Lesson 1.02: Interactive Mode

Learning Objectives

Students will be able to...

• Define and identify: interpreter, string, integer, float, value, errors, console, expression
• Use the Python interpreter to evaluate simple math expressions
• Distinguish between an integer, float, and string

Materials/Preparation

• Lab - Using the Interpreter
• Associated Reading - section 1.1 of Book
• Ensure all students are able to log into the system
• Go through the lab so that you are familiar with the requirements/results and can assist students

Pacing Guide

Instructor's Notes

1. Do Now
   • Display a photo of the Cloud9 IDE and asks students to identify the three key parts (file tree, terminal, editor) of the IDE.
   • After going over the three parts of the IDE have students check that they can still log into their IDE account.
2. Lesson
   • The part on bottom half of the screen is called a console:
     • The console is a place where you can interact with a program. It can also be called a shell or a terminal.
     • The interpreter runs Python code.
   • To run the Python interpreter, type python3 into the terminal.
     • Make sure all the students are able to do this and then give out the lab worksheet.
3. Lab Part 1
   • Give students time to work on section 1, then pause to ask questions.
     • What does the // do? How is that different from %?
     • What’s the difference between 3.0 and 3?
     • Floats: a data type, number with a decimal point.
     • Integers: a data type, number without a decimal point.
   • Pause to ask questions about section 2.
     • What happened when you typed in a?
     • What do you think that error message mean?
     • String: a data type, characters surrounded in single or double quotes.
   • Pause to ask questions about section 3.
     • What was the difference between the two inputs?
     • Strings can be combined using +.
     • What do you think the error message means?
       • You can’t combine different types!
   • Pause to ask questions about section 4.
     • What error did you get? What do you think that means?
     • What happens when you multiply strings?
4. Lab Part 2
   • Define expression: a combination of values and operators (and variables)
     • Ask students to give an example of an expression
   • Make sure students write down their predictions before going to the interpreter/IDE to check the actual output.
5. Debrief
   • Discuss any surprising/unexpected results.
     • Remind students of adding strings together using +.
     • Talk about how single and double quotes are interchangeable
     • Multiplying strings
     • Order of Operations is the same as what students have learned in math class.
   • Discuss why it might be helpful to have an interactive console. How is it different than snap?

Accomodation/Differentiation

If students are moving quickly, have students practice higher order-of-operations problems. You can also have them practice assigning values to variables.