AP CSP Day 6 - Lossless Data Compression
AP CSP Day 6 - Lossless Data Compression
Course Information
- Course: AP Computer Science Principles
- Unit: Big Idea 3 - Data & Information (DAT)
- Lesson: Day 6 (50 minutes)
- Learning Objective: DAT-1.C - Explain compression techniques
Learning Objectives
Primary Goals
Students will be able to:
- Explain lossless data compression
- Identify common compression algorithms
- Apply compression techniques to data
- Analyze the impact of compression on data storage and transmission
AP Exam Alignment
- Big Idea 3: Data & Information (27-36% of AP Exam)
- Essential Knowledge: DAT-1.C.1, DAT-1.C.2, DAT-1.C.3
- Computational Thinking Practice: 2.D - Compress data using algorithms
Lesson Structure (50 minutes)
Opening Hook (10 minutes)
6.1 Welcome & Lesson Preview (5 minutes)
Teacher Activities:
- Welcome students to Day 6
- Review previous lesson's key concepts
- Introduce today's focus on lossless data compression
Student Activities:
- Review previous lesson's materials
- Think about: "What is lossless data compression?"
6.2 Quick Compression Challenge (5 minutes)
Activity: "Compress a Dataset"
Instructions:
- Groups of 4-6 students
- Compress a given dataset using lossless techniques
- Discuss the process
Purpose: Activate thinking about lossless compression
Core Content Instruction (20 minutes)
7.1 What is Lossless Data Compression? (10 minutes)
Definition (DAT-1.C.1):
Lossless data compression reduces file size without losing any information.
Key Concepts:
- **Huffman coding: Variable-length encoding
- **Run-length encoding: Replacing repeated data
- **ZIP files: Common compression format
Case Study: The compression of text in a document
- Compression process: Using Huffman coding or run-length encoding
- Outcome: A smaller file size without data loss
7.2 Common Compression Algorithms (5 minutes)
Algorithms:
- **Huffman coding: Efficient encoding
- **Run-length encoding: Simplifying repeated data
- **ZIP: Combining multiple files
Examples:
- Document editor: Text compression using Huffman coding
- Image editor: Image compression using run-length encoding
7.3 Importance of Lossless Compression (5 minutes)
Why is it important?:
- Storage: Smaller file sizes
- Transmission: Faster data transfer
- Preservation: No data loss
Discussion Questions:
- How does Huffman coding work?
- What are the benefits of run-length encoding?
- Why is lossless compression important for data preservation?
Hands-On Activity (15 minutes)
8.1 Group Project: Lossless Compression Practice (15 minutes)
Activity: "Compress and Decompress Data"
Instructions:
- Groups of 3-4 students
- Compress and decompress datasets using lossless techniques
- Discuss the process and its applications
- Present findings
Materials:
- **List of datasets to compress
- **Compression worksheet
- **Access to coding environment
Learning Goals:
- **Understand lossless compression
- **Identify compression algorithms
- **Apply compression techniques
- **Present ideas effectively
Assessment:
- **Group participation
- **Compression accuracy
- **Use of compression tools
- **Presentation clarity
Closure & Preview (5 minutes)
9.1 Key Concepts Review (2 minutes)
Today's Learning Highlights:
- ✅ Understanding lossless data compression
- ✅ Identifying compression algorithms
- ✅ Applying compression techniques
- ✅ Analyzing compression impact
AP Exam Connection:
- These concepts will appear in AP exam multiple choice questions
- Understanding compression is crucial for the Explore Performance Task
9.2 Next Class Preview (3 minutes)
Day 7 Topic: "Lossy Data Compression"
- Learning Objective: DAT-1.C - Explain compression techniques
- Activity: Practicing lossy compression techniques
- Homework: Think about a recent program you used. What compression techniques did it use? What could be improved?