AP CSP Day 2 - Data Representation

Course Information

• Course: AP Computer Science Principles
• Unit: Big Idea 2 - Computer Systems and Networks (CSN)
• Lesson: Day 2 (50 minutes)
• Learning Objective: CSN-1.B - Understand data representation in computer systems

Learning Objectives

Primary Goals

Students will be able to:

1. Understand how data is represented in computer systems
2. Convert between different number systems (binary, decimal, hexadecimal)
3. Test and refine their understanding of data representation
4. Analyze real-world scenarios involving data representation

AP Exam Alignment

• Big Idea 2: Computer Systems and Networks (16-20% of AP Exam)
• Essential Knowledge: CSN-1.B.1, CSN-1.B.2, CSN-1.B.3
• Computational Thinking Practice: 2.A - Develop algorithms for solving problems

Lesson Structure (50 minutes)

Opening Hook (10 minutes)

1.1 Welcome & Lesson Preview (5 minutes)

Teacher Activities:

• Recap previous day's content on computer systems
• Introduce today's topic on data representation

Student Activities:

• Think about: "How is data represented in computers?"

1.2 Data Representation Examples Challenge (5 minutes)

Activity: "Convert Between Number Systems"
Instructions:

• Groups of 4-6 students
• Convert numbers between binary, decimal, and hexadecimal
• Discuss the importance of data representation

Purpose: Activate thinking about data representation

Core Content Instruction (20 minutes)

2.1 What is Data Representation? (10 minutes)

Definition (CSN-1.B.1):

Data representation involves encoding information in a form that can be processed by a computer.

Key Concepts:

• Binary: Base-2 number system
• Decimal: Base-10 number system
• Hexadecimal: Base-16 number system
• ASCII and Unicode: Character encoding standards

Case Study: Representing text in a computer

• Example: The letter 'A' is represented as 65 in ASCII

2.2 Common Data Representation Techniques (5 minutes)

Examples:

• Binary conversion: Decimal to binary
• Hexadecimal conversion: Binary to hexadecimal
• Character encoding: ASCII and Unicode

Discussion Questions:

1. What makes good data representation?
2. Can you think of an example where data representation is used in daily life?
3. Why is data representation important in programming?

2.3 Advanced Data Representation Concepts (5 minutes)

Why is it important?:

• Efficiency: Storing data compactly
• Interoperability: Ensuring systems can communicate

Discussion Questions:

1. How can we ensure efficiency in data representation?
2. Why is interoperability important when representing data?

Hands-On Activity (15 minutes)

3.1 Group Project: Practice Data Representation (15 minutes)

Activity: "Convert and Encode"
Instructions:

• Groups of 3-4 students
• Practice converting numbers between binary, decimal, and hexadecimal
• Encode simple messages using ASCII
• Present results to the class

Materials:

• **Conversion worksheet
• **Encoding checklist

Learning Goals:

• **Understand data representation
• **Convert between number systems
• **Encode messages using ASCII
• **Present ideas effectively

Assessment:

• **Group participation
• **Conversion accuracy
• **Encoding correctness
• **Presentation clarity

Closure & Preview (5 minutes)

4.1 Key Concepts Review (2 minutes)

Today's Learning Highlights:

1. ✅ Understanding data representation in computer systems
2. ✅ Converting between number systems
3. ✅ Encoding messages using ASCII
4. ✅ Analyzing real-world scenarios

AP Exam Connection:

• These concepts will appear in AP exam multiple choice questions
• Understanding data representation is crucial for the Explore Performance Task

4.2 Next Class Preview (3 minutes)

Day 3 Topic: "Networking Basics"

• Learning Objective: CSN-1.C - Understand networking basics
• Activity: Exploring network topologies
• Homework: Think about a recent message you sent. How was it encoded?