1, 2, 3, code ! - Cycle 2 activities - Séance 2b.5. Coordinating the first two episodes

Summary

Students must figure out how to make the two first episodes continue one after the other. To do this, they learn the key idea of message: a message can be sent during an instruction, and when the message is received, it can trigger one or more instructions.

Key ideas
 (see Conceptual scenario, page XX)

 

“Algorithms”

  • Instructions can start at the same time if they are triggered by the same event.

Equipment

For the class

  • (Recommended) A computer on which the Scratch software has been installed and a video projection system.

For each student pair

  • A computer on which the Scratch application has been installed.

For each student

  • Handout 32, page XX

Glossary

Script, event

Duration

45 min

 

Starting the activity

The teacher reminds the students that for the time being, the hero's program (the river episode) is deactivated (no event will trigger it). However, now we want the two story episodes to follow one after the other. This is what they will be doing today.

 

Activity (ideally in pairs)

The teacher tells the students the instructions they must use:

 

 

The teacher lets them decide on their own how to include them in their program to get the expected result.

 

Group discussion

The group discussion lets students discuss any difficulties they encountered and the solutions they found. The easiest solution is the following:

In the stage programming area, the stage is initialized for the beginning of the story:

 

 

At the end of the hero's first script (which marks the end of the river episode), add the instruction "Switch backdrop to Landscape_dock."

Trigger the hero's script for the river episode with the event "When green flag clicked."

Trigger the hero's and octopus's scripts for the dock episode using the backdrop switch event by placing the instruction "When backdrop switches to Landscape_dock" at the start of these scripts.

The initializers must also be added, namely to hide the octopus when the green flag is clicked and resizing the hero to 100%.

The file "II-2b_dock_correction_lesson_5.sb2" provides an example of the result for the first two episodes (when the river and dock episodes are connected).

 

Conclusion and lesson recap activity

The class summarizes together what they learned in this lesson:

  • Scripts are triggered by events. Within a program, a single event can trigger several scripts at once.

Students write down these conclusions in their science notebook. They then complete their Scratch worksheet by coloring in the instructions they learned during the lesson and writing down the key words: broadcasting messages, "when I receive message" event.

 


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