Students will be able to...
- Build custom command blocks in SNAP
- Utilize detail removal and generalization to construct blocks that practice abstraction
- Do Now 3.2: Drawing Squares
- Lab 3.2 handout - Drawing Shapes Again (Download in Word) (Link to PDF)
| Duration | Description |
|---|---|
| 5 minutes | Welcome, attendance, bell work, announcements |
| 10 minutes | Lecture, demo, and introduce activity |
| 20 minutes | Drawing Shapes activity |
| 15 minutes | Review and wrap-up |
- Lecture and Demonstration
- Review with students the concepts of abstraction, generalization, and detail removal
- Ask students to provide definitions and examples of each
- Discuss when abstraction can be used to help simplify code
- Guide students to realization that much code is used in many similar circumstances and shouldn’t be rewritten
- Emphasize potential for errors when changes are made in addition to inconvenience when code is redundant
- Demonstrate constructing a custom command block
- Use a simple example, such as jumping (from the platform game)
- If needed, use part 2.1 (drawing a square) as a further example
- Review with students the concepts of abstraction, generalization, and detail removal
- Activity
- Students should complete the “Drawing Shapes (Again)” activity individually or in pairs
- Work with students to be certain that they are using custom blocks and variables as described by the activity
- Point out places where code can be abstracted and generalized
- Emphasize conciseness and clarity in code
- Students should complete the “Drawing Shapes (Again)” activity individually or in pairs
- Review
- Discuss one or two student submissions
- Point out differences between different students’ solutions
- Point out missed opportunities for abstraction (if any)
- Discuss how this custom block can be useful
- Discuss one or two student submissions
##BJC Lecture Suggestion ####Good for Classroom Instruction
- MIT Scratch --> BYOB Snap (Development of SNAP, Demo) 10:00-11:30
- BYOB-Custom Blocks (Explains functions with examples) 11:30-14:50
- In addition to attempting the bonus in the lab, advanced students can be encouraged to write a new custom block that draws a specified number of the given shape (for example, 2 squares or 5 hexagons). The number of shapes should be taken as user input.
- Struggling students can be given solution code for all of section 1. Work with these students to answer the questions in part 1.5 so that they are prepared to attempt the custom block authoring.