📚 Year 7 OCR Computer Science: Core Knowledge Review | Year 7 OCR 计算机科学：核心知识点梳理
As students begin their journey into Computer Science, it's essential to build a solid foundation of key concepts. This article summarises the core knowledge areas for Year 7 following the OCR curriculum, including computer systems, binary, programming, algorithms, and online safety. Understanding these fundamentals will help you become confident in using technology and thinking computationally.
随着学生开始学习计算机科学，建立扎实的核心概念基础至关重要。本文总结了OCR课程Year 7的核心知识领域，包括计算机系统、二进制、编程基础、算法以及网络安全。掌握这些基础知识将帮助你在使用技术和进行计算思维时充满信心。
1. Computer Systems: Hardware and Software | 计算机系统：硬件与软件
A computer system is made up of hardware and software. Hardware refers to the physical components you can see and touch, such as the keyboard, mouse, monitor, and internal parts like the CPU and hard drive. Software is the collection of instructions or programs that tell the hardware what to do. Software can be divided into system software (e.g., the operating system that manages the computer) and application software (e.g., a web browser or word processor).
一个计算机系统由硬件和软件组成。硬件是指你可以看到和触摸到的物理组件，例如键盘、鼠标、显示器以及CPU和硬盘等内部部件。软件是指挥硬件工作的指令或程序的集合。软件可分为系统软件（例如管理计算机的操作系统）和应用软件（例如网页浏览器或文字处理软件）。
To classify hardware, we often talk about input, output, and storage devices:
为了对硬件进行分类，我们通常会提到输入设备、输出设备和存储设备：
| Type | 类型 | Function | 功能 | Examples | 例子 |
|---|---|---|
| Input Device | 输入设备 | Sends data into the computer | 将数据输入计算机 | Keyboard, mouse, microphone, touchscreen |
| Output Device | 输出设备 | Sends data out from the computer | 将数据从计算机输出 | Monitor, printer, speakers, headphones |
| Storage Device | 存储设备 | Stores data permanently or temporarily | 永久或临时存储数据 | Hard disk drive (HDD), solid-state drive (SSD), USB flash drive |
Remember that the Central Processing Unit (CPU) is the 'brain' of the computer that processes instructions. It works closely with memory (RAM) to run programs.
请记住，中央处理器（CPU）是计算机的“大脑”，负责处理指令。它与内存（RAM）密切配合来运行程序。
2. Binary: The Language of Computers | 二进制：计算机的语言
Computers do not understand numbers, letters, or pictures the way we do. They use binary, a number system made up of only two digits: 0 and 1. Each 0 or 1 is called a bit (binary digit). These bits represent the off (0) and on (1) states of the tiny switches called transistors inside a computer. Everything you see on a screen, from text to images, is stored and processed as patterns of bits.
计算机不像我们那样理解数字、字母或图片。它们使用二进制，这是一种只使用两个数字的数制：0和1。每个0或1称为一个比特（二进制位）。这些比特代表计算机内部称为晶体管的微型开关的关（0）和开（1）状态。你在屏幕上看到的一切，从文字到图像，都以比特模式存储和处理。
8 bits together form a byte. A single byte can represent 256 different values (from 00000000 to 11111111). Here is an example of converting binary to decimal (denary):
8个比特组成一个字节。一个字节可以表示256种不同的值（从00000000到11111111）。下面是一个将二进制转换为十进制（普通数字）的例子：
Binary: 1101₂ = 8 + 4 + 0 + 1 = 13 in denary
二进制：1101₂ = 8 + 4 + 0 + 1 = 13（十进制）
Each position in a binary number represents a power of 2. From right to left, the values are 2⁰ (1), 2¹ (2), 2² (4), 2³ (8), and so on. Computers use binary because it is reliable and easy to build circuits with two states.
二进制数的每一位代表2的幂。从右向左，值依次是2⁰（1）、2¹（2）、2²（4）、2³（8），依此类推。计算机使用二进制是因为它可靠，而且容易制造具有两种状态的电路。
3. Introduction to Programming Concepts | 编程概念入门
Programming is writing step-by-step instructions for a computer to follow. Almost all programs are built using three fundamental constructs: sequence, selection, and iteration. Sequence means executing instructions one after another in the order they are written. Selection means making a decision – the computer runs different code depending on a condition, often using an if/else statement. Iteration means repeating a block of code, either a set number of times (for loop) or until a condition is met (while loop).
编程是指为计算机编写一步步执行的指令。几乎所有的程序都使用三种基本结构构建：顺序、选择和循环。顺序意味着按编写顺序一条接一条地执行指令。选择意味着做出决策——计算机根据条件运行不同的代码，通常使用if/else语句。循环意味着重复执行一段代码，可以重复固定次数（for循环）或直到满足某个条件（while循环）。
Variables are another key idea. A variable is like a labelled box that stores a piece of data, such as a number or a word. The value inside a variable can change while the program runs. For example, in a game, a variable called score might start at 0 and increase when the player earns points.
变量是另一个关键概念。变量就像一个贴有标签的盒子，用来存储一段数据，比如一个数字或一个词。变量里的值可以在程序运行时改变。例如，在游戏中，一个名为分数的变量可能从0开始，当玩家得分时增加。
Many Year 7 students start coding with block-based environments like Scratch, where you drag and snap code blocks together. The same concepts of sequence, selection, and loops apply, and using variables is very common. Learning these basics now prepares you for text-based languages like Python later.
许多Year 7学生从基于积木式的环境（如Scratch）开始编程，在这些环境中你可以拖拽拼接代码块。顺序、选择和循环这些概念同样适用，使用变量也十分普遍。现在学习这些基础知识为以后学习Python等基于文本的编程语言做好准备。
4. Algorithms and Flowcharts | 算法与流程图
An algorithm is a precise, step-by-step set of instructions to solve a problem or complete a task. You follow algorithms every day – a recipe for baking a cake or instructions to build a model are both algorithms. In computing, an algorithm must be clear and unambiguous so that a machine can follow it without making guesses.
算法是解决问题或完成任务的精确、逐步的指令集。你每天都在遵循算法——烤蛋糕的食谱或搭建模型的说明都是算法。在计算机科学中，算法必须清晰明确，以便机器能够毫无歧义地执行。
Flowcharts are a visual way to represent algorithms. They use special symbols connected by arrows:
流程图是展现算法的一种可视化方式。它们使用由箭头连接的特定符号：
An oval (terminator) marks the start and end of the algorithm.
椭圆形（终止符）标记算法的开始和结束。
A rectangle represents a process or an action, like 'add two numbers'.
矩形表示一个处理或动作，如“两数相加”。
A diamond stands for a decision with a yes/no question, creating two possible paths.
菱形代表一个带有“是/否”问题的判断，产生两条可能的路径。
Arrows show the flow from one step to another.
箭头显示从一个步骤到另一个步骤的流向。
For example, an algorithm to decide whether a number is odd or even could have a start symbol, a process to read the number, a decision diamond checking if the number divided by 2 leaves a remainder of 0, and then an output to say 'even' or 'odd' before reaching the end.
例如，判断一个数字是奇数还是偶数的算法可以包含一个开始符号、一个读取数字的处理步骤、一个检查数字除以2是否余数为0的判断菱形，然后在到达结束之前输出“偶数”或“奇数”。
5. Computational Thinking Skills | 计算思维技能
Computational thinking is the thought process involved in formulating problems and their solutions so that a computer can carry them out. It is not just about coding; it is a way of thinking that helps you tackle complex problems. There are four main techniques:
计算思维是涉及将问题及其解决方案形式化，以便计算机能执行它们的思维过程。它不仅仅是编程，而是一种帮助你解决复杂问题的思考方式。主要有四种技巧：
Decomposition means breaking a large problem into smaller, more manageable parts. For example, designing a simple game could be decomposed into creating the background, programming the player movement, setting up scoring, and adding sounds. Pattern recognition involves spotting similarities or trends within the problem or with other problems you have solved before. This helps you reuse solutions. Abstraction is about focusing on the important details and ignoring irrelevant information. When drawing a map of a school, you abstract away details like the exact number of bricks and concentrate on the shape and layout of buildings. Finally, algorithm design is developing the step-by-step instructions to solve the problem, as we discussed earlier.
分解是指将一个大问题拆分成更小、更易于处理的部分。例如，设计一个简单的游戏可以分解成创建背景、编写玩家移动程序、设置计分以及添加声音。模式识别涉及在问题中或在之前解决过的类似问题中发现相似点或趋势，这有助于你复用解决方案。抽象是指专注于重要细节，忽略无关信息。在绘制学校地图时，你会抽象掉诸如具体砖块数量等细节，而专注于建筑物的形状和布局。最后，算法设计是开发解决问题的分步指令，正如我们之前讨论的那样。
6. Networking Essentials | 网络基础
A computer network is formed when two or more computers are connected together to share resources, such as files, printers, or an internet connection. Networks can be set up using wires (Ethernet cables) or wirelessly (Wi-Fi).
当两台或更多计算机连接在一起以共享资源（如文件、打印机或互联网连接）时，就形成了一个计算机网络。网络可以使用有线（以太网线缆）或无线（Wi-Fi）方式建立。
The smallest type of network is a Local Area Network (LAN). A LAN covers a small geographical area, like a home, school, or office building. In contrast, a Wide Area Network (WAN) connects computers over large distances, such as across cities or countries. The biggest WAN is the Internet itself, which is a global network of networks. It is important to distinguish between the Internet (the physical infrastructure of cables, routers, and satellites) and the World Wide Web (the collection of web pages and content accessed through web browsers using the Internet).
最小类型的网络是局域网（LAN）。LAN 覆盖一个小的地理区域，如家庭、学校或办公楼。相反，广域网（WAN）连接跨越较大距离的计算机，例如跨城市或跨国家。最大的广域网是互联网本身，它是一个覆盖全球的网络之网络。区分互联网（由电缆、路由器和卫星组成的物理基础设施）和万维网（通过网页浏览器利用互联网访问的网页和内容的集合）非常重要。
Routers are key devices that direct data packets between networks, helping information find the correct path to its destination. A switch connects devices within the same LAN and forwards data only to the intended device, which makes communication efficient.
路由器是在网络之间引导数据包的关键设备，帮助信息找到通往目的地的正确路径。交换机连接同一局域网内的设备，并仅将数据转发给目标设备，从而使通信更为高效。
7. Staying Safe Online | 网络安全
Being safe online, or e-safety, means understanding the risks of using the internet and taking steps to protect yourself. Always keep personal information private – this includes your full name, address, school, phone number, and passwords. Strong passwords should mix letters, numbers, and symbols, and should not be easy to guess (avoid using 'password123' or your pet's name).
网络安全或电子安全意味着了解使用互联网的风险并采取措施保护自己。始终将个人信息保密——这包括你的全名、地址、学校、电话号码和密码。强密码应混合使用字母、数字和符号，并且不应容易被猜到（避免使用“password123”或你宠物的名字）。
Phishing is a common scam where you receive an email or message that looks like it comes from a trusted company, but is actually an attempt to steal your passwords or bank details. Never click on suspicious links or download attachments from unknown senders. Cyberbullying is another threat – it involves using technology to harass or upset someone. If you or someone you know experiences cyberbullying, tell a trusted adult and report the behaviour on the platform.
网络钓鱼是一种常见的骗局，你会收到一封看似来自可靠公司的电子邮件或消息，但实际上是企图窃取你的密码或银行信息。切勿点击可疑链接或下载来自未知发件人的附件。网络欺凌是另一种威胁——它涉及使用技术来骚扰或使他人不安。如果你或你认识的人遭遇网络欺凌，请告诉一位可信的成年人并在相关平台上举报该行为。
Think before you post. Once something is online, it can be very difficult to remove completely. Always ask yourself: would I be comfortable if my parents or teacher saw this?
发布前请三思。一旦某些内容上网，就很难完全删除。永远问自己：如果我的父母或老师看到这个，我会感到自在吗？
8. Data Units and Storage | 数据单位与存储
All digital data, from text messages to videos, is measured in units based on bits and bytes. Understanding these units helps you know how much space files take up and why some files take longer to download than others.
所有数字数据，从短信到视频，都是用基于比特和字节的单位来度量的。理解这些单位有助于你知道文件占用多少空间，以及为什么有些文件下载起来比其他文件慢。
| Unit | 单位 | Symbol | 符号 | Size (approx.) | 大小（约） | Example | 示例 |
|---|---|---|---|
| Bit | 比特 | b | 1 single 0 or 1 | On/off state |
| Byte | 字节 | B | 8 bits | A single character, like 'A' |
| Kilobyte | 千字节 | KB | ~1,000 bytes | A short email or a page of plain text |
| Megabyte | 兆字节 | MB | ~1,000 KB | A high-resolution photo or a minute of MP3 audio |
| Gigabyte | 吉字节 | GB | ~1,000 MB | A full-length film or a game installation |
When you download a file, the time it takes depends on its size (in bits or bytes) and your internet connection speed. A larger file contains more bits, so it needs more time to be transferred. Knowing these units helps you manage storage on your devices and understand data limits.
当你下载文件时，所花费的时间取决于它的大小（以比特或字节为单位）和你的互联网连接速度。较大的文件包含更多的比特，因此需要更多的时间来传输。了解这些单位有助于你管理设备上的存储并理解数据限制。
9. Copyright and Digital Responsibility | 版权与数字责任
Most content you find online – images, music, text, and videos – is protected by copyright. Copyright gives the creator legal rights over how their work is used. It is illegal to copy, share, or use someone else's copyrighted work without permission, unless the licence allows it (for example, Creative Commons licences that let creators share work with certain conditions).
你在网上找到的大部分内容——图片、音乐、文字和视频——都受版权保护。版权赋予创作者对其作品使用方式的合法权利。未经许可复制、分享或使用他人受版权保护的作品是违法的，除非许可证允许（例如，创作共用许可证允许创作者在特定条件下分享作品）。
Plagiarism is presenting someone else's work or ideas as your own, whether you copy from a book or from a website. In school, always cite your sources when you do research. Using a search engine to find information is fine, but copying and pasting entire paragraphs without crediting the author is not.
抄袭是将他人的作品或想法当作自己的来呈现，无论你是从书上还是从网站上复制的。在学校里，当你做研究时，始终要引用你的信息来源。使用搜索引擎查找信息是可以的，但整段地复制粘贴而不注明作者是不可以的。
Being a responsible digital citizen also means considering the reliability of online information. Check the source of a website and think about whether it might be biased or contain fake news. Your actions online should be respectful, encouraging a positive digital community.
成为一个负责任的数字公民还意味着要考虑在线信息的可靠性。检查网站的来源，并思考它是否可能有偏见或包含假新闻。你在网上的行为应该尊重他人，促进积极的数字社区。
Published by TutorHao | Computer Science Revision Series | aleveler.com
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