Lesson 8: Functions and Modularity

Understand the basic concept of functions: Help students understand the definition and purpose of functions and how they can be used to achieve code reusability.
Master the basic idea of modular programming: Students will gain a preliminary understanding of the advantages of modular programming and use simple functions to organize their code.
Cultivate structured programming thinking: By breaking down tasks and encapsulating them into functions, students will enhance their logical thinking and problem-solving abilities.

Introducing the Topic: Ask students: “If you want to make a character jump and turn repeatedly, is there a way to do it without writing the same code over and over again?” This will lead to the concept of functions.
Preliminary Introduction: Explain that a function is a reusable block of code that can be “called” to execute the same set of instructions. Use analogies from daily life, such as a “recipe” or “instruction manual,” to help students understand the concept of functions.

What is a Function? (10 minutes)
- Definition of a Function: Introduce a function as a named block of code that can be called multiple times when needed, reducing code repetition.
- Purpose of a Function: Demonstrate with an example, such as a “jump” function, which allows a character to “jump” at any time in the program without having to write the same code each time.
- Function Input and Output: Briefly introduce that a function can accept input (parameters) and return a result (output), for example, controlling the height of a character’s jump by inputting a “jump height.”
Creating and Calling Functions (10 minutes)
- Demonstrating Function Creation: Show how to create a function (or use a custom code block) in a visual programming platform.
- Calling a Function: Have students try calling the functions they have defined and observe how functions help simplify their operations. For example, design a “move and jump” function combination and call it repeatedly to achieve continuous actions.
The Concept of Modular Programming (5 minutes)
- What is Modularity?: Introduce modular programming as a method of organizing a program by breaking down the code into multiple independent functions, making the code structure clearer and easier to maintain.
- Benefits of Modularity: Help students understand that modularity makes a program easier to understand and modify, especially as the program becomes more complex.

Project Description: Have students design a small project, such as a “moving and jumping game” for a character, by writing multiple functions to implement the character’s various actions.
Group Practice: Students work in groups, trying to break down complex actions into different function modules and calling these modules in their program, experiencing the benefits of modular programming.

Review of Key Points: Summarize the concepts of functions and modularity and their importance in programming.
Q&A Session: Answer students’ questions and encourage them to use functions in their own projects after class to simplify their code.

Visual Programming Platform: Such as Scratch, used to demonstrate function and modularity operations.
Sample Code: Prepare some simple function examples to help students understand how to define and call functions.

Hands-on Task: Have students design a small project in Scratch that includes at least two functions, such as a “jump and turn” mini-game.
Thinking Task: Have students think about which tasks in their daily lives can be modularized (such as the steps for cooking, exercising, etc.) and share them in the next class.