Skip to content

Latest commit

 

History

History
119 lines (82 loc) · 6.47 KB

lesson_23.md

File metadata and controls

119 lines (82 loc) · 6.47 KB

Lesson 2.3: Inputs and Conditionals

Student Objectives

Students will be able to...

  • Ask for and receive user input in a SNAP program
  • Use simple conditional (if and if-else) blocks to alter control flow in a SNAP program

Materials/Preparation

Pacing Guide

Duration Description
5 minutes Welcome, attendance, bell work, announcements
20 minutes Lecture
20 minutes Activity - What Shape is That?
10 minutes Debrief and wrap-up

Note: This lesson may cover too much material for some classes to handle in one day. Feel free to spill over into a second day, splitting the material however works best for your class.

##Instructor's Notes

  1. Lecture

    1. Point out that, so far, our programs have had minimal interactivity

      • There was some user interaction in the shape drawing labs, but no back and forth-- just pushing a key to trigger an action
      • This is not normally how computer programs work
      • Ask students for examples of interactive computer programs
      • Ask students for suggestions for making previous labs or activities more interactive
        • There are no right or wrong answers here-- you're just trying to get students thinking about interactivity

    2. Introduce the block

      • Demonstrate that it functions similar to the block but waits for a response from the user
      • The response is stored in the block and can be referenced later
        • Variables will not be introduced until unit 3, so this block will be somewhat magical for now. You should judge your students' preparedness to handle the details and act accordingly.
      • Emphasize that only one input is stored at a time, and that asking a new question deletes the previous answer

        • For example, the following script, intended to draw a bunch of squares where the user specifies both the size and the number of squares, will not work as intended:

    3. Introduce conditional statements

      • Define "conditional" - a block used to make a choice between executing two different chunks of code
      • Point out the differences between and
        • Namely, if-else provides a choice between two code paths, whereas if simply chooses between executing code or not
      • Emphasize that only one of the bodies, either the if or the else, will ever be executed
      • Show students the relational operators (<, >, and =)
        • These should be fairly intuitive to most students

  2. Activity

    • Direct students to complete the What Shape is That? activity individually or in pairs
      • Help students realize that, although they may seem quite different, parts 2.1 and 2.2 require very similar code

  3. Debrief

    • Discuss one or two students solutions
      • Point out differences between the approaches of different students and lead discussion about advantages and disadvantages
      • Place particular emphasis on the choice between if and if-else blocks
        • Explain that, when conditions are mutually exclusive (as in part 2.1), a series of if vs. if-else blocks can be functionally equivalent
        • When the conditions are not mutually exclusive (as in part 2.2), the choice matters more

BJC Lecture Suggestions

####Good for Classroom Instruction

####Background Information for Instructors

  • Bjorn Hartman Background 0:00-3:30
  • Human Computer Interface(HCI) 3:45-6:00
  • HCI: Design, Computer Science, Applied Psychology 6:00-8:00
  • Iterative Design Cycle 8:00-10:30
  • Understanding Users 10:35-11:35
  • Prototype Interface Examples 11:40-14:00
  • Evaluation (Formative, Summative) 14:50
  • Why Study User Interfaces Ex:Mouse Xy axis, Sketchpad, PC, Tablets 15:00-25:00
  • What had changed? Research: Mainframe to Ubiquitous Computing 25:00-29:30
  • Example Project: Using Dexterity for Computer Interface Video 28:30-29:30
  • Zipf/Power Law Distribution 30:00-32:00
  • HCI Research at Berkeley 32:10-46:25
  • Multi Touch Apps and Toolkits 32:00-End

Accommodation/Differentiation

  • Advanced students can be encouraged to add extra functionality, such as attempting to draw the shape the user is specifying or identifying types of triangles (equilateral, isosceles, scalene)
  • Students who are struggling can be allowed to skip some parts of the tables in 2.1 and 2.2, focusing on just a few cases

Sample Solution

Lab 2.3 Solution

Forum discussion

Lesson 2.3 Inputs and Conditionals (TEALS Discourse account required).