ICT · Information Processing and Presentation (K16)
Information Processing
How computers turn data into useful information, how to find what you need on the Internet, and how to browse the Web safely. Click a card, or press → to go through the lesson in order.
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Data and information
Data are raw facts, numbers or symbols. Information is data which has been given specific meaning.
information = data + meaning (labels, context, processing)
- On its own, 34 tells you nothing. Is it a mark, a temperature or a bus route?
- Add a label, a unit and a context, and the data starts to mean something.
- Processing it (sorting, comparing, averaging) turns it into information people can act on.
- The information from one process can become the data for the next, e.g. a weather forecast fed into a travel app.
Did you know?A computer only stores data, as 0s and 1s. The meaning comes from the program and from the person who reads the result.
From data to informationClick the steps in order
Data
Information
Data or information?Class votes, then click
Data processing follows rules
Data processing is the transformation of data by means of a set of predefined rules. Same input and same rules give the same output, every time.
INPUT → PROCESS (rules) → OUTPUT
- Input: the data collected, e.g. test marks typed in by the teacher.
- Process: rules decide what happens, e.g. if mark ≥ 50 then "Pass".
- Output: the result, e.g. a report slip.
- The computer does not "think". It follows the rules exactly, so the rules must be right. Change a rule and the output changes.
Everyday exampleAn MTR gate: input = your card and its balance; rule = if the balance is enough, deduct the fare; output = the gate opens and shows the new balance.
Mark processorChange the rule, then run it again
Input
→
Process: rules
→
Output
How computers process data
Computers process data by performing calculation, searching, sorting, deleting, inserting and updating.
| Operation | What it does | Example |
|---|---|---|
| Calculation | Work out new values | Class average |
| Searching | Find records that match | Find "Wong" |
| Sorting | Put records in order | Highest mark first |
| Deleting | Remove a record | A student leaves |
| Inserting | Add a new record | A new student joins |
| Updating | Change an existing value | Correct a mark after re-marking |
Did you know?A search engine, a spreadsheet and a bank all use these same few operations, just on millions of records per second.
Class 2A recordsClick a row to select it
Calculate
Search
Sort
Insert
Update selected
Delete selected
Garbage in, garbage out
The correctness of data is essential in data processing. If the input is wrong, the output is wrong, even when the rules are perfect.
wrong data→correct rules→wrong output
- GIGO stands for "garbage in, garbage out".
- A computer cannot tell that 27 should have been 72. It just processes what it is given.
- Common causes: typing slips, missing data, the same record entered twice, wrong units, out-of-date data.
- Wrong output leads to wrong decisions: the wrong student gets the prize, or a student who needs help is missed.
Real caseIn 1999 NASA lost the Mars Climate Orbiter. One team's software gave results in imperial units, while another team expected metric units. The calculations were right, but the data was wrong.
Break the dataTick an error and watch the output
Stop garbage at the door
Validation checks that data is sensible before it is accepted. Verification checks that data was copied or typed correctly.
| Check | Rule | Stops |
|---|---|---|
| Presence | Must not be blank | Missing data |
| Range | Between a minimum and maximum | Mark 880 |
| Format | Fixed pattern, e.g. 8 digits | Phone 9123-45 |
| Check digit | Last digit calculated from the others | Swapped or wrong digits |
| Double entry | Type it twice; both must match | Typing slips |
LimitValidation only proves data is reasonable, not that it is correct. An age of 14 passes a range check even if the student is really 13.
New student formTry to sneak bad data in
Form status
Output should be useful information
The same data can be output in many ways. The best output answers the user's question clearly.
- Accurate: comes from correct data (remember GIGO).
- Relevant: answers the question being asked, and nothing extra.
- Timely: ready when it is needed.
- Complete: nothing important missing.
- Easy to understand: sorted, summarised or drawn as a chart for the reader.
ThinkA list of 1,000 numbers is data. "Five students need help in fractions" is information a teacher can use tomorrow.
Who is asking?Pick a user, then an output
Information processing tools
Different software tools are designed for different processing jobs. Choosing the right tool saves time and avoids mistakes.
| Tool | Best at | Example |
|---|---|---|
| Spreadsheet | Calculating, sorting, charts | Class marks, budgets |
| Database | Storing and searching many records | School library loans |
| Word processor | Writing and formatting documents | Letters, reports |
| Presentation software | Presenting to an audience | Project presentation |
| Search engine | Finding information on the Web | Research for a project |
| Online form | Collecting data from many people | Class survey |
| Cloud storage | Storing and sharing files | Group project folder |
Pick the best toolVote, then click
Quick quiz: data and information
How a search engine works
A search engine does not search the whole Internet when you press Enter. It searches its own index, built in advance.
- 1 Crawl: programs called crawlers (or spiders) follow links from page to page.
- 2 Index: record which words appear on which pages, like the index at the back of a book.
- 3 Rank: look up your keywords in the index and order the matching pages by relevance.
So what?Each engine has its own index and its own ranking rules, so different search engines give different results. A page missing from the index cannot be found at all.
Build a tiny search engineCrawl first, then search
Different search engines for different purposes
A general search engine is not always the best tool. Match the search engine to what you are looking for.
| Type | Good for | Examples |
|---|---|---|
| General | Most everyday questions | Google, Bing, Yahoo! |
| Privacy-focused | Searching without being tracked | DuckDuckGo |
| Image / reverse image | Pictures; where a photo came from | Google Images, Bing Visual Search, TinEye |
| Video | How-to videos, lectures | YouTube |
| Academic | Research papers, books | Google Scholar |
| Maps | Places, routes, opening hours | Google Maps |
| Library catalogue | Books you can borrow | Hong Kong Public Libraries |
| Site search | Official facts on one website | GovHK, Hong Kong Observatory |
Which search engine?Vote, then click
Searching for specific information
Choose a few specific keywords, then use search operators to narrow the results down.
| Type this | Meaning |
|---|---|
typhoon signal | Pages with both words |
"signal no. 10" | This exact phrase |
typhoon -band | Exclude pages with "band" |
typhoon OR rainstorm | Either word |
site:gov.hk | Only this website or domain |
filetype:pdf | Only this file type |
intitle:typhoon | Word must be in the page title |
TipsUse nouns, not whole sentences. Start broad, then add one keyword or operator at a time. If you get too few results, remove one.
Practice search enginePick a challenge
Advanced search features
Most search engines have an Advanced Search page and a Tools menu. They fill in the operators for you and add filters such as date.
- Each box on the form matches an operator you met on the last slide.
- Date filters (past year, custom range) help when you need recent information.
- Other filters: language, region, file type, usage rights (images you are allowed to reuse).
- Refine step by step: look at the results, then tighten one filter at a time.
Where to find itLook for "Tools", "Settings → Advanced search" or a funnel icon under the search box. The words differ between search engines, but the features are the same.
Advanced search formFill a box and watch the query
Same as typing:
Is it reliable? Check before you use it
Anyone can publish on the Web. Before you download or quote something, run five quick checks.
- Who wrote it? An expert, an organisation, or an anonymous user?
- When was it updated? Is it recent enough for your topic?
- Why does it exist? To inform, to sell, or to entertain?
- Evidence: does it give sources? Do two other reliable sites agree?
- Relevant: does it actually answer your question?
Link to GIGOUnreliable sources are garbage in. Your project is the output.
Source checkerTick the checks it passes
Downloading useful information
Downloading copies a file from the Internet to your device. Download from the right place, keep it organised, and respect copyright.
- Download from the original or official source, not a copy on an unknown site.
- Check the file type and size first. Documents (.pdf, .docx) and images (.jpg, .png) are normal; programs (.exe, .apk) from unknown sites are dangerous.
- Beware of double extensions like
notes.pdf.exe: it is really a program. - Save with a meaningful file name in the right folder, and record the web address and date so you can cite it.
- Respect copyright: check the licence (e.g. Creative Commons), credit the author, and never share pirated films, music or software.
Download it or not?Look at the file name and source
Quick quiz: searching the Web
The need for safe web browsing
Most websites are fine, but some are built to trick you, steal your data or infect your device.
- Malware: viruses, spyware and ransomware hidden in downloads.
- Phishing: fake websites or messages that copy real ones to steal passwords.
- Scams: fake prizes, fake shops, fake virus warnings.
- Privacy leaks: personal data (name, HKID, address, photos) collected and misused.
- Harmful or false content: violence, gambling, fake news.
RememberScammers rely on you being in a hurry. Slow down when a page says "now", "free" or "urgent".
Spot the dangers
Super Racing 3000: free full game
Read the web address before you trust it
The address bar tells you which website you are really on. Fake sites often use addresses that look almost right.
- https:// and a padlock mean the connection is encrypted. They do not prove the site is honest: scam sites use https too.
- The real domain is the part just before the first single "/". Read it from right to left.
- Watch for look-alikes: paypa1 (number 1), rn for m, extra words, or a real name used as a sub-domain.
- Hover over a link to see where it really goes. For banks and accounts, type the address yourself or use a bookmark.
Web address checkerTry each example, or type your own
protocolsub-domain / pathreal domainignored / bad
Good practices for safe browsing
A few habits block most online dangers.
- Keep the browser, operating system and antivirus updated.
- Turn on the pop-up blocker and safe browsing protection.
- Think before you click links in messages, ads and pop-ups.
- Download only from official sources and app stores.
- Never give personal data (HKID, address, passwords) to sites you do not trust.
- Log out and close the browser on shared or public computers.
- Use strong, different passwords and two-step verification.
- If something looks wrong, stop and tell a teacher or parent.
Safe or risky?Thumbs up or down, then click
What private browsing really hides
Private (incognito) mode stops the browser saving your history and cookies on that computer. It does not make you invisible online.
- Cookies are small files a website stores in your browser to remember you (logins, settings, what you looked at).
- Private mode deletes history, cookies and form data when you close the window.
- Files you download and bookmarks you make are kept.
- The websites, the school or home network and the Internet service provider can still see what you visit.
- Useful on shared computers, so the next user cannot open your accounts.
Browser simulatorDo some browsing, then close the window
Saved on this computer
Can still see your visits
Strong passwords
Attackers use programs that try billions of guesses per second. Length matters most.
- Use 12 or more characters. A passphrase of four random words is long and easy to remember.
- Mix lower case, upper case, digits and symbols.
- Avoid common passwords and personal information (name, birthday, class).
- Use a different password for each important account, and turn on two-step verification.
- Never share your password, even with friends.
How it is estimatedPossible passwords = (characters to choose from)length. This demo assumes 10 billion guesses per second.
Password strength meterNever type a real password here
Time to crack by guessing:
Length
Character pool
Possible passwords
Quick quiz: safe browsing
Summary
Click a button to jump back to that slide.
Exit questionYour group is doing a project on typhoons. How would you search for, check and download information safely? Where could "garbage in, garbage out" happen?