China 八年级（初二） Information Technology
Chapters: 3
1. Module: IoT practice and exploration
Features and applications of the Internet of Things · Sensors and data collection · Networked control and feedback · Building a simple IoT system · IoT security and privacy
- Internet of Things (IoT) – The Internet of Things (IoT) is a network of everyday objects that have sensors, a small computer and a network connection, so they can collect data, share it over the internet and act on it. A sensor turns a physical change into data, a microcontroller processes it, the network (Wi-Fi, Bluetooth, Zigbee, 4G/5G, LoRa) carries it to a cloud server or app, and an actuator turns commands into action. IoT is described in three layers: perception, network and application. It brings convenience and saves energy, but needs strong privacy and security.
- Sensors: How Machines Sense the World – A sensor turns a physical quantity (light, temperature, distance, moisture, sound, pressure) into an electrical signal. Analogue sensors give a smooth voltage; an ADC turns it into a number the computer can use. A controller compares the number with a threshold and switches an actuator, often through a relay. Readings taken at regular times are data logging. Good sensors have the right range, sensitivity, accuracy and response time.
- Control Systems and Feedback – A control system makes a machine or process behave the way we want. Every system has input → process (controller) → output. In an open-loop system the controller does not check the result (a toaster on a timer). In a closed-loop system a sensor measures the output and feeds it back; the controller compares it with the set point and corrects the error (a thermostat, cruise control). Real systems are built from sensors, a controller (electronic circuit, microcontroller or PLC) and actuators (motors, heaters, valves, pneumatic cylinders). Many are now networked (IoT, SCADA) so they can be watched and controlled from far away.
- Cybersecurity: Threats and How We Stop Them – Cybersecurity protects computers, networks and data. It aims for confidentiality, integrity and availability (the CIA triad). Common threats are malware, phishing and social engineering, brute-force password attacks and denial of service. Defences include strong authentication, encryption, firewalls, anti-malware software, updates, access control and backups.
2. Module: Internet applications and innovation (review/extension)
Internet protocols and services · Data security and backup; passwords, encryption
- Network Protocols and the TCP/IP Model – A protocol is a set of rules that devices agree on so they can talk to each other. Networking is split into four layers (the TCP/IP model). The Application layer has protocols that apps use: HTTP and HTTPS for web pages, SMTP to send email and IMAP to read email kept on a server. The Transport layer (TCP) splits data into numbered packets, checks them and resends any that are lost. The Internet layer (IP) adds addresses and routes packets. The Link layer sends the bits over a cable (Ethernet) or by radio (Wi-Fi). Going down the stack each layer adds a header; going up on the other side each header is removed. Layers make networks easier to build and change, because each layer only needs to talk to the layer just above and below it.
- Cybersecurity: Threats and How We Stop Them – Cybersecurity protects computers, networks and data. It aims for confidentiality, integrity and availability (the CIA triad). Common threats are malware, phishing and social engineering, brute-force password attacks and denial of service. Defences include strong authentication, encryption, firewalls, anti-malware software, updates, access control and backups.
3. Cross-disciplinary theme: Internet-smart design
Online digital weather station · Networked drone show · Introducing my school to the world
- Online Digital Weather Station – A digital weather station has sensors (temperature, wind, rain), a small board that reads them as numbers, a wifi link that sends the numbers to a cloud server, and a web page that shows them to anyone. The path is: sense, read, send, store, show.
- Networked Drone Show – A drone show is many small drones flying a drawing in the sky. A program gives each drone a list of positions (x, y, height) over time. A network lets a controller send the same start signal to all drones, so they move together. If a drone loses its link, it stops or lands safely.
- Introducing My School to the World – To introduce your school online, plan the page (name, photo, short text, menu), build it with a website tool or a media post, publish it and share the link. Share only safe things. Never share passwords, home addresses or private photos, and ask permission before showing anyone's face or name.