Lesson Plan

• Describe why data compression is essential for storage efficiency and fast transmission.
• Distinguish between lossless and lossy compression techniques.
• Calculate compression ratio and percentage space saving for a given file.
• Identify common algorithms appropriate for text, image, audio, and video data.
• Evaluate when to choose lossless versus lossy compression based on data integrity and quality requirements.

• Projector or interactive whiteboard
• Slide deck with diagrams and examples
• Handout containing a compression‑ratio worksheet
• Sample files (text document, JPEG image, MP3 audio)
• Laptop with compression tools (e.g., WinZip, Audacity)
• Calculator or spreadsheet software for calculations

Begin with the question, “How would you download a 2‑GB movie on a slow 3G connection?” Students discuss possible solutions, leading to the concept of compression. Review prior knowledge of file sizes and network speed. State that by the end of the lesson they will be able to explain why compression matters and how to measure its effectiveness.

1. Do‑Now (5'): Quick mental‑math task – estimate how long a 500 KB file would take to download at 56 kbps.
2. Mini‑lecture (10'): Define data compression, present reasons for compressing data, and introduce lossless vs. lossy.
3. Guided demonstration (15'): Show live compression of a text file (lossless) and an image (lossy); calculate ratio and space‑saving.
4. Group activity (15'): Teams work on the worksheet, calculating ratios for provided sample files and deciding which algorithm type is appropriate.
5. Check for understanding (5'): Exit‑ticket question – “When would you choose lossless over lossy compression?”
6. Summary & transition (5'): Recap key points and preview next lesson on specific compression algorithms.

Review the main reasons for compressing data and the two categories of compression. Students submit their exit‑ticket answers, demonstrating immediate recall. For homework, assign a short research task: find a real‑world example where lossless compression is mandatory and explain why.