Day 1: Introduction to Algorithms

Learning Objectives

• AAP-1.A: Represent algorithmic processes without using a programming language.
• AAP-2.A: Express an algorithm that uses sequencing without using a programming language.

Essential Questions

• What is an algorithm and how do we represent it?
• How do algorithms help us solve problems in computing and everyday life?

Materials Needed

• Presentation slides on algorithms
• Handouts with everyday algorithms
• Flowchart and pseudocode templates
• Markers and large paper for algorithm visualization
• Exit ticket templates

Vocabulary

• Algorithm
• Pseudocode
• Flowchart
• Sequence
• Step
• Input
• Output
• Deterministic

Procedure (50 minutes)

Opening (10 minutes)

1. Welcome and Introduction (5 minutes)

   • Introduce the Algorithms and Programming Big Idea in AP CSP
   • Explain that this is the third of five big ideas in the course
   • Share the learning objectives for the unit
   • Connect to previous units (Creative Development, Data)

2. Activating Prior Knowledge (5 minutes)

   • Ask students: "What do you think an algorithm is?"
   • Have students share examples of algorithms they might use in daily life
   • Create a class definition of "algorithm"

Main Activities (30 minutes)

3. Mini-Lecture: What is an Algorithm? (10 minutes)

   • Define algorithm: a finite sequence of instructions to solve a problem or accomplish a task
   • Explain key characteristics of algorithms:
     • Precise and unambiguous steps
     • Finite number of steps
     • Produces a result or accomplishes a task
     • Deterministic (same input always produces same output)
   • Discuss examples of algorithms in everyday life:
     • Recipes
     • Directions to a location
     • Assembly instructions
   • Explain the importance of algorithms in computing

4. Activity: Develop Algorithms for Everyday Tasks (10 minutes)

   • Divide students into small groups (3-4 students)
   • Assign each group an everyday task (e.g., making a sandwich, tying shoes, etc.)
   • Groups develop detailed step-by-step algorithms for their task
   • Emphasize the need for precision and clarity
   • Have groups exchange algorithms and attempt to follow them exactly
   • Discuss any ambiguities or missing steps discovered

5. Introduction to Algorithm Representation (10 minutes)

   • Explain different ways to represent algorithms:
     • Natural language
     • Pseudocode (code-like language without strict syntax)
     • Flowcharts (visual representation with symbols)
   • Demonstrate how to convert a simple algorithm between representations
   • Show examples of well-written pseudocode and clear flowcharts
   • Discuss when each representation might be most useful

Closing (10 minutes)

6. Group Sharing (5 minutes)

   • Have 1-2 groups share their algorithms
   • Class provides feedback on clarity and completeness
   • Discuss challenges in creating precise algorithms

7. Exit Ticket (5 minutes)

   • Students create an algorithm for a simple task (e.g., calculating the average of three numbers)
   • Represent the algorithm using both pseudocode and a flowchart
   • Submit before leaving class

Assessment

• Formative: Quality of group algorithms and participation in discussions
• Exit Ticket: Accuracy and clarity of individual algorithm representations

Differentiation

For Advanced Students

• Create algorithms for more complex tasks
• Identify potential edge cases or exceptions in algorithms
• Compare multiple solutions to the same problem

For Struggling Students

• Provide algorithm templates or starting points
• Offer more structured tasks with clearer steps
• Use visual aids to support algorithm development

Homework/Extension

• Find an example of an algorithm used in the real world and describe it
• Create an algorithm for a morning routine or other personal process
• Research the history of algorithms and identify a significant historical algorithm

Teacher Notes

• Emphasize that algorithms are not just for computers but are a way of thinking about problem-solving
• Watch for overly vague steps in student algorithms and encourage specificity
• Make connections to how algorithms will be implemented in code in future lessons
• Consider collecting examples of student-created algorithms to use as examples/non-examples in future classes
• Remind students that the ability to represent algorithms without code is an important skill for the AP exam