# Free Computing Resources

Computer Science graduate with 18 years' teaching experience and 34 years' programming experience.

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Computer Science graduate with 18 years' teaching experience and 34 years' programming experience.

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Computer Science graduate with 18 years' teaching experience and 34 years' programming experience.

TES PICKS

One of the reason that I prefer Computing to ICT is that the topics link together to form a coherent whole. My students also appear to like that aspect of the subject.
This is my first attempt at showing how the areas of the curriculum are linked, and the ideas and tasks that link topics together.
You could use the diagram in a variety of ways - e.g. if you, or members of your department are new to Computing, you can learn how different curriculum areas are linked, or you could use it for your curriculum planning by looking for routes through the topics.
In 'Visual Learning' by John Hattie, linking together the different areas of the curriculum is identified as one of the top-ten teaching techniques for 'impact'. The research also suggests that this is the main reason that teachers with greater subject knowledge are more effective, and empirical evidence suggests that it's something that teachers from a non-Computing background struggle to do.

TES PICKS

A presentation and two web-pages to explain to students how different types of information are stored as numbers inside the computer.

TES PICKS

Enter ten numbers and watch them being sorted using bubble sort, selection sort, insertion sort or quicksort algorithms, comparing the numbers of steps required for each.
The page gives a commentary on the steps taken - e.g. the numbers being compared, swapped, etc., and also describes how each algorithm works.
After learning about sorting algorithms, students could put the theory into practice by attempting the sorting balance task - see my Interactive Sorting Game task.

A collection of resources to introduce number bases to KS3 students, and binary arithmetic to older students. For younger or less able students, I would stop the presentation after the binary. Please do not use the term 'binary code' - it's just binary.
'Playing' with the binary web-page and/or the abacus allows students to quickly develop an understanding of how binary works. There is currently no worksheet for hexadecimal - I just introduce the idea. In the new Resources layout the orange button only downloads the PowerPoint presentations - look in the right-hand column for the links to the web-pages.
Notice that I don't describe octal. My intention is not to return to a 1980s-style 'computer studies' curriculum, but to enable students to understand useful computing concepts. Hexadecimal is used to describe colours; I've never used octal.
You will see from my Computing concept map (a separate resource) that binary is central to a good understanding of Computing as a whole.
UPDATE! There are now pages on binary fractions and normalising floating-point binary (but we can no longer add links as resources) - look for the links on the interactive binary page.

Presentations on truth tables and logic circuits - including operator precedence, DeMorgan's Duals, NAND, NOR and the half-adder circuit.
The truth table presentation comes first; the logic circuits one ends with the half-adder to lead you into binary arithmetic (which is in my "Number Bases - Binary and Hexadecimal" resource).
You can no longer add links to TES Resources, but further information is available on my web-site:
http://www.advanced-ict.info/interactive/boolean.html
http://www.advanced-ict.info/interactive/circuits.html
http://www.advanced-ict.info/mathematics/logic.html

I use these two presentations and the pages I've created (see links below) to introduce the idea of algorithms and efficiency.
With the algorithms presentation, the focus is very much on 'critical paths' - i.e. does it matter if you swap any of the steps around?
When discussing efficiency, I also use the following pages:
http://www.advanced-ict.info/interactive/searching.html
http://www.advanced-ict.info/interactive/algorithms.html
http://www.advanced-ict.info/interactive/sorting_balance.html
https://www.youtube.com/watch?v=o3sudomTPJA

TES PICKS

One of the reason that I prefer Computing to ICT is that the topics link together to form a coherent whole. My students also appear to like that aspect of the subject.
This is my first attempt at showing how the areas of the curriculum are linked, and the ideas and tasks that link topics together.
You could use the diagram in a variety of ways - e.g. if you, or members of your department are new to Computing, you can learn how different curriculum areas are linked, or you could use it for your curriculum planning by looking for routes through the topics.
In 'Visual Learning' by John Hattie, linking together the different areas of the curriculum is identified as one of the top-ten teaching techniques for 'impact'. The research also suggests that this is the main reason that teachers with greater subject knowledge are more effective, and empirical evidence suggests that it's something that teachers from a non-Computing background struggle to do.

A collection of resources on Boolean logic, from truth values to truth tables:
- a presentation to introduce Boolean Logic to KS3 students,
- interactive pages on Boolean operators and logic circuits
- pages on bitwise operations and a more detailed page with truth tables, masking, etc.
- a set of questions to test understanding

Resources for teaching encryption, including a PowerPoint presentation on the topic, a link to an Enigma simulator, examples of how to program encryption (in BASIC*), a page that enciphers and deciphers substitution ciphers (by shifting or using frequency analysis), and worksheets from the Bletchley Park web-site.
The KS4 version of the presentation adds VPNs for GCSE students, and the use of bitwise Exclusive-OR for encryption.
* Python examples are available at
http://www.advanced-ict.info/programming/documents/Curriculum_Python.zip

TES PICKS

An interactive comparison of linear and binary searching methods - the student thinks of a number and the computer tries to find out what it is using one of the two methods.

Help students to visualise factors, multiples, squares and prime numbers. Use the sliders to adjust the number of balls and the width of the box to demonstrate square, rectangle and prime numbers.
I came up with the idea for this page when it became clear to me that even KS4 students hadn't made the connection that a square number of things could be arranged into a square.
Updated! The balls are now scaled so that the box is never wider than the page.

TES PICKS

Enter ten numbers and watch them being sorted using bubble sort, selection sort, insertion sort or quicksort algorithms, comparing the numbers of steps required for each.
The page gives a commentary on the steps taken - e.g. the numbers being compared, swapped, etc., and also describes how each algorithm works.
After learning about sorting algorithms, students could put the theory into practice by attempting the sorting balance task - see my Interactive Sorting Game task.

A presentation to introduce students to the idea of parallel and serial transmission, and some of the simpler ways in which we can detect errors.

TES PICKS

A presentation and two web-pages to explain to students how different types of information are stored as numbers inside the computer.

This page tests students on their times tables in a visual way. They are shown an array of dots and are asked how many there are.
As the dots are displayed in a 10 x 10 grid, it can also give a sense of proportion and percentages, and students can also use number bonds to ten to work out how many rows and columns there are.
Students are scored on the number of questions they get right and the time they take, so that they can improve by getting more accurate or by answering more quickly.
Students can have multiple 'goes' at ten questions - their progress is plotted on a bar chart.

Most e-safety lessons seem to focus on issues such as the use of social media, or how to create a secure password, so I thought I'd do something a bit different. I haven't heard of this being discussed as a topic before.
I wouldn't tell the students that the lesson is about learning - I'd say that it's about the impact of technology - because I wouldn't want to affect their response to the discussion points on the second slide. You could discuss the points or get the students to write a short response before looking at the relevant articles from the news.
I would let students come to their own conclusion, but suggest that moderation might be best until the studies are conclusive.

A simple introduction to graph theory concepts for KS3 students - what networks and paths are, how to calculate the shortest path, and the relevance of this to Computing.
It would also be relevant to older students of networking, and provides a link between algorithm and network (i.e. LAN/WAN) topics.
The map and one of the questions in the on-line worksheet are actually adapted from an A level Decision Maths textbook, and questions on the shortest path have also appeared recently on GCSE Maths papers.

Link together the binary and algorithm sections of this curriculum by creating a spreadsheet (or program, if you prefer) to convert binary to decimal and vice-versa.
The presentation describes techniques that you could use for conversion both ways.
Office 2013 and LibreOffice both include the =bitand() function; if you are using an older version of Excel, then I have reproduced the =bitand() function using VBA (you will therefore need to allow the macro to run).
I can no longer add links to Resources, but you might also find the following pages useful:
http://www.advanced-ict.info/interactive/binary.html
http://www.advanced-ict.info/interactive/bitwise.html

Lots of resources on the CPU and the fetch-execute cycle are a bit light on context and detail, so I made this presentation which gives a bit of background and history, and discusses things like instruction sets in more detail than, say, the Cambridge OCR course.

An introduction to the idea of bitwise Boolean Logic (following on from my Binary and Boolean Logic lessons), which students can then use in programming of binary flags and conversion of denary to binary.
The first link is to a .zip file of programs (in BASIC - come back soon for Python versions) that use ideas from non-programming areas of the curriculum - it includes an example of using bitwise EOR to encrypt a message. The second link is to an interactive page that allows students to investigate bitwise logic. The third link is a more in-depth description for older students.
One of the things that students seem to like about the new curriculum is the way that the topics are inter-related. While bitwise logic isn't explicitly mentioned in the National Curriculum, both Boolean logic and binary are, and this is the link between the two.

Now with Python versions - look at the bottom of the web-page.
I am using Just BASIC to introduce the students to programming techniques before moving on to Visual Basic, but I see that Python is also popular in some schools, so I've also now included Python versions of the resources.
I take a concept-led approach, rather than the syntax-led approach of resources such as Codecademy - e.g. I first discuss the need for repetition before introducing the commands to do it - that way you can just change the later slides for whatever programming language you're using.
The links included in this resource are to:
- tasks for students to practise concepts and the PowerPoint presentations that I use to introduce those concepts (plus links to solutions and examples of how to program other Computing ideas).
- BASIC and Python solutions to the tasks
- a link to my BASIC and Python courses on YouTube
There are also other links on the page to programming-related topics such as compilers and interpreters, the software development life-cycle and trace tables.

See how quickly you can use a balance to sort jars into order of weight. There is a link in the presentation, or you can go directly to the page using the URL below:
http://www.advanced-ict.info/interactive/sorting_balance.html
This activity helps students to investigate sorting algorithms and is based on the CS Unplugged video:
https://www.youtube.com/watch?v=cVMKXKoGu_Y
There are brief instructions on the second slide of the presentation.
Students could attempt this activity after learning about sorting algorithms - see also my Animated Sorting Algorithms resource.

Presentations and example Scratch programs to introduce two of the ideas that students find most difficult - the idea of angles and bouncing, and the use of blocks.
There is also a link to my Scratch programming course on YouTube, which introduces a few more concepts.

An interactive diagram to help students understand the relationship between an angle and its sine or cosine and an example of how trigonometry can be used to program circular or elliptical motion.
These concepts are also important for Computing students who want to draw circles or create circular motion, and help students of Mechanics to remember whether they need to use sin() or cos() when resolving forces, etc.