Grade 9 Computer Science
Three grades of computing without a word about using one safely is a gap this year closes: passwords become a counting problem, a phishing message is checked against a list rather than a feeling, and the trail you leave behind turns out to be arithmetic. Then files learn to be measured and squeezed, and programs stop holding one value at a time — lists, text, loops that run until something is true rather than a fixed number of times, and the two oldest jobs there are: finding something, and putting things in order.
Print the whole term as one worksheet pack →Using a Computer Safely
- How strong a password isLesson
Work out how many different passwords a rule allows, and use that count to say which of two rules is harder to guess your way through.
- Spotting a phishing messageLesson
Check a message against the five signs of a phishing attempt, working out for yourself whether the link in it belongs to whoever the message says it is from.
- The trail you leave onlineLesson
Work out how few harmless-looking facts it takes to narrow a crowd down to one person, and tell what a website is handed by you from what it is handed anyway.
How Much Space Data Takes
- Working out a file sizeLesson
Work out how many bytes a picture, a piece of text or a recording takes up, from how many things are in it and how many bytes one of those things needs.
- Making a file smallerLesson
Squeeze a run of repeated values into a count and a value, work out what that saves, and recognize the rows where it costs more than it saves.
Programs that Hold Many Values
- Lists and their positionsLesson
Read a value out of a list by its position, count how many values a list holds, and work out which position the last value sits at.
- Looping over a listLesson
Follow a loop that takes each value of a list in turn, and work out the total, the count or the largest value it leaves behind.
- Building a list as you goLesson
Start from an empty list and add to it inside a loop, and work out how many values end up in it and what sits at each position.
- Text inside a programLesson
Work out how many characters a piece of text holds, which character sits at a given position, and what joining two pieces of text end to end gives.
Repeating Until It Is Done
- Repeating while something is trueLesson
Follow a loop that keeps going while a condition holds, working out what it leaves behind and how many times it went round.
- Searching a listLesson
Follow a search that goes through a list from the front until it finds what it wants, and work out where it stops and how many values it had to look at.
- Putting a list in orderLesson
Take a list along once, swapping neighbors that are the wrong way round, and count the comparisons, the swaps and the passes that putting a whole list in order takes.