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This add-on will be a little more challenging than the rest, because this video will only give you a few hints to help you get started.

Then, it's up to you to use your persistence and curiosity to figure out the rest.

This video will get you started with changing the background color based on what the user inputs into your program.

To get input from a user, use the ask and wait block.

Make sure to put this block in the Stage and not under any of the sprites.

Drag out the block and type some text like, "What's your favorite color?"

Scratch will save the response from the user in a variable called answer, which you can find under Sensing.

To make the background change to the color the user inputs, create some preset color backgrounds under the Backdrops section.

Try to create backgrounds for colors you think your users might want.

Computer scientists often design their projects for a specific audience and brainstorm ways to make the project ideal for that specific group of users.

Next, use a conditional block to check if the user's answer is equal to a specific value.

The code should say something like this: If the answer is equal to yellow, then switch the backdrop to yellow.

If the answer is equal to blue, then switch the backdrop to blue.

You can use several if statements to program as many backgrounds as you want.

This add-on challenges you to build code on your own, without showing you every step.

If you get stuck, you can always ask your neighbor.

Or, put your sticky up to ask your Guru.

Now it's your turn.

Use the ask and wait block to get input from a user.

Change the background color based on the user's answer.

And ask your neighbor or Guru if you get stuck.

Choose an Add-On

Party Time!

Make sprites spin and change colors.

Now You See Me...

Using "show" and "hide" make the sprites in your project appear and disappear.

Stage Lights

Change the background based on user input.

Random Appearances

Make art elements appear randomly.

Triangles All the Way Down

Create a fractal with many little triangles.


Learn how to create spirals.


  1. Choose a recipient for your card, such as a parent, friend, or teacher.
  2. Craft and code a message for that person about CS First.
  3. Create art to enhance your card and show off what you've learned.
  • "Crowd down the street" by Guillaume ( -- Licensed by CC BY 2.0 ( -- Image scaled up, cropping edges
  • "Greetingcards" by Sotakeit ( -- Licensed by Creative Commons Attribution 3.0 Unported ( -- Image scaled up, cropping edges