You can already make sprites move and respond in Scratch. Today you will build a Paddle Ball game step by step.

Before you run anything new, think: if the ball's step size is stored in a variable called speed, what might happen when that value goes up after each hit?

You will predict, build, run, and fix as you go, and use mouse input so you can control the paddle.

Paddle Ball has four parts. You will build them in this order, and test each one before you add the next: a ball that bounces around the stage on its own; a speed value stored in a variable, so the ball can get faster later; a paddle you control with the mouse, that the ball bounces off; and a game over line that stops the game when the ball gets past you. Splitting a build into parts like this is called decomposition. It also makes bugs easier to find: when something breaks, you already know which part to look at.

Create a new Scratch project and delete the cat sprite that's added by default.

Add the sprite called 'Paddle' from the sprite library.

Drag the paddle to near the bottom of the stage area (by holding down the left mouse button and moving your mouse). Make sure to leave some space between the bottom of the stage area and the paddle (this is important later on as we'll be putting something there).

Add the sprite called 'Soccer Ball' from the sprite library.