Today you are coding in Scratch. You will build Shark Swim step by step at your device: a diver who swims a course, dodges a shark, and tries to reach the finish.

You can already move sprites and run a project. Today you will put movement, sensing and a win condition together into one chase game, and you will practise debugging when something does not behave as you expect.

Before you run anything, think: what do you expect to happen if the diver touches a wall or the shark?

Shark Swim has four parts:

1. A diver you swim along a course.
2. A shark that appears and moves.
3. A crash that is detected when the two meet.
4. A finish line that ends the game.

Test each part on its own before adding the next.

Create a new Scratch project and delete the cat sprite.

Scratch: How to create a new project

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Go to the Scratch website using the link below and click on the 'Create' link in the blue bar at the top.

By default, each new project starts with the cat sprite already added. To delete the cat click on the x in the blue circle beside the cat in the sprite list.

https://scratch.mit.edu

In the game a diver will swim through a course to try and reach the end without touching the edges or getting caught by the shark.

Paint a new backdrop with the following:

1. A blue background (use the square tool ).
2. A course with lanes for the diver to swim (use the paint brush tool  thickness 20). In our example we use red lines.
3. A finish line (use the paint brush tool  thickness 20). In our example we use a green line.

Scratch: How to create a backdrop

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You can create your own backdrops using the backdrop editor. To create a new backdrop put your mouse over the Choose a Backdrop button and then click on the paintbrush.

This create a blank backdrop and will open the backdrop editor where you can use the tools to create your backdrop.