Revision notes, activities, lesson plans, teaching ideas, and other resources for GCSE, A-Level, and IB Computer Science teachers and students.
UK Computing Laws
This video from Computer Science Tutor covers the main UK computing laws re...
Wireless Networking (Wi-Fi, Security, and Hardware)
This video about wireless networking includes everything that is needed for...
Network topology videos
These four excellent videos from Computer Science tutor cover the four ma...
These four videos explain the main networking protocols that students are l...
Embedded Systems video
This short video is a good over of embedded systems, covering the main poin...
Representing Text in Binary
This video clearly explains the two main ways of representing text in binar...
Types of Malware
This video explains the various types of malware including viruses and troj...
Protecting against Malware
Following on from the Types of Malware video, this video explains technique...
Video: Network Security #1
This video gives an overview of the threats to networked computer systems, ...
3.3 Data storage and Compression
3.3.2 Understand the need for data compression
A short Computerphile video which explains basic compression techniques and how they can be applied to text files and image files. The video also addresses the differences between lossy and lossless compression.
JPEG Compression comparison
A simple interactive that compares a highly compressed JPEG image with a less compressed image. A slide lets you view different parts of the image. JPEG banding is particularly visible in the sky but less so in other areas - the reasons for this make for interesting classroom discussions.
3.3.3 Understand how a lossless compression algorithm works
Image Representation - Flash activity
This Flash activity lets students draw a simple bitmap image and represents it using a simple run-length encoding (RLE) algorithm in real time. Students can also important text representations of the compressed data and the application will draw the corresponding image. The web page is not in English but the application is still perfectly usable.
Image, audio, and text compression
This very comprehensive page from the Computer Science Field Guide has extensive but clear notes on lossless and lossy compression. The page is well written and designed for a high school audience, with easy to understand examples, video, and even interactive sections. There are also extension "Extra for Experts" sections. The page covers image compression, audio compression, and text compression.
Run Length Compression (RLE) interactive
This activity shows how a computer would represent a simple image when using Run Length Compression (RLE). Students can alter the image to see how the compression data would change. This is a good resource for helping students understand how lossless compression does not always result in significant size reduction.
Compression: Crash Course Computer Science
This video explains compression techniques in the context of images. It is recommended that students have an understanding of how image data is stored (e.g. bit depths) before watching this video. The video is very comprehensive and so it may take a couple of viewings to fully understand the details of the examples being presented, but it is worth it.
Lossy and Lossless (RLE) Compression
These videos from Computer Science Tutor make great revision sources. This particular videos covers the theory behind the two types of compression - lossless and lossy.