📚 Year 9 WJEC Computer Science: Core Concepts Summary | Year 9 WJEC 计算机：核心知识点梳理
This article provides a comprehensive overview of the essential topics covered in the Year 9 WJEC Computer Science curriculum. It is designed to help students consolidate their understanding of computational thinking, programming, data representation, hardware, software, networking, and digital safety – forming a solid foundation for GCSE studies.
本文全面梳理了 Year 9 WJEC 计算机课程的核心知识点，旨在帮助学生巩固计算思维、程序设计、数据表示、硬件、软件、网络以及数字安全等关键领域，为 GCSE 阶段的学习打下扎实基础。
1. Computational Thinking | 计算思维
Computational thinking is a problem-solving approach that uses concepts central to computer science. It involves breaking down complex problems, identifying patterns, focusing on important details, and designing step-by-step solutions that can be carried out by a computer or a human.
计算思维是一种运用计算机科学核心理念解决问题的方法。它要求将复杂问题分解，识别规律，提炼关键信息，并设计出可由计算机或人执行的逐步解决方案。
The four cornerstones of computational thinking are decomposition (splitting a problem into smaller, manageable parts), pattern recognition (spotting similarities or trends), abstraction (filtering out unnecessary information to concentrate on what matters), and algorithm design (creating a clear sequence of instructions). For example, when designing a school timetable, decomposition helps separate constraints like teacher availability and room capacity; pattern recognition notices that similar subjects cluster at certain times; abstraction ignores irrelevant details such as room decoration; and algorithm design builds the scheduling logic.
计算思维的四大支柱是：分解（将问题拆分为较小的、可处理的子问题）、模式识别（发现相似性或趋势）、抽象（滤除不必要的信息，专注于关键点）和算法设计（制定清晰的指令序列）。以制作学校课表为例，分解可将教师空闲时间与教室容量分开考虑；模式识别能发现相似科目集中在特定时段；抽象可忽略教室装饰等无关细节；算法设计则构建排课逻辑。
In Year 9, students learn to apply these skills in everyday tasks and in coding projects. They practise writing algorithms for real-world scenarios, such as making a cup of tea or navigating a maze, before translating them into programming languages. This way of thinking is transferable across all STEM subjects and beyond.
在 Year 9，学生将学习在日常生活和编程项目中应用这些技能。他们练习为现实场景（如泡茶或走迷宫）编写算法，再将其转化为程序语言。这种思维方式可迁移到所有 STEM 学科乃至更广泛的领域。
2. Algorithms and Flowcharts | 算法与流程图
An algorithm is a precise set of rules or steps used to solve a problem or complete a task. Algorithms can be expressed in pseudocode, natural language, or through visual diagrams such as flowcharts. The main advantage of flowcharts is that they provide a universal, visual representation that is easy to debug and share.
算法是一组用于解决问题或完成任务的精确规则或步骤。算法可以用伪代码、自然语言或流程图等可视化图表表达。流程图的主要优势在于提供了一种通用、直观的表示方式，便于调试和分享。
Standard flowchart symbols include: an oval for Start/End, a rectangle for a process or instruction, a diamond for a decision (Yes/No), and a parallelogram for input/output. Arrows indicate the flow of control. For instance, an algorithm to decide whether to wear a coat might start with "Check temperature", use a decision diamond "Is temperature below 15°C?", then output "Wear coat" or "No coat needed" accordingly.
标准流程图符号包括：椭圆形表示开始/结束，矩形表示处理或指令，菱形表示判断（是/否），平行四边形表示输入/输出。箭头指示控制流。例如，决定是否穿外套的算法可以从"检查温度"开始，使用判断菱形"温度是否低于15°C？"，然后相应输出"穿外套"或"无需外套"。
Students are expected to interpret and create both pseudocode and flowcharts for sequence, selection (if-else), and iteration (loops). Common pitfalls include unconnected arrows or missing decision outcomes. Clear algorithms reduce errors in the final program and help build logical thinking.
学生应能解释并创建针对顺序、选择（if-else）和迭代（循环）的伪代码及流程图。常见错误包括箭头未连接或遗漏决策分支。清晰的算法能减少最终程序中的错误，并培养逻辑思维。
3. Programming Basics | 编程基础
Programming is the process of writing instructions for a computer in a language it understands. In Year 9, the focus is on mastering fundamental constructs: sequence (executing commands in order), selection (making decisions using conditions), and iteration (repeating code using loops). These are often practised with block-based environments like Scratch or text-based languages such as Python.
编程是指用计算机能够理解的语言为其编写指令的过程。Year 9 的重点是掌握基本结构：顺序（按顺序执行命令）、选择（使用条件做决策）和迭代（使用循环重复执行代码）。这些结构通常通过基于块的 Scratch 或基于文本的 Python 等语言进行练习。
ta), data types (integer, float/real, string, Boolean), arithmetic operations (+, -, *, /, %), relational operators (>, <, ==, ! gical operators (AND, OR, NOT). A simple Python example for a login check might look like:
关键编程概念包括变量（存储数据的命名内存位置）、数据类型（整型、浮点型/实数、字符串、布尔型）、算术运算（+、-、*、/、%）、关系运算符（>、<、==、!=）以及逻辑运算符（AND、OR、NOT）。一个简单的登录检查 Python 示例如下：
username = input("Enter username: ")
password = input("Enter password: ")
if username == "admin" and password == "1234":
print("Access granted")
else:
print("Access denied")
This snippet uses string comparison and logical operators. Iteration is introduced with while and for loops; a while loop continues as long as a condition is true, while a for loop repeats for each item in a sequence. For example, a countdown from 5 to 1 can use a while loop with a decrementing variable.
这段代码使用了字符串比较和逻辑运算符。迭代通过 while 和 for 循环引入；while 循环在条件为真时继续执行，for 循环则遍历序列中的每一项。例如，从5倒数到1可使用一个递减变量的 while 循环。
Commenting code with # and using meaningful variable names are also emphasised to make programs readable and maintainable. Debugging techniques, such as desk-checking and tracing values through a loop, help students identify logic errors.
使用 # 添加注释以及采用有意义的变量名同样被强调，以使程序可读且易维护。调试技术，如桌面检查和循环数值追踪，有助于学生发现逻辑错误。
4. Data Representation | 数据表示
Computers store and process all data as binary numbers – sequences of 0s and 1s. A single binary digit is called a bit, and a group of 8 bits is a byte. Understanding binary is essential because it underpins how text, images, and sound are represented digitally.
计算机将所有数据以二进制数（0和1的序列）的形式存储和处理。一个二进制位称为比特（bit），8个比特组成一个字节（byte）。理解二进制至关重要，因为它是文本、图像和声音数字表示的基础。
To convert a denary (base-10) number to binary, students use the place value table: 128, 64, 32, 16, 8, 4, 2, 1. For example, 77 in binary is found by adding 64 + 8 + 4 + 1, giving 01001101 (with leading zero to fill 8 bits). Conversion from binary to denary involves adding the place values where a 1 appears.
将十进制（基数为10）数转换为二进制时，学生使用位值表：128、64、32、16、8、4、2、1。例如，77的二进制通过 64+8+4+1 得到，即 01001101（用前导零补足8位）。二进制转十进制则需将出现1的位值相加。
Text is represented using character sets such as ASCII and Unicode. ASCII uses 7 bits, allowing 128 characters, while Unicode extends this to cover symbols from all languages and emojis. An uppercase 'A' has the binary value 01000001 (denary 65).
文本通过 ASCII 和 Unicode 等字符集表示。ASCII 使用7位，可表示128个字符，而 Unicode 扩展了范围，覆盖所有语言的符号和表情符号。大写字母 'A' 的二进制值为 01000001（十进制65）。
Images are represented as a grid of pixels, with each pixel assigned a binary number for its colour. In a simple black-and-white image, 1 might represent black and 0 white, and the image can be stored as a bitmap. Metadata, such as resolution (pixel dimensions) and colour depth (bits per pixel), determines file size and quality.
图像表示为像素网格，每个像素被赋予一个表示其颜色的二进制数。在简单的黑白图像中，1可表示黑，0表示白，图像可存储为位图。元数据，如分辨率（像素尺寸）和颜色深度（每像素位数），决定了文件的大小和质量。
Sound is captured by sampling the amplitude of a sound wave at regular intervals and converting each sample into a binary value. Key terms are sample rate (number of samples per second, in Hz) and bit depth. Higher sample rate and bit depth produce better quality but larger files.
声音通过按固定间隔对声波振幅进行采样，并将每个样本转换为二进制值来捕获。关键术语是采样率（每秒采样数，单位为Hz）和位深度。更高的采样率和位深度能带来更好的音质，但文件也更大。
5. Computer Hardware | 计算机硬件
Hardware refers to the physical components of a computer system. The central processing unit (CPU) is the brain of the computer, executing instructions fetched from memory. It consists of the control unit (CU), arithmetic logic unit (ALU), and registers. The CPU operates in a continuous fetch-decode-execute cycle.
硬件指计算机系统的物理组件。中央处理器（CPU）是计算机的大脑，负责执行从内存中获取的指令。它由控制单元（CU）、算术逻辑单元（ALU）和寄存器组成。CPU 持续运行在"取指-解码-执行"的循环过程中。
Main memory includes RAM (Random Access Memory) and ROM (Read Only Memory). RAM is volatile – its contents are lost when the power is turned off – and holds the operating system, programs, and data currently in use. ROM is non-volatile and stores the boot-up instructions (BIOS/UEFI). Storage devices such as hard disk drives (HDD), solid-state drives (SSD), and USB flash drives offer long-term data retention.
主存储器包括 RAM（随机存取存储器）和 ROM（只读存储器）。RAM 是易失性的——断电后内容丢失——并存放当前使用的操作系统、程序和数据。ROM 是非易失性的，存储启动指令（BIOS/UEFI）。硬盘（HDD）、固态硬盘（SSD）和 USB 闪存盘等存储设备提供长期数据保存。
Input devices feed data into the computer (keyboard, mouse, microphone, touchscreen), while output devices present information to the user (monitor, printer, speakers). Some devices, like a touchscreen or a network card, can act as both input and output.
输入设备将数据送入计算机（键盘、鼠标、麦克风、触摸屏），输出设备则向用户呈现信息（显示器、打印机、扬声器）。某些设备（如触摸屏或网卡）可同时作为输入和输出。
The following table summarises common hardware components and their functions:
下表总结了常见硬件组件及其功能：
| Component | Function |
|---|---|
| CPU | Processes instructions and performs calculations |
| RAM | Temporary workspace for active programs and data |
| Hard Drive (SSD/HDD) | Permanent storage for software and files |
| Motherboard | Connects all components and allows communication |
| Power Supply Unit | Converts mains electricity to voltages suitable for components |
Embedded systems are specialised computers built into larger devices (e.g., washing machines, traffic lights). They typically have a single purpose, limited resources, and run firmware stored in ROM.
嵌入式系统是集成在较大设备中的专用计算机（如洗衣机、交通灯）。它们通常功能单一、资源有限，并运行存储在 ROM 中的固件。
6. Software and Operating Systems | 软件与操作系统
Software is the collection of programs and data that tell a computer what to do. It is divided into two main categories: system software and application software. System software manages the hardware and provides a platform for running applications; the most critical system software is the operating system (OS).
软件是指示计算机如何工作的程序和数据的集合。它分为两大类：系统软件和应用软件。系统软件管理硬件并为运行应用程序提供平台；最关键的系统软件是操作系统（OS）。
Key functions of an operating system include managing the user interface (GUI or command-line), handling file management, memory management, multitasking, peripheral management, and providing security and access control. Popular operating systems include Windows, macOS, Linux, Android, and iOS.
操作系统的主要功能包括：管理用户界面（图形界面或命令行）、处理文件管理、内存管理、多任务处理、外设管理，以及提供安全与访问控制。常见的操作系统有 Windows、macOS、Linux、Android 和 iOS。
Utility software performs maintenance and optimisation tasks. Examples are antivirus programs, disk defragmenters (for HDDs), backup tools, and file compression utilities. Unlike application software, utilities often run in the background or on demand without creating user content.
工具软件执行维护和优化任务。例如防病毒程序、磁盘碎片整理工具（用于HDD）、备份工具和文件压缩工具。与应用软件不同，工具软件通常在后台运行或按需启动，而不产生用户内容。
Application software allows users to perform specific tasks: word processors, spreadsheets, web browsers, graphic editors, and games. The distinction between system and application software is a common exam topic, with emphasis on identifying the OS's role in resource allocation and abstraction of hardware complexity.
应用软件使用户能够执行特定任务：文字处理、电子表格、网页浏览器、图形编辑器和游戏。系统软件与应用软件的区别是常见考点，重点在于明确操作系统在资源分配和硬件复杂性抽象方面的作用。
Students should also understand open-source vs. proprietary software licences. Open-source software (e.g., Linux, LibreOffice) allows users to view, modify, and distribute the source code, whereas proprietary software (e.g., Microsoft Office, Adobe Photoshop) restricts access to its source code and often requires a paid licence.
学生还应了解开源与专有软件许可证的区别。开源软件（如 Linux、LibreOffice）允许用户查看、修改和分发源代码，而专有软件（如 Microsoft Office、Adobe Photoshop）限制对源代码的访问，且通常需付费许可。
7. Networks and the Internet | 网络与互联网
A network is a group of interconnected devices that can share data and resources. The main types are Local Area Networks (LANs), which cover a small geographical area like a school or home, and Wide Area Networks (WANs), which connect LANs over long distances. The internet is the largest public WAN.
网络是一组可以共享数据和资源的互联设备。主要类型有局域网（LAN），覆盖较小地理区域如学校或家庭；广域网（WAN），将远距离的局域网连接起来。互联网是最大的公共广域网。
Networks can use a client-server or peer-to-peer (P2P) model. In client-server networks, dedicated servers provide services (file storage, email, web pages) to client devices, offering centralised control and security. In P2P networks, all devices have equal status and share resources directly, which is simpler but less secure for large-scale use.
网络可采用客户端-服务器或对等（P2P）模型。在客户端-服务器网络中，专用服务器向客户端设备提供服务（文件存储、电子邮件、网页），具有集中化控制和安全性。在 P2P 网络中，所有设备地位平等，直接共享资源，更简单但大规模使用时安全性较低。
Essential networking hardware includes network interface cards (NICs), switches, routers, and transmission media (copper cable, fibre optic, or wireless signals). The router connects different networks and directs data packets using IP addresses, while a switch connects devices within the same LAN.
基本网络硬件包括网络接口卡（NIC）、交换机、路由器以及传输介质（铜缆、光纤或无线信号）。路由器连接不同网络，并使用 IP 地址引导数据包，而交换机连接同一局域网内的设备。
Protocols are agreed rules for communication. Key protocols to know: TCP/IP (the suite that governs internet traffic, ensures reliable delivery), HTTP/HTTPS (for transferring web pages; HTTPS adds encryption), FTP (file transfer), SMTP/POP3/IMAP (email sending and retrieval), and Wi-Fi (wireless networking standard IEEE 802.11).
协议是通信的约定规则。需了解的关键协议有：TCP/IP（管理互联网流量、确保可靠传输的协议族）、HTTP/HTTPS（用于传输网页；HTTPS 增加了加密）、FTP（文件传输）、SMTP/POP3/IMAP（电子邮件的发送和检索）以及 Wi-Fi（无线网络标准 IEEE 802.11）。
IP addressing (IPv4) uses four numbers between 0 and 255 separated by dots, e.g., 192.168.1.1. Domain Name System (DNS) translates human-friendly domain names into IP addresses. The concept of cloud computing – storing data and running applications on remote servers accessed via the internet – is also introduced at this level.
IP 地址（IPv4）使用由点分隔的四个0到255之间的数字，例如 192.168.1.1。域名系统（DNS）将人类易记的域名转换为 IP 地址。云计算的概念——将数据存储和应用运行在通过互联网访问的远程服务器上——也在本级引入。
8. Digital Safety and Ethics | 数字安全与伦理
As digital citizens, students must understand how to protect themselves and respect others online. Key concerns include privacy, security, cyberbullying, and the ethical use of technology. The WJEC curriculum places strong emphasis on responsible online behaviour and awareness of digital footprints.
作为数字公民，学生必须懂得如何保护自己并在线上尊重他人。关键议题包括隐私、安全、网络欺凌和技术伦理使用。WJEC 课程特别强调负责任的线上行为以及对数字足迹的认识。
Strong passwords are a first line of defence: they should be long, contain a mix of uppercase and lowercase letters, numbers, and symbols, and be unique for each service. Phishing emails attempt to trick users into revealing personal information by posing as legitimate organisations; students should learn to spot suspicious links, poor grammar, and urgent demands.
强密码是第一道防线：密码应足够长，包含大小写字母、数字和符号的混合，并且对每个服务都不同。网络钓鱼邮件试图通过伪装成合法机构来诱骗用户泄露个人信息；学生应学会识别可疑链接、语法错误和紧急要求。
Malware (malicious software) includes viruses, worms, trojans, and ransomware. Antivirus software, firewalls, and operating system updates are key protective measures. Students should also be cautious when downloading files or clicking on email attachments from unknown sources.
恶意软件包括病毒、蠕虫、特洛伊木马和勒索软件。防病毒软件、防火墙和操作系统更新是重要的防护措施。学生在下载文件或点击来自未知来源的电子邮件附件时也需保持警惕。
Privacy settings on social media and messaging apps determine who can see posts and personal information. The concept of a digital footprint means that actions online – comments, photos, likes – can be permanent and searchable. Cyberbullying involves using technology to harass or harm others, and it is important to report such behaviour to trusted adults or platforms.
社交媒体和通讯应用的隐私设置决定了谁可以查看帖子与个人信息。数字足迹的概念意味着线上行为——评论、照片、点赞——可能永久存在并可被搜索。网络欺凌指利用技术骚扰或伤害他人，遇到此类行为应及时向信任的成人或平台举报。
Ethical considerations include respecting intellectual property (copyright and fair use), avoiding plagiarism, and understanding the impact of screen time on health. Open-source licensing and Creative Commons enable legal sharing of digital content. Students learn to evaluate online information critically, checking sources for reliability and bias.
伦理考量包括尊重知识产权（版权与合理使用）、避免抄袭，以及理解屏幕时间对健康的影响。开源许可和知识共享协议使数字内容的合法分享成为可能。学生要学会批判性地评估线上信息，检查来源的可靠性与偏见。
Finally, the environmental impact of technology is discussed, including energy consumption of data centres and e-waste from discarded devices. Simple actions like recycling old hardware and supporting sustainable tech choices are encouraged.
最后，还探讨了技术对环境的影响，包括数据中心的能耗和废弃设备的电子垃圾。鼓励采取回收旧硬件和支持可持续技术选择等简单行动。
Published by TutorHao | Computer Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图