Day 6: Selection (Conditionals)

Learning Objectives

• AAP-2.E: For relationships between two variables, expressions, or values: Write expressions using 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 do programs make decisions based on conditions?
• How can we use conditional statements to control program flow?

Materials Needed

• Presentation slides on selection statements
• Programming environment
• Conditional statement worksheets
• Flowchart templates
• Exit ticket templates

Vocabulary

• Selection
• Conditional statement
• Boolean expression
• If statement
• If-else statement
• Branching
• Control flow
• Decision
• Block

Procedure (50 minutes)

Opening (8 minutes)

1. Review and Connection (3 minutes)

   • Review algorithm design and testing from previous lesson
   • Connect to today's focus on making decisions in programs

2. Warm-up Activity (5 minutes)

   • Present a real-world scenario that involves decision-making
   • Ask students to describe the decision process in their own words
   • Discuss how decisions can be represented as yes/no questions

Main Activities (32 minutes)

3. Lecture: Selection Statements (12 minutes)

   • Define selection as a programming construct that executes different code based on conditions
   • Explain the structure and syntax of conditional statements:
     • IF (condition)
     • IF (condition) { statements } ELSE
   • Discuss Boolean expressions as conditions that evaluate to true or false
   • Explain how relational operators (=, ≠, >, <, ≥, ≤) are used in conditions
   • Show how the program flow changes based on condition evaluation
   • Demonstrate the execution of IF and IF-ELSE statements with examples
   • Explain the concept of blocks of statements in conditionals
   • Discuss common use cases for conditional statements

4. Demo: Implementing Decision-Making in Code (8 minutes)

   • Walk through examples of programs that use conditionals:
     • Determining if a number is positive, negative, or zero
     • Checking if a user is eligible for a discount
     • Validating user input
     • Implementing game logic
   • Show how to trace the execution of conditionals step by step
   • Demonstrate how different inputs affect the program flow
   • Highlight common mistakes in conditional statements

5. Hands-on: Writing Programs with Conditional Statements (12 minutes)

   • Students work in the programming environment
   • Guide students through creating programs that use conditionals
   • Have students implement programs for scenarios like:
     • Determining if a year is a leap year
     • Calculating grades based on scores
     • Implementing a simple calculator with different operations
     • Creating a simple game decision
   • Encourage students to test their conditionals with different inputs

Closing (10 minutes)

6. Activity: Creating a Simple Decision-Making Program (5 minutes)

   • Students design and implement a program that makes decisions based on user input
   • The program should use both IF and IF-ELSE statements
   • Students should test their program with various inputs
   • Share and discuss different approaches

7. Exit Ticket and Preview (5 minutes)

   • Students complete a program that uses conditional statements to solve a problem
   • Preview that next class will focus on Boolean logic and compound conditions

Assessment

• Formative: Quality of conditional programs during hands-on activities
• Exit Ticket: Correctness and effectiveness of conditional program

Differentiation

For Advanced Students

• Provide more complex decision scenarios
• Introduce the concept of nested conditionals
• Challenge them to optimize decision structures

For Struggling Students

• Offer more structured templates for conditional statements
• Provide flowcharts to visualize decision-making
• Focus on simpler conditions before moving to complex ones

Homework/Extension

• Complete a worksheet with conditional statement exercises
• Create a program that implements a more complex decision-making scenario
• Research how conditionals are used in real-world applications

Teacher Notes

• Emphasize that conditionals change the sequential flow of program execution
• Watch for common syntax errors in conditional statements
• Make connections to algorithm design and how conditionals implement decisions
• Consider using physical demonstrations to show branching paths
• Remind students that selection is one of the fundamental programming constructs