Classes
Classes carry responsibilities. A Student class should know about a student — not about printing reports or saving files.
Python for Kids · Class 9 · Module 4 of 9
Object-Oriented Programming
Model the world as things that know something and can do something.
8 sessionsSessions 25–32
4 weeksTypical pace
Intermediate to AppliedLevel
Class 9Python & Coding
The big idea
Students design multi-class systems: what each class is responsible for, how classes relate, and when to reuse behaviour through inheritance versus building objects out of other objects.
Why it matters
Modelling a real system in objects is a thinking skill as much as a coding one. It rewards clear analysis of who is responsible for what.
Unpacked
What you will actually learn
Three core ideas, each taught with worked examples and then practised until it feels obvious.
Inheritance intuition
Inheritance expresses “is a kind of”. A PrefectStudent is a Student with extra powers, inheriting everything and adding a little.
Composition
Composition expresses “has a”. A Club has Members and a Schedule. In practice, composition solves more problems more cleanly than inheritance.
Did you know?
Experienced developers have a saying: “favour composition over inheritance.” Deep inheritance trees look elegant and become very hard to change.
Common mix-up
“Inheritance is for saving typing.” Inheritance is for expressing a genuine relationship. Using it to share code creates fragile designs.
Session by session
Your 8-session journey
Sessions 25–32 of the 72-session year, at two one-hour sessions per week.
- 1
Warm-up and big picture
Where this module fits, what you will build, and a hands-on starter that gets everyone curious about classes.
- 2
Classes
Guided teaching on classes, worked through together with the teacher.
- 3
Classes — practice lab
Independent practice, small challenges and one deliberate mistake to diagnose.
- 4
Inheritance intuition
Guided teaching on inheritance intuition, building directly on the previous two sessions.
- 5
Inheritance intuition — practice lab
Applied tasks that combine classes and inheritance intuition in one piece of work.
- 6
Composition
Composition introduced and practised, completing the toolkit needed for the project.
- 7
Project build
Guided build session for the module project: School club management model.
- 8
Test, present and reflect
Finish, test against the checklist, present the work and explain the decisions behind it.
Project lab
School club management model
Every module ends with something the student built themselves and can demonstrate. This is the piece that goes into their portfolio and gets explained out loud at the end of session 32.
Try this at home
Model your school’s club system with at least three classes, then add a brand-new club type and see how much existing code you had to touch.
It is finished when
- It works from start to finish without breaking
- You can explain every part of it in your own words
- You tested it and improved at least one thing afterwards
- Someone else used or understood it without your help
By the end of this module
Students finishing Module 4 can:
- Explain and use classes without prompting
- Explain and use inheritance intuition without prompting
- Explain and use composition without prompting
- Build and finish school club management model
- Test your own work and correct what you find
- Talk an adult through what you made and why
Word bank
The vocabulary introduced here, in plain language:
- inheritance
- A class taking on the behaviour of a parent class.
- composition
- Building an object out of other objects.
- responsibility
- The single job a class is meant to handle.
Module challenge
Think you have got this?
0 XPLevel 1 · Curious Beginner
6 quick questions drawn from this module — vocabulary, the project you build, and a myth-or-fact round. Every wrong answer explains itself, so a mistake still teaches you something.
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