Students will be able to...
- Build custom blocks that take parameters.
- Do Now 3.3
- 3.3 slide deck
- Lab 3.3 - Let me check my calendar (docx) (pdf)
- parameters example
- Snap! tips: 0, 4, 8, 16
- Video resources:
- https://youtu.be/ZLxql1kLvCw
- Video quiz: See Additional Curriculum Materials accessed from the TEALS Dashboard.
- https://youtu.be/ZLxql1kLvCw
| Duration | Description |
|---|---|
| 5 minutes | Welcome, bell work, announcements |
| 15 minutes | Lecture and introduce activity |
| 20 minutes | Custom block parameter activity |
| 15 minutes | Debrief and wrap-up |
Define parameters: An parameter is any area in a block that accepts user input, or another block. It could be a Boolean Block or a value placed inside of a variable or block.
Ask students to speculate on risks of relying on variables instead of parameters.
- Variables could be changed by a script other than the custom block, variable names could be changed causing errors, etc.
- Emphasize importance of custom blocks being self-contained.
- Custom blocks should continue to function correctly independent of any other changes in the script.
- Custom blocks should work correctly anywhere in the script and not require specific setup or cleanup.
Point out how complicated a script would be if blocks like move 10 steps required setting a variable with a specific name to work.
Point out that parameters are very similar to variables, except their values come outside the block.
Explain parameter types.
- Only discuss text, numbers, and Booleans.
- Other types can be mentioned, but won't be used in the course.
Ask students to describe why restricting types is important.
- Point out that parameters are passed by value.
- Specifically, changing the value of an parameter inside a custom block will typically not change the value at the call site.
- Basic parameter in pen pallette.
- Pass by value example in "Variables" pallette.
Students should complete the Let Me Check My Calendar activity individually or in pairs.
This lab consists of a series of independent custom blocks. The blocks need not necessarily be completed in the order given, but are roughly in order of difficulty.
- The bonus requires implementing a fairly complex formula.
Ask a different student to provide their solution to each part. If time allows, discuss multiple solutions to each part. Emphasize differences and encourage discussion about advantages and disadvantages.
Point out corner cases and cases where typed parameters are particularly helpful.
- For example, avoiding try to find out whether "bubblegum" is a leap year.
Part 3.4 is a fairly complex formula and should be a challenge for advanced students.
Struggling students should focus on section 1. The problems in section 2 represent more complex algorithms, but not necessarily any more difficult usage of parameters.