SS 2 First Term

Learning Objectives

• Describe the internet and the services it provides.
• Explain how data travels across the internet.
• Describe online safety, ethics and security.
• Apply rules for safe and responsible online behaviour.

What the Internet Is

The internet is a global network of networks. It began as a research project called the ARPANET, which connected universities in the United States. Other networks joined over the years, and the result is a system with no central control and no single owner.

The internet is not the same as the World Wide Web. The internet is the network that carries data, and the web is one service running on it, made of linked pages. Email, file transfer and voice calls also run on the internet without being part of the web.

The internet and the web are not the same thing. The web is one service on the internet.

The internet has no central owner or control, so no single organisation can switch it off.

How Data Travels

Data is split into small pieces called packets. Each packet carries the addresses of the sender and the receiver and a part of the data. Packets travel along any available route and may take different routes, and they are reassembled in the correct order when they arrive.

The rules that govern this are called protocols. The main set is TCP/IP, which governs how data is addressed and routed. HTTP governs the web, SMTP governs sending mail and FTP governs file transfer.

Data travels through several media. Twisted pair copper cable carries it inside a building. Fibre optic cable carries it as light over long distances at very high speed. Radio waves carry it between buildings and to mobile phones. Satellites carry it between countries.

The amount of data a connection can carry at one time is its bandwidth. A wider bandwidth carries more data in the same period, which is why a fibre connection feels faster than a mobile connection.

Bandwidth is the amount of data that can be carried at one time, not the speed of one file alone.

Broadband means a connection that carries a large amount of data.

Phishing means a method of tricking a user into giving away details.

Services on the Internet

The services are grouped into communication, information and transaction. Communication services include email, chat, forums, social networks and video calls. Information services include the web, search engines, digital libraries and online encyclopaedias.

Transaction services include online banking, shopping, paying bills, registering for examinations and submitting tax returns. Government services in Nigeria, such as the national identification number and the tax filing platform, are reached this way.

Cloud services store files on servers rather than on the computer, so the files can be reached from any device with an internet connection. Collaboration tools allow several people to work on the same file at the same time.

A modem does not create the internet connection. It converts the signal so that the computer can use it.

Cloud storage means storage held on remote servers and reached over the internet.

Access and the Local Situation

Access is provided by an internet service provider, which sells a connection and gives an address to the subscriber. Access may be by cable, by fixed radio, by mobile data or by satellite, and the choice affects the speed, the cost and the reliability.

In Nigeria, schools and homes use a mixture of these. Many schools depend on a single connection shared by all the computers in a laboratory, so one user downloading a large file slows the work of everyone else.

A school network should be planned with the number of users in mind, because a connection adequate for five users is not adequate for thirty.

Web Technologies

The web works through addresses and browsers. An address beginning with https is encrypted, which means the data is scrambled in transit and cannot easily be read by anyone who intercepts it. A browser requests a page, the server sends it and the browser displays it.

A page that is too large takes long to load, which matters in a school where the connection is shared. Keeping pages light is therefore a practical concern as well as a technical one.

Personal Safety Online

Anything posted online can be copied and shared, and a post cannot be fully withdrawn. The rule to follow is to post nothing that would embarrass you if it appeared on a poster in school. This covers photographs, messages and reactions to other people's posts.

Personal details must be kept private. These include a home address, a phone number, a bank account, a password and the name of the school a child attends. A genuine organisation never asks for a password, so a message that does so is almost certainly an attack.

Personal safety also covers contacts. Accepting a request from a stranger gives that person access to your profile and your list of contacts. Meeting someone first met online must never happen without a parent or teacher present.

Cyber safety means the practices that protect a person and a device when online.

Personal information means details that identify a person, such as an address or a password.

Security of the Computer

A virus is a program written to damage a computer or the data on it. A worm spreads across a network by itself. A trojan looks useful but carries a harmful part. Spyware collects information without the user knowing. Ransomware locks files and demands a payment to release them.

Protection is by prevention. An up to date antivirus program checks files and removes anything harmful. A firewall blocks unwanted connections. Strong passwords of at least eight characters with a mixture of letters, numbers and symbols are much harder to guess, and a different password is used for each important account.

Software is updated because updates repair faults that attackers can use. An operating system or a browser that is no longer supported will eventually be attacked successfully, so a device that cannot be updated should be replaced rather than kept.

Cyber Crime and Cyber Ethics

Cyber crime is any crime committed using a computer or a network. Examples include accessing an account without permission, copying paid software, spreading a virus deliberately, forging a document and carrying out fraud online. Most countries, including Nigeria, have laws that make these offences punishable.

Cyber ethics is the correct use of information and communication technology. It means respecting the rights of others, respecting copyright, respecting privacy and not using technology to harm anyone.

Copyright is the right of the owner to control the use of a work. Copying a textbook, a song or an image without permission breaks copyright. Quoting a short part with the source named is acceptable. Plagiarism is presenting the work of another as one's own, whether or not copyright was involved.

Healthy and Responsible Use

Time spent online must be balanced. A fixed daily limit agreed with a parent or teacher prevents the loss of sleep and the neglect of study that heavy use causes. Sitting at a computer for hours without a break harms the eyes, the back and the wrists.

Content must be chosen with care, because material found online is not checked for accuracy or suitability by anyone. Parents and teachers should know which sites are suitable for the age group, and filtering software helps where a school can install it.

Practical Work

1. List five services of the internet and one use of each.
2. Describe what happens when a web page is requested.
3. Write five rules of safe online behaviour.
4. Explain why a strong password matters.

Scenario-Based Questions

1. A learner receives a message asking for a bank password. Explain what to do.
2. Explain why the same information may be untrustworthy even on a popular site.
3. Describe two ways to keep an account secure.
4. Explain why personal information should not be shared publicly.

LEARNING OBJECTIVES: BY THE END OF THE LESSON STUDENTS SHOULD BE ABLE TO:

Rationale: The internet is a global network of networks. Understanding what the Internet Is, how Data Travels, services on the Internet, access and the Local Situation helps learners use digital technology confidently, safely and responsibly.

Pre-requisite Knowledge: In Week 7, learners studied Computer Networks, including what is a Network Topology?, bus Topology, star Topology. The knowledge from that week is used again in this lesson.

Learning Material/Teaching Aid: Whiteboard, markers, computer or laptop where available, printed notes and charts on The Internet and Online Safety, practical task sheets, learners' notebooks and pens.

Reference Materials: Digital Technology for Senior Secondary Schools (SS 2); NERDC Digital Technology Curriculum; Digital Technology SS 2 First Term Notes (Week 8); First Term examination and Continuous Assessment question papers.

LESSON DEVELOPMENT

Assignment: i. A learner receives a message asking for a bank password. Explain what to do. ii. Explain why the same information may be untrustworthy even on a popular site.