Teach Computing

Revision notes, activities, lesson plans, teaching ideas, and other resources for GCSE, A-Level, and IB Computer Science teachers and students.

What's New

Practice paper 3 exam questions

One of the drawbacks of the yearly case study is that there are no past p...

Emergency Management System Explainer Video

This short video gives an overview of some EMIS features. It includes many ...

Geographic Information Systems (GIS)

For some functionality, an EMIS may also be connected to a GIS (Geographic ...

Programming languages - from Scratch to machine code

The CS Field Guide has a very comprehensive guide to different types of pro...

Assembly language simulators

There are several assembly language simulators available for use online. Si...

Little Man Computer (LMC)

The Little Man Computer (LMC) is a software simulator of a simple computer ...

Lesson - Data representation - sound

This download contains all lesson resources necessary to teach students how...

Predictive placement

Predictive placement is a feature of some CAD systems that enables more e...

AI to help emergency dispatch phone operators

The Singapore Civil Defence Force (SCDF) may trial an AI system to help tra...

Resources discount offer

C3 Distributed Approaches to the Web

These are teaching and learning resources for the IB Computer Science course C: Web science, which is an optional unit.
Click here for recommended IB Computer Science textbooks.

C.3.1 Key terms

CERN Grid Computing

CERN Grid Computing system

This brief tour of the CERN computer grid gives a good overview of the computing system and the power available.

The second video features interviews with CERN employees who explain how the grid computing system works and how the data is transmitted to and processed by multiple tiers of computers spread across Europe.

Updated: 2015-05-27

C.3.6 Lossy and Lossless compression

Image, audio, and text compression

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.

Updated: 2015-04-16
Text and image 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.

Updated: 2015-05-27
Run Length Encoding

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.

Updated: 2017-10-24
JPEG Comparison

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.

Updated: 2017-10-24

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.

Updated: 2018-02-17

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.

Updated: 2018-02-17