Data Type: All values in a programming language have a "type" - such as a Number, Boolean, or String - that dictates how the computer will interpret it. For example 7+5 is interpreted differently from "7"+"5"
Expression: Any valid unit of code that resolves to a value.
Variable: A placeholder for a piece of information that can change.
==: The equality operator (sometimes read: "equal equal") is used to compare two values, and returns a Boolean (true/false). Avoid confusion with the assignment operator "=",
Global Variable: A variable whose scope is "global" to the program, it can be used and updated by any part of the code. Its global scope is typically derived from the variable being declared (created) outside of any function, object, or method.
If-Statement: The common programming structure that implements "conditional statements".
Local Variable: A variable with local scope is one that can only be seen, used and updated by code within the same scope. Typically this means the variable was declared (created) inside a function -- includes function parameter variables.
Variable Scope: dictates what portions of the code can "see" or use a variable, typically derived from where the variable was first created. (See Global v. Local)
Models and Simulations: a program which replicates or mimics key features of a real world event in order to investigate its behavior without the cost, time, or danger of running an experiment in real life.
for loop: A typical looping construct designed to make it easy to repeat a section of code using a counter variable. The for loop combines the creation of a variable, a boolean looping condition, and an update to the variable in one statement.
Return Value: A value sent back by a function to the place in the code where the function was called form - typically asking for value (e.g. getText(id)) or the result of a calculation or computation of some kind. Most programming languages have many built-in functions that return values, but you can also write your own.