5.2. Logo Part 2

This lesson introduces the concept of parameters as a means of creating procedures that can be more easily reused in a program. Students use an updated version of the Logo app that includes parameters for the forward and turn procedures to change the size of the angles allowing the creation of more complex shapes.

CSP Framework
Big Idea 3: Algorithms and Programming (AAP)
Enduring Understanding AAP-2: The way statements are sequenced and combined in a program determines the computed result. Programs incorporate iteration and selection constructs to represent repetition and make decisions to handle varied input values.
Learning Objective AAP-2.L: Compare multiple algorithms to determine if they yield the same side effect or result.
Skill 1.D AAP-2.L.2 Essential Knowledge AAP-2.L.2: Algorithms that appear similar can yield different side effects or results.
Learning Objective AAP-2.M.a: For algorithms: a. Create algorithms. Learning Objective AAP-2.M.b: For algorithms: b. Combine and modify existing algorithms.
Skill 2.B AAP-2.M.2 Essential Knowledge AAP-2.M.2: Knowledge of existing algorithms can help in constructing new ones. Some existing algorithms include: -determining the maximum or minimum value of 2 or more numbers - computing the sum or average of 2 or more numbers - identifying if an integer is or is not evenly divisible by another integer - determining a robot’s path through a maze
Enduring Understanding AAP-3: Programmers break down problems into smaller and more manageable pieces. By creating procedures and leveraging parameters, programmers generalize processes that can be reused. Procedures allow programmers to draw upon existing code that has already been tested, allowing them to write programs more quickly and with more confidence.
Learning Objective AAP-3.A.a: For procedure calls: a. Write statements to call procedures. Learning Objective AAP-3.A.b: For procedure calls: b. Determine the result or effect of a procedure call.
Skill 4.B AAP-3.A.1 AAP-3.A.2 AAP-3.A.3 AAP-3.A.4 AAP-3.A.5 AAP-3.A.6 AAP-3.A.7 AAP-3.A.8 AAP-3.A.9 Essential Knowledge AAP-3.A.1: A procedure is a named group of programming instructions that may have parameters and return values. Essential Knowledge AAP-3.A.2: Procedures are referred to by different names, such as method or function, depending on the programming language. Essential Knowledge AAP-3.A.3: Parameters are input variables of a procedure. Arguments specify the values of the parameters when a procedure is called. Essential Knowledge AAP-3.A.4: A procedure call interrupts the sequential execution of statements, causing the program to execute the statements within the procedure before continuing. Once the last statement in the procedure (or a return statement) has executed, flow of control is returned to the point immediately following where the procedure was called. Essential Knowledge AAP-3.A.5: The exam reference sheet provides procName (arg1, arg2, …) as a way to call PROCEDURE procName(parameter1, parameter 2, …) which takes zero or more arguments; arg1 is assigned to parameter1, arg2 is assigned to parameter2, and so on. Essential Knowledge AAP-3.A.6: The exam reference sheet provides the procedure DISPLAY(expression) to display the value of expression, followed by a space. Essential Knowledge AAP-3.A.7: The exam reference sheet provides the RETURN(expression) statement, which is used to return the flow of control to the point where the procedure was called and to return the value of expression. Essential Knowledge AAP-3.A.8: The exam reference sheet provides result ß procName(arg1, arg2, …) to assign to result the value of the procedure being returned by calling PROCEDURE procName(parameter1, parameter2, …) Essential Knowledge AAP-3.A.9: The exam reference sheet provides procedure INPUT(), which accepts a value from the user and returns the input value.
Learning Objective AAP-3.B: Explain how the use of procedural abstraction manages complexity in a program.
Skill 3.C AAP-3.B.5 Essential Knowledge AAP-3.B.5: Using parameters allows procedures to be generalized, enabling the procedures to be reused with a range of input values or arguments.
Learning Objective AAP-3.C: Develop procedural abstractions to manage complexity in a program by writing procedures.
Skill 3.B AAP-3.C.1 AAP-3.C.2 Essential Knowledge AAP-3.C.1: The exam reference sheet provides PROCEDURE procName(parameter1, parameter2, …){ } which is used to define a procedure that takes zero or more arguments. The procedure contains block of statements. Essential Knowledge AAP-3.C.2: The exam reference sheet provides PROCEDURE procName(parameter1, parameter2, …) { RETURN(expression) } which is used to define a procedure that takes zero or more arguments. The procedure contains block of statements and returns the value of expression. The RETURN statement may appear at any point inside the procedure and causes an immediate return from the procedure back to the calling statement.

Professional Development

The Student Lesson: Complete the activities for Complete the activities for Mobile CSP Unit 5: Lesson 5.2 Logo Part 2.

Materials

• Presentation system (LCD projector/Interactive whiteboard)
• Access to computer, laptop, or Chromebook (install the Companion app on Chromebooks)
• Access to mobile device with the Companion app installed or access to the emulator installed on the computer or laptop. 
• Logo Part 2 Tutorial (video or handout)
• Graphing paper - You can print graph paper from www.printablepaper.net

5.2.1. Learning Activities

Estimated Length: 45 minutes

• Hook/Motivation (5 minutes): Discuss the Logo Part 1 tutorial and its limitations. First ask the students to summarize what the program did. Then ask the students what they think might make the program better. Hopefully students were frustrated by the weakness of the forward and move commands in the previous lesson and will be receptive to introducing parameters into the forward(N) and turn(D) procedures.

  Another possible hook is to go through the song This Old Man and have students point out the repeated lines and then create parameterized procedure calls for each verse like verse("one","thumb"), verse("Two","shoe"), etc. to introduce procedural abstraction with parameters.

• Experiences and Exploration (30 minutes):
  • Parameters Introduction (15 minutes): Introduce the concept of parameters for the forward and turn procedures. On the board, develop new algorithms for different sized squares or have the students rewrite their drawFace procedure from the previous lesson using the more powerful set of procedures. Discuss how parameters make the procedures more general (more abstract) and why this is useful. Discuss how the students have begun to evaluate the Logo 1 algorithms for efficiency. As they will see, there are more efficient ways to write algorithms and they should check that the algorithms they will write for the Logo 2 lesson are efficient and clear.
  • Programming (20 minutes): Have the students open the Logo Part 2 (with parameters) tutorial and have them complete the exercises on their own. You may need to go over angles. The shapes are drawn using exterior angles where 360/number of sides. So for a triangle, it's 360/3 sides = 120 degree turns. See solution file below under Assessments.
• Rethink, Reflect, and Revise (10 minutes): Review the lessons learned about algorithms and procedural abstraction. Have students post a reflection on their portfolio and complete the interactive exercises. One of the main lessons should be that our abstractions — i.e., the particular set of procedures we use — have an enormous impact on our algorithms. Procedural abstraction makes it easier an algorithm by raising the level of abstraction. To illustrate this, ask them to think about what the algorithm for a face would if we had to describe it completely in terms of just forward and turn rather than in terms of square, triangle, and circle.

AP Classroom

The College Board's AP Classroom provides a question bank and Topic Questions. You may create a formative assessment quiz in AP Classroom, assign the quiz (a set of questions), and then review the results in class to identify and address any student misunderstandings.The following are suggested topic questions that you could assign once students have completed this lesson.

Suggested Topic Questions:

• Topic 3.9 Developing Algorithms
• Topic 3.12 Calling Procedures
• Topic 3.13 Developing Procedures

Assessment Opportunities and Solutions

Solutions Note: Solutions are only available to verified educators who have joined the Teaching Mobile CSP Google group/forum in Unit 1.

• Logo 2 Project Solutions
• Logo 2 .aia file
• Quizly Solutions
• Portfolio Reflection Questions Solutions

Assessment Opportunities

You can examine students’ work on the interactive exercise and their reflection portfolio entries to assess their progress on the following learning objectives. If students are able to do what is listed there, they are ready to move on to the next lesson.

• Interactive Exercises:
• Portfolio Reflections:
  LO X.X.X - Students should be able to ...
• In the XXX App, look for:

Differentiation: More Practice

If students are struggling with lesson concepts, have them review the following resources:

• Procedures and Parameters Review Sheet submitted by Anthony Truss at Conard High School in CT.

Background Knowledge:

Teaching Tips: Meaningful Parameter Names

This lesson is a good time to reinforce the use of meaningful names for variables, including parameters. Students should avoid the use of ambiguous letters (such as x or y) as parameter names and choose something that is easily recognizable and understandable - and indicates the kind of data that it represents. One clue for students is that if they are using good names, their block will read out aloud like sentences in English.

5.2.2. Professional Development Reflection

Discuss the following questions with other teachers in your professional development program.

I am confident I can teach this lesson to my students.
• 1. Strongly Agree
• 2. Agree
• 3. Neutral
• 4. Disagree
• 5. Strongly Disagree