Glossary

Actor

A term used to refer to sprites and the role they play as they interact with one another on the stage.

Animated GIF

A graphic is made up of two or more frames, each of which is displayed as an automated sequence when the GIF file is displayed.

Boolean

A term used to represent data that has either of two values, true or false.

Brightness

The application or restriction of the intensity of light in a graphic image.

Broadcast Message

An electronic message sent between sprites as a means of coordinating application activity.

Code Block

A graphical command used in the creation of a script.

Collision

An event that occurs whenever two sprites come into contact with one another on the stage.

Compression

The process of reducing the size of sound and graphics files in order to reduce the overall size of Scratch applications.

Conditional Logic

The process of executing sets of code blocks based on whether or not a tested condition proves true.

Costumes

Images that are used to represent a sprite on the stage.

Data

A piece of information collected, stored, modified, and processed during application execution.

Debugger

A program or utility that can be used to execute an application within a special environment that allows programmers to slow and monitor the execution of an application’s script as it runs.

Decimal

A floating point or real number.

Endless Loop

A loop that does not have a means for terminating its execution.

Event Handling

The process of initiating script execution based on the occurrence of predefined events, such as a mouse click, the pressing of a keyboard key, or the clicking of a sprite.

Fisheye

A graphic effect that can be applied to a sprite or background in order to magnify a portion of its image.

Ghost

A graphic effect that fades the appearance of a costume or background, making it look transparent.

Global Variable

A variable that can be modified by any script in an application.

Gradient

A color created by blending together the foreground and background colors.

Hat Block

A code block that creates event-driven scripts.

IDE (Integrated Development Environment)

A graphical application development environment designed to facilitate program development.

Integer

An absolute or whole number that does not have a decimal point.

Java

A popular web-based programming language that is a prerequisite for executing a Scratch application on the Scratch website.

Local Variable

A variable that can be modified only by scripts belonging to the sprite in which the variable is defined.

Logical Error

An error created by a mistake made by the programmer when developing the logic implemented by a script.

Looks Blocks

Code blocks that affect sprite and background appearance and display text.

Loop

A collection of one or more code blocks that are repeatedly executed.

Monitor

A small block that displays the value currently assigned to the code block.

Mosaic

A special graphic effect that creates an image made up of repeated instances of a sprite or background.

Motion Blocks

Code blocks that control sprite placement, direction, rotation, and movement.

MP3

An audio file that utilizes advanced compression technology while retaining high audio quality.

Nest

The process of embedding one set of code blocks within another set of code blocks.

Numbers Blocks

Code blocks that perform mathematical operations, logical comparisons, rounding, and other arithmetic operations.

Order of Precedence

The set of rules that is followed when evaluating a numeric expression.

Paint Editor

A Scratch program that supports the creation of graphics files to be used as the basis for creating and modifying sprites and backgrounds.

Pen

A virtualized drawing tool that can be used to draw on the stage.

Pen Blocks

Code blocks that can be used to draw using different colors and pen sizes.

Pixelate

A special graphic effect that displays a sprite or background at a lower resolution than the resolution at which it was created.

Project

A collection of sprites, scripts, backgrounds, and sounds that is used as the basis for creating Scratch applications.

Real Number

A number that includes a decimal number.

Reporter Block

A code block that has either rounded or angled sides and is specifically designed as a mechanism for providing input for other code blocks to process.

Rotation Center

The point on a sprite that remains in position when a sprite is rotated.

Run-time Error

An application error that occurs when an application attempts to perform an illegal action.

Scope

A term that refers to the area within an application where a variable’s value can be accessed and modified.

Scratch Board

A special piece of hardware that you can buy from the Scratch website and attach to your computer in order to collect and process environmental and user-provided input.

Scratch Cards

PDF files that you can print and use as a quick reference for performing certain tasks.

Script

A collection of code blocks that outlines the programming logic that influences the operation of a sprite.

Sensing Blocks

Code blocks that can be used to determine the location of the mouse-pointer, its distance from other sprites, and whether a sprite is touching another sprite.

Sound Blocks

Code blocks that control the playback and volume of musical notes and audio files.

Sprite

A two-dimensional image drawn on a transparent background that can be moved around the stage. You can change its appearance using different costumes.

Squeak

A cross-platform programming language used to develop Scratch.

Stack Blocks

Code blocks with a notch at the top or a bump at the bottom that can be snapped together with other bocks to define a script’s programming logic.

Stacks

Another term for a script.

Stage

The background area on the Scratch IDE upon which sprites are displayed during application execution.

String

A set of characters that can be displayed within thought and speech bubbles.

Tempo

A measurement of the speed, in beats per minute, at which a drum or note is played.

Troubleshooting

The identification, location, and elimination of programming errors, or bugs, that prevent applications from executing properly.

Variable

A location in memory where an individual piece of data is stored.

Variable Scope

Identifies the location within an application where the variable’s value can be modified.

Variables Blocks

Code blocks that can be used to store data used by applications when they execute.

Wave

A file with a .wav extension that supports the storage and playback of audio files.

Whirl

A special graphic effect that twists and distorts a portion of a costume or background.