alice-teacher Variables

[Wendy Evans]

I tell my students to imagine a wall full of little boxes. Each box, we can label with a name (the variable name), that way we know where to find it. Then, I explain how that little box can be empty (null) or it can hold a value. What type of value depends on us and how we define it (number, string, Boolean...).  We can store something in the box, like a number, and then we can add to it, subtract from it etc... It can start with a value in it, or we can ask the user to put something in it.  The box (variable) name doesn't change, but what is stored in the box (variable) changes throughout the program as we need it to.


Miss Wendy Sue Evans
Conestoga Valley High School
Math and Computer Science Teacher



From: alice-teachers-bounces+wendy_evans=cvsd.k12.pa.us at lists.andrew.cmu.edu [mailto:alice-teachers-bounces+wendy_evans=cvsd.k12.pa.us at lists.andrew.cmu.edu] On Behalf Of EILEEN PELUSO
Sent: Tuesday, November 06, 2012 8:06 AM
To: Alice educators
Subject: Re: alice-teacher Variables

I often lead in by reminding students that computers hold a lot of information, and that in this particular program that we're working on, we need to keep a few pieces of information (then I get specific, e.g. it's a yes/no answer from the user, it's the number of seconds left in our game).  Then I say, "To do that, we use something called variables.  We give each piece of information that we need to keep a name, and when we use that name, what we actually get is that piece of information."  Then, when we go to define our variables, we talk about how information can be of different types, e.g. number, etc., and the notion of giving it an initial value.  The first variable I have students define is a Boolean.  We ask the user a yes/no question (specifically, do they want to see their character do a little magic), and then we use an if/else to make the character act accordingly.

From: alice-teachers-bounces+pelusoem=lycoming.edu at lists.andrew.cmu.edu<mailto:alice-teachers-bounces+pelusoem=lycoming.edu at lists.andrew.cmu.edu> [mailto:alice-teachers-bounces+pelusoem=lycoming.edu at lists.andrew.cmu.edu] On Behalf Of Prem Pathuri
Sent: Monday, November 05, 2012 11:24 PM
To: Alice educators
Subject: alice-teacher Variables

I am having a hard time explaining to one of my students EXACTLY what a variable is and I told him to refer to the book but it made it more confusing for him. So could somebody please give me a simple yet concise answer?




Prem Pathuri
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