Teach Computing

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

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Examples of Local Cryptocurrencies

Digital Money for Local Communities covers three examples of country-wide c...

Hash function A hash function takes arbitrary sized input data (e.g. a fil...

Cryptocurrencies vs regular currencies

What is Bitcoin and How Does it Work? is a high level overview of the Bitco...

Examples of Cryptocurrencies

Bitcoin is by far the most well known cryptocurrency. The Bitcoin website w...

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...

Resources discount offer

1.2 System Design Basics

Interestingly (strangely?) the IB Computer Science subject guide doesn't make any mention of System Development Life Cycle (SDLC), but it does include components of each major step. These are spread between this section (1.1 Systems in Organisations) and 1.2 (System Design Basics). This section covers issues which are more user-oriented and related to the actual implementation of IT systems.

Click here for recommended IB Computer Science textbooks.

Components of a computer system

1.2.2 Roles within a networked world

Internet protocols

What Happens When You Click a Link?

This video explains step by step what happens when you enter a URL in your web browser. It covers looking up the IP address using the HOSTS file or DNS, connecting to the destination machine using TCP/IP, and using HTTP to fetch the page. It does a good job of breaking down the process into a series of simple steps that demystify this process for students (hopefully!).

Updated: 2015-05-02
How DNS works

How the DNS works

An animation showing how DNS works when you type the URL of a website into your web browser. This video goes into more detail than some of the others here, showing how a computer locates nameservers before finding the IP address of a domain name. Useful for older students.

Updated: 2015-06-03
DNS Explained

DNS Explained

This video goes into a LOT of detail about DNS and the different types of nameservers: the root nameservers, the TLD nameservers, and authoriative name servers. This is probably more detail than most students will need, but it can help understand the bigger picture, so is included here.

Updated: 2015-06-03

1.2.4 Planning a new system


Software Development Lifecycle in 9 minutes!

This is quite an entertaining overview of the SDLC, with clear examples of what happens at each stage. Note that the stages in the SDLC are broken down in different ways by different people (for example, here they count planning and analysis as two separate stages - often they are incorporated into one). However, the content is sound and highlights the need for clear boundaries between the tasks in each stage.

Updated: 2019-03-14

1.2.12 - 1.2.15 Usability and Accessibility

Human Computer Interaction (HCI)

Human Computer Interaction (HCI)

This page has very detailed notes on many human-computer interaction and usability issues. It has excellent interactive examples of bad user interfaces and the mistakes that software and hardware developers often make, including information about mode errors, user feedback, consistency, and error prevention. It also has links to further reading about HCI theory and design rules.

Updated: 2015-04-18
Psychology of Computing

Psychology of Computing

This video examines the issue of computer usability. It is full of great examples of user interface design, and explains the reasons behind them. Many of the items mentioned in the video are so common that we barely notice them in our daily lives, but the video links these choices to human psychology and our understanding of the real world.

Updated: 2017-12-15

1.2.16 Moral, ethical, social, economic, and environmental implications

NSA Internet surveillance

NSA Internet surveillance

In June 2013, the Guardian and Washington Post newspapers published revelations about a secret, quasi-legal US government Internet surveillance programme known as PRISM and operated by the National Security Agency (NSA). In the following weeks global media continued publishing revelations of ever more extraordinary surveillance systems. First, revelations that the NSA had worked with the British intelligency agency GCHQ to side-step legal issues, then evidence that online images were being collected and mined, and finally, confirmation that thousands of mobile phones had been monitored and tracked. Foreign allies were quickly alienated as it was revealed that the NSA had spied on supposedly friendly governments and ministers, including the Germans, Chileans, and Brazilians. The articles below highlight some of the key events in the scandal, and make excellent material for classroom discussion of the ethics of surveillance.

Updated: 2015-05-06
Enemy of the State DVD

Enemy of the State DVD

Amazon.com | Amazon.co.uk | Instant Video

Many of the surveillance technologies and methods featured in Enemy of the State - which features Will Smith as a lawyer tracked down by government agents - may seem pure fantasy. However, recent revelations about NSA spying once again make this a relevant and pertinent film that deals with contemporary issues.

Updated: 2015-05-06
United States of Secrets PBS documentary

United States of Secrets

A compelling two-part PBS documentary about the US government (and particularly the NSA's) warrantless surveillance of the Internet of millions, which was only revealed after Edward Snowden leaked classified information

The documentary does a good job of addressing both sides of the surveillance argument, featuring interviews with government insiders, including those who were the architects of the now infamous surveillance systems.

Watch the documentary on the PBS website

Updated: 2015-05-06
Ethics in Computing

Ethics in Computing

Ethics in Computing covers a wide range of ethical situations from intellectual property to free speech and privacy. Different areas are covered - including government, medical, and educational. Each section is subdivided and has a plethora of links to case studies or news articles. This means some work is needed to find the most relevant articles, and the site itself is probably better suited to older students.

Updated: 2015-05-07