📚 Year 7 WJEC Computer Science: Summer Preparation and Bridging Course | Year 7 WJEC 计算机：暑期预习与衔接课程
Welcome to the Year 7 WJEC Computer Science bridging course. This summer preparation resource is designed to give you a head start in understanding the fundamental concepts of computing, from computational thinking to programming and online safety. By working through these topics, you will build a solid foundation that will help you succeed in your lessons and develop digital skills for the future.
欢迎来到 Year 7 WJEC 计算机科学衔接课程。这份暑期预习资源旨在帮助你领先一步，掌握从计算思维到编程和网络安全等计算机科学的基本概念。通过学习这些主题，你将打下坚实的基础，在课堂上取得成功，并为未来培养数字技能。
1. Why Study Computer Science? | 为什么要学习计算机科学？
Computer science is far more than just using computers. It is the study of how technology works and how we can use it to solve problems creatively. In our rapidly changing digital world, understanding the principles of computing helps you become an innovator rather than just a consumer. You will learn to think logically, break down complex tasks, and design solutions that can make a real difference to people’s lives.
计算机科学远不止是使用计算机。它研究技术如何运行，以及我们如何创造性地运用技术来解决问题。在快速变化的数字世界里，理解计算原理能帮助你成为创新者，而不仅仅是消费者。你将学会有逻辑地思考，分解复杂的任务，并设计出能真正改善人们生活的解决方案。
Studying Computer Science at Year 7 provides essential skills that transfer to many other subjects and future careers. Whether you dream of becoming a games developer, a scientist, an engineer, or an entrepreneur, computational problem-solving is at the heart of modern innovation. You will also develop resilience as you learn to debug errors and test your ideas, a skill set that is highly valued by employers.
在 Year 7 学习计算机科学能培养许多可迁移到其他学科和未来职业的关键技能。无论你梦想成为游戏开发者、科学家、工程师还是企业家，计算问题解决都是现代创新的核心。在调试错误和测试想法的过程中，你也会培养坚韧的品质，这是一项深受雇主重视的技能组合。
2. Computational Thinking: The Core Skill | 计算思维：核心技能
Computational thinking is the thought process involved in formulating a problem and expressing its solution in a way that a computer (or a human) can carry out. It is the foundation of all computer science. There are four main techniques that make up computational thinking: decomposition, pattern recognition, abstraction, and algorithm design.
计算思维是将问题公式化并以计算机（或人）能执行的方式表达解决方案的思维过程。它是所有计算机科学的基础。构成计算思维的主要有四种方法：分解、模式识别、抽象和算法设计。
- Decomposition – breaking a complex problem into smaller, more manageable parts.
- Pattern recognition – identifying similarities or common patterns among problems.
- Abstraction – focusing on the important information only, ignoring irrelevant details.
- Algorithm design – developing a step-by-step solution to a problem.
下面列出这四种方法：
- 分解 – 将一个复杂问题拆分为更小、更易处理的部分。
- 模式识别 – 找出问题之间的相似之处或共同模式。
- 抽象 – 只关注重要信息，忽略无关细节。
- 算法设计 – 为问题设计逐步执行的解决方案。
For example, when planning a school trip, you would use decomposition to break the task into transport, costs, permissions, and itinerary. You might spot a pattern if the same form is needed for every trip, use abstraction to ignore students’ favourite colours, and design an algorithm (a sequence of steps) to collect all the money. These techniques will be practised throughout your course.
例如，在计划一次学校旅行时，你会用分解把任务拆分为交通、费用、许可和行程安排。你可能会发现每次旅行都需要填写相同的表格，这就是模式识别；再用抽象忽略学生们最喜欢的颜色等无关信息；最后设计一个算法（一系列步骤）来收集所有费用。你将在课程中反复练习这些技巧。
3. Understanding Algorithms | 理解算法
An algorithm is a precise set of instructions to complete a task or solve a problem. You already follow algorithms every day: a recipe to bake a cake, a set of directions to walk to a friend’s house, or the rules for a board game. In computing, algorithms must be written clearly and unambiguously so that a machine can follow them without any misunderstanding.
算法是一套精确的指令，用来完成任务或解决问题。你每天都在遵循算法：烘焙蛋糕的食谱、走去朋友家的路线说明，或是棋盘游戏的规则。在计算机科学中，算法必须写得清晰明确，没有歧义，这样机器才能毫无误解地执行。
A good algorithm has three key features: it should be correct (it produces the right result), efficient (it does not waste steps), and finite (it eventually stops). When you design algorithms, you will often represent them using pseudocode or flowcharts. For instance, an algorithm to find the largest of three numbers can be written as a series of comparisons: if the first number is greater than the second and third, it is the largest, and so on.
一个好的算法有三个关键特性：正确（产生正确结果）、高效（不浪费步骤）和有限（最终会停止）。在设计算法时，你经常会用伪代码或流程图来表示它们。例如，找出三个数中的最大值可以用一系列比较来描述：如果第一个数大于第二个和第三个，那么它就是最大的，依此类推。
4. Flowcharts: Visualising Algorithms | 流程图：算法可视化
Flowcharts use standard symbols to show the flow of control in an algorithm. They make it easier to understand how a program should work before you start coding. The main symbols you need to know are:
流程图使用标准符号来展示算法中的控制流程。这能让你在开始编程之前更容易理解程序该如何工作。你需要认识的主要符号有：
- Oval – start or end of the process
- Rectangle – a process or action, such as a calculation
- Parallelogram – input or output
- Diamond – a decision, usually a yes/no question
- Arrows – show the direction of flow
其对应中文：
- 椭圆 – 流程的开始或结束
- 矩形 – 一个过程或动作，如计算
- 平行四边形 – 输入或输出
- 菱形 – 判断，通常是一个是/否问题
- 箭头 – 表示流程方向
Consider a flowchart that decides whether a number is odd or even. After reading the number, a decision diamond asks “Is the number divisible by 2?” If yes, follow the arrow to an output parallelogram saying “Even”; if no, flow to the output “Odd”. This graphical plan can then be translated directly into code.
考虑一个判断数字是奇数还是偶数的流程图。读入数字后，一个决策菱形会问 “数字能被 2 整除吗？” 如果 “是”，就沿着箭头走向一个输出平行四边形，显示 “偶数”; 如果 “否”，则流向输出 “奇数”。这个图形化方案随后可以直接转换为代码。
5. Binary: The Language of Computers | 二进制：计算机的语言
All data inside a computer is represented using binary – a number system with only two digits: 0 and 1. These digits correspond to the off and on states of tiny switches called transistors. A single binary digit is called a bit, and a group of 8 bits is called a byte. Everything from text and images to music is stored as long strings of bits.
计算机内部的所有数据都用二进制表示——一种仅使用 0 和 1 两个数码的系统。这些数码对应着称为晶体管的微型开关的关和开状态。一个二进制位称为 比特，8 个比特组成一个 字节。从文本、图像到音乐，一切都被存储为长长的比特串。
Each bit in a binary number has a place value that doubles from right to left. The table below shows the place values for an 8-bit binary number:
二进制数中的每个位都有一个从右向左倍增的位值。下表展示了一个 8 位二进制数的位值：
| Power of 2 | 2⁷ | 2⁶ | 2⁵ | 2⁴ | 2³ | 2² | 2¹ | 2⁰ |
|---|---|---|---|---|---|---|---|---|
| Value | 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1 |
To convert binary to decimal, add the place values where a 1 appears. For example, the binary number 0010 1011 has 1s at the 32, 8, 2, and 1 places, giving 32 + 8 + 2 + 1 = 43 in decimal. Understanding binary helps you appreciate how computers store numbers, characters, and colours.
要把二进制转换为十进制，只需将所有出现 1 的位值相加。例如，二进制数 0010 1011 在 32、8、2 和 1 的位置有 1，因此等于 32 + 8 + 2 + 1 = 43（十进制）。理解二进制能帮助你认识计算机是如何存储数字、字符和颜色的。
6. Inside the Machine: Hardware Components | 机器内部：硬件组成
Hardware refers to the physical parts of a computer that you can touch. Every computer system relies on several key components working together. The table below summarises the main hardware parts and their basic functions.
硬件指的是计算机中可以触摸的物理部件。每一个计算机系统都依赖多个关键组件协同工作。下表总结了主要的硬件部分及其基本功能。
| Component | Function |
|---|---|
| CPU (Central Processing Unit) | Executes instructions and processes data; the “brain” of the computer. |
| RAM (Random Access Memory) | Temporary memory that holds data and programs currently in use. |
| Hard Drive / SSD | Long-term storage for files, software, and the operating system. |
| Motherboard | Main circuit board that connects all components together. |
| Power Supply Unit | Converts electricity from the wall outlet to power the components. |
| GPU (Graphics Processing Unit) | Handles rendering of images, video, and animations. |
中文释义：
- CPU（中央处理器） – 执行指令并处理数据，是计算机的 “大脑”。
- 内存（RAM） – 临时存储正在使用的数据和程序。
- 硬盘/固态硬盘（SSD） – 用于长期存储文件、软件和操作系统。
- 主板 – 连接所有组件的主电路板。
- 电源 – 将来自插座的电力转换为组件所需的电能。
- 图形处理器（GPU） – 处理图像、视频和动画的渲染。
Input devices such as keyboards, mice, and touchscreens let you send information to the computer. Output devices like monitors, speakers, and printers present the results to you. Hardware and software must work hand in hand to accomplish any task.
键盘、鼠标和触摸屏等输入设备让你向计算机发送信息。显示器、扬声器和打印机等输出设备则将结果呈现给你。要完成任何任务，硬件和软件必须协同工作。
7. Software: From Operating Systems to Apps | 软件：从操作系统到应用程序
Software is the set of instructions that tells the hardware what to do. It can be divided into two main categories: system software and application software. The most important system software is the operating system (OS), such as Microsoft Windows, macOS, or Linux. The OS manages hardware resources, provides a user interface, and allows other programs to run.
软件是指挥硬件运作的一系列指令。它可以分为两大类：系统软件和应用软件。最重要的系统软件是操作系统，例如 Microsoft Windows、macOS 或 Linux。操作系统管理硬件资源，提供用户界面，并允许其他程序运行。
Application software performs specific tasks for the user. Examples include word processors (like Microsoft Word), web browsers (like Chrome), games, and photo-editing tools. Apps on your tablet or smartphone are also application software. Without system software to act as a bridge, application software could not communicate with the hardware effectively.
应用软件为用户执行特定任务。例如文字处理器（如 Microsoft Word）、网页浏览器（如 Chrome）、游戏和照片编辑工具。平板电脑或智能手机上的应用程序也属于应用软件。如果没有系统软件作为桥梁，应用软件就无法有效地与硬件进行通信。
8. Storing Information: Memory and Storage | 存储信息：内存与存储
It is common to confuse memory (RAM) with permanent storage. They serve very different purposes. RAM is temporary, or volatile – when you turn off the computer, everything in RAM is lost. Storage, such as a hard disk drive (HDD) or solid-state drive (SSD), is non-volatile and keeps your files safe even when the power is off.
人们常常将内存（RAM）和永久存储相混淆。它们的功能截然不同。RAM 是临时的，即易失性的——关机后 RAM 中的所有内容都会丢失。而硬盘驱动器（HDD）或固态硬盘（SSD）这类存储则是非易失性的，即使断电，你的文件也能安全保存。
| Feature | RAM (Memory) | Storage (HDD/SSD) |
|---|---|---|
| Volatility | Volatile (data lost on power off) | Non-volatile (data retained) |
| Speed | Very fast | Slower than RAM |
| Capacity | Smaller (typically 4 GB – 32 GB) | Larger (256 GB – several TB) |
| Purpose | Holds running programs and open files | Long-term storage of files and software |
中文对照：
- 易失性：内存断电数据即丢失；存储断电仍保留数据。
- 速度：内存极快；存储比内存慢。
- 容量：内存较小（通常 4 GB – 32 GB）；存储较大（256 GB – 数 TB）。
- 用途：内存存放正在运行的程序和打开的文件；存储用于长期保存文件和软件。
Understanding this difference helps you choose the right specifications for a computer. More RAM lets you run more applications smoothly at the same time, while larger storage holds more of your games, videos, and documents permanently.
理解这一区别有助于你为计算机选择合适的配置。更大的内存能让你同时流畅运行更多应用程序，而更大的存储容量则可以永久存放更多的游戏、视频和文档。
9. Starting to Code with Scratch | 用 Scratch 开始编程
Scratch is a visual programming language developed by MIT that lets you create interactive stories, games, and animations by dragging and dropping blocks. It is an excellent starting point for beginners because you do not need to memorise complex syntax. The Scratch interface consists of a stage (where your project runs), a sprite list, and a blocks palette.
Scratch 是麻省理工学院开发的一种可视化编程语言，通过拖放积木块就能创建互动故事、游戏和动画。它对初学者来说是一个极佳的起点，因为你无需记忆复杂的语法。Scratch 的界面由舞台（项目运行的地方）、角色列表和积木块
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