National Year 9 Computing
Chapters: 3
1. Computer science
Computational thinking · Algorithms · Programming · Boolean logic and binary · Computer systems
- Searching and Sorting Algorithms – A searching algorithm finds an item in a list; a sorting algorithm puts a list in order. Linear search checks items one by one and works on any list. Binary search halves a sorted list each time and is much faster. Bubble sort swaps neighbours pass by pass; merge sort splits the list and merges sorted halves, which is faster for big lists.
- Programming Basics: Sequence, Selection, Loops and Functions – A program is a set of exact instructions a computer follows. Every program is built from three structures: sequence (steps in order), selection (if/else choices) and iteration (loops). Variables store values. Functions group code into reusable, named blocks, which makes programs modular and easier to test, debug and maintain.
- Number Systems and Encoding – A number system is a way to write numbers using a set of digits and a base. Decimal (base 10) uses 0–9, binary (base 2) uses 0 and 1, octal (base 8) uses 0–7, and hexadecimal (base 16) uses 0–9 and A–F. To go from decimal to any base, divide repeatedly by the base and read remainders bottom to top; for fractions, multiply by the base and read the integer parts top to bottom. To go to decimal, multiply each digit by its place value and add. Binary ↔ octal uses groups of 3 bits, binary ↔ hex groups of 4. Text is stored with encoding schemes: ASCII (7-bit, 128 characters), ISCII (8-bit, Indian scripts) and Unicode (every script), stored as UTF-8 (1–4 bytes) or UTF-32 (4 bytes).
- Computing Systems: From Apps Down to Logic Gates – A computing system takes input, processes it, gives output and stores data. Hardware is the physical parts; software is the instructions. Systems are built in layers of abstraction: apps on top, the operating system in the middle, hardware at the bottom, and logic gates inside the hardware. Each layer hides its details from the one above. The operating system manages memory, shares CPU time, organises files, controls devices through drivers and keeps the system secure. Logic gates (AND, OR, NOT and others) turn 1s and 0s into decisions. Good devices are designed for usability, and good users troubleshoot systematically: describe, check simple things, change one thing at a time, test, and record.
2. Information technology
Creative digital projects · Digital content
- ICT Basics: Using Computers, the Cloud and Learning Platforms Safely – ICT means information and communication technology: the devices, software and networks we use to create, store and share information. Every computer takes input, processes it, gives output and stores data. Storage is measured in bytes, and each bigger unit (KB, MB, GB, TB) is about 1000 times the one before. Good digital learners keep files in clearly named folders, use learning platforms to get and submit work, store files in the cloud and on devices, back up with the 3-2-1 rule and protect accounts with long passphrases and two-step login. ICT also lets you make creative projects such as videos, websites and podcasts.
- Media Literacy – Media literacy is the skill of reading, questioning and creating media: news, ads, videos, posts, films and games. Every media text is made by someone, for a purpose, for an audience, using forms, conventions and techniques that shape how we feel. A media-literate person checks the source, evidence, other coverage and the original before believing or sharing, notices bias and filter bubbles, and makes their own media responsibly.
3. Digital literacy
Safe and responsible use
- Digital Footprints and Netiquette – A digital footprint is the trail of data we leave online. Active footprints are shared on purpose (posts, comments, forms); passive footprints are collected without us noticing (cookies, browsing history, location, IP address). Footprints are hard to erase and can be seen by others later. We live in a digital society where learning, banking, shopping and government services are online; a responsible user of it is a digital citizen (netizen). Net etiquette means being ethical (respect copyright, share reliable information), respectful (privacy, diversity, no bullying) and responsible (avoid oversharing, don't feed trolls). Communication etiquette asks us to be precise, polite and credible; social media etiquette asks us to choose passwords and privacy settings wisely, think before uploading, and verify before sharing.