Switch costumes (15+ minutes)
*5+ demonstration*
Demonstrate how to use show and hide blocks with message blocks to make it so one sprite hides in the same location as another sprite that shows to make it appear as though the sprite is changing costumes. Emphasize the importance of making sure the sprites are in the same location. For example, making them hide into a doorway, then the new sprite (costume) shows in the same location to make it appear as though the costume changed when the came back out of the door. See the video for a demonstration.

Another option demonstrated in the video involves changing costumes by switching pages to the same backdrop. Although this option works, you have to make sure every sprite is perfectly lined up to do the transition (which may require some iteration to get the timing correct if the sprite is moving). Each method can work really well depending on the project and purpose.

10+ minute application and exploration
Encourage coders to try and experiment with using one of the two methods for making a sprite appear to change costumes (it doesn’t have to relate to this project’s theme). Facilitate by walking around and asking questions about their processes.

Video: Switching costumes (3:20)

Sample questions:

• When might you switch costumes in your projects?
  • What kind of blocks might we use when switching costumes?
  • How can we hide the costume change?
    • For example, moving off the page, hiding behind another sprite, appearing to hide in a door or container, etc.

Creating a transition overlay (Advanced) (15+ minutes)
*5+ minute intro demonstration*

Demonstrate how other projects (e.g., A Day at the Beach and The Story of the Stunky Robot) use a transition overlay in the project. Use the video to learn the following process:

1. Demonstrate how to create a blank sprite that is all one color.
2. Next, demonstrate creating another blank sprite of the same color, but add your text on one side of the sprite (e.g., something like “The End” or “2 Hours Later”).
3. Use grow blocks to make the sprites as large as possible.
4. Drag the blank sprite over to one side of the screen, then drag the sprite with the text on the other side of the screen (the text should now appear centered).
5. Use show and hide blocks in an algorithm attached to either the start on green flag or start on message blocks to make both overlays show or hide.

10+ minute application and and 1-on-1 facilitating
Quickly review each of the steps for creating a transition overlay (1 - create a blank sprite; 2 - create a sprite with text; 3 - make the sprites big; 4 - position the sprites on the screen; and 5 - trigger the transitions with code). Leave your example code on the screen and give coders time to replicate the process for creating a transition overlay. Facilitate 1-on-1 as needed, but encourage coders to work together.

Facilitation suggestion: This process might be a little complicated for younger coders; however, you can group coders together in small groups to collaboratively create their own transition screen. If coders complete their stinky robot early, encourage them to begin working on their storyboard.

Advanced reverse engineering even more ideas (10+ minutes each):
*1 minute intro demonstration*

Demonstrate one of the following example sprites on the board without displaying the code (they are in order of complexity):

Page 1

• Spaceship

Page 2

• Soccer ball
• Cat
• Spaceship
• Aliencat

Page 3

• Most of the code on this page is about making sprites respond to interaction with another sprite (e.g., when tapped)
• Interaction
  • Aliencat
  • Cake
  • Cat
  • Dog
  • Globe
  • Soccer ball
• Spaceship

Page 4

• Spaceship

4+ minute reverse engineering and peer-to-peer coaching
Ask coders to see if they can figure out how to use their code blocks to create an algorithm that makes a sprite do something similar to what was demonstrated. Facilitate by walking around and asking guiding questions.

1 minute explanation demonstration
If coders figured out how to get their sprite to do something similar, have them document in their journal, share with a partner, or have a volunteer show the class their code and thought processes that led to the code. Otherwise, reveal the code, walk through each step of the algorithm, and explain any new blocks.

4+ minute application and exploration
Encourage coders to try something similar, and leave your code up on display while they work. Facilitate by walking around and asking questions about how coders might change their code so it’s not the same as yours.

Video: Suggestions for reverse engineering (4:25)

Note: It is not recommended to show each of these ideas at once, but to show one idea, give time for application and exploration, show another idea, give time for application and exploration, etc. This process could take multiple classes. Also, some of these examples may be difficult for young coders, so go slow and encourage copying and modifying code as it’s good practice.

Alternative suggestion: If reverse engineering is too difficult for the coders you work with, you could display the source code and have coders predict what will happen.

Suggested guiding questions:

• What kind of blocks do you think you might need to do something like that?
• Do you see a pattern where we might use a repeat?
• What trigger blocks do you think I used for that sprite?
• Did I use one trigger block or more than one?
  • What makes you think that?

Potential discussion:
There is not always one way to recreate something with code, so coders may come up with alternative solutions to your own code. When this occurs, it can open up an interesting discussion or journal reflection on the affordances and constraints of such code.

Suggested application and exploration questions:

• What other code blocks could you use?
• What other sprites might use similar code?

Adding even more (5+ minutes):
If time permits, encourage coders to explore what else they can create in ScratchJr. Although future lessons will explore different features and blocks, early experimentation should be encouraged.

While facilitating this process, monitor to make sure coders don’t stick with one feature for too long. In particular, coders like to edit their sprites/backgrounds by painting on them or taking photos. It may help to set a timer for creation processes outside of using blocks so coders focus their efforts on coding.

Suggested questions:

• What else can you do with ScratchJr?
• What do you think the other blocks do?
  • Can you make your sprites do ____?
• What other sprites might we use in an interactive story?
• What other sounds might we hear in your interactive story?
• Can you customize how your sprites look?