Deductive reasoning is an essential academic skill for students of all grade levels to practice. Activities that help students develop deductive reasoning can be implemented to complement many areas of the curriculum. As students engage in engaging deductive reasoning activities, at first they practice using logic to draw conclusions based on evidence. Eventually students may study how deductive reasoning can be used to persuade or manipulate people.
Guess the Coin
Give students clues about which coin you are thinking of as students narrow down the possibilities using deductive reasoning. Place a quarter, nickel, dime and penny in front of students. Tell them to keep track of the clues until they know which coin you are describing. First, say that the coin you are thinking of is silver. Next, say that the coin you are thinking of is not the largest coin. Finally say that the coin you are thinking of is larger than a dime. Students should narrow down the possibilities and have confidence that you are describing the nickel. This activity works well for young students who are just beginning to focus on using deductive reasoning to form a conclusion based on multiple elements.
In this detective activity students use deductive reasoning skills to piece together a timeline of facts gathered, forming a hypothesis to solve a mystery. Provide small groups of students with two evidence envelopes, each filled with fact strips describing single events that solve the mystery. Have students open one envelope and read over the facts, placing them in sequential order and forming a hypothesis to solve the mystery. After students have discussed their ideas, decided on a timeline and formed a hypothesis, allow them to open the second batch of evidence. Students now revise their original timeline and hypothesis to account for the new facts, learning that it is important to consider all facts before jumping to a conclusion.
Teach students to differentiate between inductive and deductive reasoning by having them draw conclusions based on both types of reasoning. Introduce inductive reasoning as using specific observations to draw a general conclusion. For example, if Jim enjoys ice skating, skiing and snowshoeing, one could use inductive reasoning to conclude that Jim likes cold weather. Remind students that inductive reasoning may lead to a strong hypothesis, but it is not always going to draw a truthful conclusion. Explain that deductive reasoning starts with multiple known facts and combines them to make a new statement that must be true. For example, if all eighth grade students must take a math class, and Ted is in eighth grade, one can deduce that Ted takes math. Have students practice writing examples of inductive and deductive reasoning to create claims about their classmates.
Dystopian Literature Propaganda
Older students can practice manipulating logic constructed by deductive reasoning to create propaganda related to a dystopian novel they are reading. Many dystopian novels include an oppressive governmental body of some kind and a brainwashed citizenry. Have students jump into the mind-set of the governing body in the book and create a poster using a flawed example of deductive reasoning, such as “ignorance is bliss; schools prohibit ignorance; therefore, schools prohibit bliss.” This activity teaches students to be wary of arguments that contain logical fallacies, especially in advertising or propaganda, where words are used to manipulate people into thinking or acting a certain way.
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