Day 7: Boolean Logic and Compound Conditions

Learning Objectives

• AAP-2.E: For relationships between two variables, expressions, or values: Evaluate expressions that use relational operators.
• AAP-2.F: For relationships between Boolean values: Write expressions using logical operators.
• AAP-2.G: Express an algorithm that uses selection without using a programming language.

Essential Questions

• How can we combine multiple conditions to make more complex decisions?
• How do logical operators allow us to create sophisticated Boolean expressions?

Materials Needed

• Presentation slides on Boolean logic and compound conditions
• Programming environment
• Truth table worksheets
• Debugging exercises with Boolean logic
• Exit ticket templates

Vocabulary

• Boolean expression
• Logical operator
• AND
• OR
• NOT
• Truth table
• Compound condition
• Short-circuit evaluation
• De Morgan's Laws

Procedure (50 minutes)

Opening (8 minutes)

1. Review and Connection (3 minutes)

   • Review basic conditional statements from previous lesson
   • Connect to today's focus on combining conditions

2. Warm-up Activity (5 minutes)

   • Present a scenario requiring multiple conditions (e.g., eligibility for a program based on age AND education level)
   • Ask students how they might represent this decision in everyday language
   • Introduce the concept of compound conditions

Main Activities (32 minutes)

3. Lecture: Boolean Expressions and Compound Conditions (12 minutes)

   • Review Boolean values (true and false) and relational operators
   • Introduce logical operators:
     • AND: true only when both conditions are true
     • OR: true when at least one condition is true
     • NOT: inverts a Boolean value
   • Explain the syntax for logical operators in the AP CSP pseudocode:
     • condition1 AND condition2
     • condition1 OR condition2
     • NOT condition
   • Demonstrate truth tables for each logical operator
   • Explain how to combine multiple conditions using logical operators
   • Discuss operator precedence in Boolean expressions
   • Show how parentheses can be used to control evaluation order
   • Explain common patterns and use cases for compound conditions

4. Demo: Using AND, OR, NOT Operators (8 minutes)

   • Walk through examples of programs with compound conditions:
     • Checking if a number is within a range (min ≤ x AND x ≤ max)
     • Determining if a student passes (score ≥ 60 OR hasExtraCredit)
     • Validating complex input (NOT (age < 18) AND hasParentalConsent)
   • Show how to trace the evaluation of compound conditions
   • Demonstrate how different inputs affect condition evaluation
   • Highlight common mistakes in Boolean logic

5. Hands-on: Writing and Evaluating Complex Conditions (12 minutes)

   • Students work in the programming environment
   • Guide students through creating programs with compound conditions
   • Have students implement programs for scenarios like:
     • Determining eligibility for a discount (senior OR student OR military)
     • Checking if a date is valid (validMonth AND validDay AND validYear)
     • Implementing game logic with multiple conditions
     • Creating a simple form validator
   • Encourage students to test their conditions with various inputs

Closing (10 minutes)

6. Activity: Debugging Conditional Logic Errors (5 minutes)

   • Provide students with code segments containing logical errors
   • Students identify and fix the errors
   • Common errors might include:
     • Using AND when OR is needed (or vice versa)
     • Incorrect use of NOT
     • Missing parentheses affecting evaluation order
     • Redundant conditions
   • Discuss the fixes and reasoning

7. Exit Ticket and Preview (5 minutes)

   • Students create a program that uses compound conditions to solve a problem
   • Preview that next class will focus on iteration (loops)

Assessment

• Formative: Quality of compound condition implementation during hands-on activities
• Exit Ticket: Correctness and effectiveness of program with compound conditions

Differentiation

For Advanced Students

• Introduce De Morgan's Laws for transforming Boolean expressions
• Provide more complex logical puzzles to solve
• Challenge them to optimize Boolean expressions

For Struggling Students

• Provide truth tables as reference
• Focus on one logical operator at a time
• Use visual diagrams to represent compound conditions

Homework/Extension

• Complete a worksheet with Boolean logic exercises
• Create a program that implements a decision system with multiple criteria
• Research how Boolean logic is used in database queries or search engines

Teacher Notes

• Emphasize the difference between AND and OR, which often confuses students
• Watch for common logical errors, especially with NOT and operator precedence
• Make connections to mathematical logic and set theory
• Consider using Venn diagrams to visualize AND and OR operations
• Remind students that Boolean logic is fundamental to computer science