**Course Title:** Introduction to Programming with Scratch **Section Title:** Events and Message Broadcasting **Topic:** Creating interactions between multiple sprites using events. In the previous topic, we explored the basics of events in Scratch and how to use them to trigger actions when certain conditions are met. In this topic, we will take a step further by creating interactions between multiple sprites using events. **Learning Objectives:** * Understand how to use events to interact between multiple sprites * Learn how to use the "when I receive" event block to create interactions between sprites * Create a project that demonstrates interactions between multiple sprites using events **Creating Interactions between Multiple Sprites using Events** In Scratch, you can create interactions between multiple sprites using events. Events allow you to trigger actions when certain conditions are met, such as when a sprite is clicked or when a key is pressed. By using events, you can create complex interactions between multiple sprites that can enhance the user experience of your project. **Using the "When I Receive" Event Block** The "when I receive" event block is a powerful tool that allows you to create interactions between sprites. This block allows you to specify a message that a sprite will receive, and when the sprite receives that message, it will trigger a specific action. Here's an example of how you can use the "when I receive" event block to create an interaction between two sprites: 1. Create a new project in Scratch and add two sprites to the stage. 2. Create a script for the first sprite that sends a message to the second sprite when the space key is pressed. 3. Create a script for the second sprite that receives the message and performs an action when the message is received. The script for the first sprite would look like this: ``` when space key pressed broadcast [message] ``` The script for the second sprite would look like this: ``` when I receive [message] do something ``` In this example, when the space key is pressed, the first sprite sends a message to the second sprite. When the second sprite receives the message, it performs an action. **Creating a Project that Demonstrates Interactions between Multiple Sprites** Now, let's create a project that demonstrates interactions between multiple sprites using events. For this project, we will create a simple game where a player sprite interacts with a target sprite. **Project: Target Practice** In this project, the player sprite will fire a projectile at the target sprite. When the projectile hits the target sprite, the target sprite will change color and play a sound. Here's how you can create this project: 1. Create a new project in Scratch and add a player sprite and a target sprite to the stage. 2. Create a script for the player sprite that fires a projectile when the space key is pressed. 3. Create a script for the projectile sprite that checks if it has hit the target sprite. If it has hit the target sprite, the projectile sprite will send a message to the target sprite. 4. Create a script for the target sprite that receives the message and changes color and plays a sound. The script for the player sprite would look like this: ``` when space key pressed create clone of [projectile sprite] ``` The script for the projectile sprite would look like this: ``` when I start as a clone forever if touching [target sprite] broadcast [message] delete this clone ``` The script for the target sprite would look like this: ``` when I receive [message] change color by [amount] play sound [sound] ``` **Conclusion** In this topic, we explored how to create interactions between multiple sprites using events in Scratch. We learned how to use the "when I receive" event block to create interactions between sprites and created a project that demonstrates interactions between multiple sprites. **What's Next?** In the next topic, we will explore how to use broadcasting messages between sprites to create more complex interactions. **Leave a Comment/Ask for Help:** If you have any questions or need help with this topic, please leave a comment below. No discussion boards are available for this course. **External Resources:** * Scratch Documentation: [Using Events in Scratch](https://en.scratch-wiki.info/wiki/Events_Block) Note: Please make sure to check the Scratch documentation for the most up-to-date information on using events in Scratch. **Additional Resources:** * [Scratch Tutorials on YouTube](https://www.youtube.com/scratchteam) * [Scratch Forum](https://scratch.mit.edu/discuss/)