning, and cooperative learning.
   
   
3. A Visual Approach to Deductive Reasoning
   
   http://illuminations.nctm.org/lessonplans/9-12/reasoning/
   Grades 8-10. Lesson plan that focuses on the use of Venn diagrams to hone reasoning skills.
   
   
4. Brain Teasers
   
   http://www.eduplace.com/math/brain/index.html
   (An ENC Digital Dozen selection, ENC#004499) Grades 3-8. New questions every week, one for grades 3-4, one for grades 5-6, and one for grades 7-8.
   
   
5. Searching for Solutions
   
   http://gouchercenter.edu/jcampf/searching_for_solutions.htm
   (An ENC Digital Dozen selection, ENC#018227) Grades 5-10. Click on "Process" to find a number of thoughtful math problem-solving exercises, such as "Finding a Pattern" and "Working Backward."
   
   

Classroom Resources from the ENC Collection

1. Prealgebra makes sense. Patterns of factors and multiples: interactive tasks for algebra learners
   Date: 2001 Grade(s): 6 - 8 Cost: $4.95 - $9.95 ENC#: 026866
   The problems in this pre-algebra workbook will exercise and stretch your students' reasoning abilities.
   (For more details see ENC Record)
   
   
   
2. Catch them thinking: a handbook of classroom strategies
   Date: 1993 Grade(s): 4 - 12 Cost: $29.95 ENC#: 019611
   This book presents crime scene science labs that you can use to supplement your science curricula. Problem-solving skills and concepts are incorporated into lessons to help guide the student toward a solution. The lessons emphasize the idea that solutions to real-life problems require knowledge from a variety of sources.
   (For more details see ENC Record)
   
   
   
3. Logic number problems
   Featured in ENC Focus  
   Date: 1987 Grade(s): 7 - 12 Cost: $11.95 ENC#: 011375
   The emphasis of these 50 problems is on problem-solving concepts and thinking skills.
   (For more details see ENC Record)
   
   
   
4. Mystery in room one~eleven
   Date: 1994 Grade(s): 5 - 8 Cost: $24.99 ENC#: 008955
   This unit on problem solving starts in the English class, moves to math and then to science, and ends in the social studies class. It was created by middle school teachers, and its interdisciplinary approach covers a wide range of middle school curricula. It would be a great end-of-the-year activity.
   (For more details see ENC Record)
   
   
   
5. Problem solving through critical thinking
   Date: 1990 Grade(s): 5 - 8 Cost: Out of Print ENC#: 003610
   This book presents 18 high-interest problems that require the student to use computational, problem-solving, reasoning, and communication skills. Students will enjoy the dilemmas presented to them.
   (For more details see ENC Record)
   
   
   
6. Detective science: 40 crime-solving, case-breaking, crook-catching activities for kids
   Date: 1996 Grade(s): 4 - 8 Cost: $12.95 ENC#: 017691
   Students will become so interested in what they're doing as they take on the role of a forensic scientist, they won't even know they're learning the skills used in scientific inquiry.
   (For more details see ENC Record)
   
   
   
7. Be a codebreaker!: mystery messages to puzzle over and decipher
   Date: 2000 Grade(s): 5 - 8 Cost: $9.00 ENC#: 026665
   This is a fun book that hones students' reasoning abilities. At the front of the book, there are tips for solving cryptograms. But solving the cryptograms is not the whole story. Students use the decoded messages to find buried treasure and to solve word puzzles.
   (For more details see ENC Record)
   
   
   
8. Mind benders C1: deductive thinking skills
   Date: 2002 Grade(s): 8 - Post-Sec. Cost: $9.99 ENC#: 026672
   Here are 14 exercises in deductive reasoning, each one of which is accompanied by a chart that students can use to organize information provided by a number of clues. The exercises are definitely mental workouts--too difficult for younger students--but are very satisfying when solved! The last section of the book explains the solutions.
   
   This book is part of a series. Other books, for example, Mind Benders A1 (for grades 2-12) and Mind Benders B1 (for grades 6-12), offer similar exercises and are meant to include younger students. The execises seem quite difficult, though, and if you were to use them with early grades, it might be best to do the problems as a class. To see the A series books, check ENC#026510, 026511, 026512, and 026513. For the B series, see ENC#026514, 026515, 026516, and 026517.
   (For more details see ENC Record)
   
   
   
9. Easy math puzzles
   Date: 1997 Grade(s): K - 3 Cost: $15.95 ENC#: 014024
   Even though the age group specified for this book is young, students in fourth, fifth, and even older grades will have fun reasoning out the answers. You can also have students use it as a model for creating their own book of puzzles.
   (For more details see ENC Record)
   
   
   

Search Strategies

Find more materials by searching Curriculum Resources on ENC Online using these terms: Deductive reasoning or Logical reasoning.

Connections to Standards

Realizing that there are many ways to use this Classroom Calendar entry, we chose these standards because they relate to the entry, in full or in part. If you want to explore the standards further, please use the link(s) provided.

Connections to NCTM Standards
Communication: Organize and consolidate their mathematical thinking through communication
Communication: Communicate their mathematical thinking coherently and clearly to peers, teachers, and others
Communication: Analyze and evaluate the mathematical thinking and strategies of others
Connections: Recognize and apply mathematics in contexts outside of mathematics
Data Analysis and Probability: Understand and apply basic concepts of probability
Data Analysis and Probability: Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them
Data Analysis and Probability: Select and use appropriate statistical methods to analyze data
Data Analysis and Probability: Develop and evaluate inferences and predictions that are based on data
Problem Solving: Monitor and reflect on the process of mathematical problem solving
Problem Solving: Build new mathematical knowledge through problem solving
Problem Solving: Solve problems that arise in mathematics and in other contexts
Problem Solving: Apply and adapt a variety of appropriate strategies to solve problems
Reasoning and Proof: Select and use various types of reasoning and methods of proof
Reasoning and Proof: Recognize reasoning and proof as fundamental aspects of mathematics
Reasoning and Proof: Make and investigate mathematical conjectures
Reasoning and Proof: Develop and evaluate mathematical arguments and proofs