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{{about|the programming language|its editor|User Interface|its website|Scratch Website|the current version of Scratch|Scratch 3.0}}{{Scratch Mod
|name = Scratch
|image = Scratch logo.svg
|version = [[Scratch 3.0]]
|os = Any modern {{wp|web browser}} that supports {{wp|JavaScript}}
|developers = [[Scratch Team]]
|prolanguage = {{wp|HTML}}/{{wp|JavaScript}}
|website = [[Scratch Website]] ([[scratch:|here]])
|released = Yes}}[[File:ScratchCat3.0.svg|thumb|120px|The [[Scratch Cat]], the official Scratch mascot.]]
'''Scratch''' is a free, educational, [[block]]-based [[Programming Language|programming language]] that is developed by the [[Lifelong Kindergarten Group]] at the [[Massachusetts Institute of Technology]] (MIT). The current version, [[Scratch 3.0|3.0]], can be used in the [[Online Editor|online editor]] [[projects:editor|here]] or downloaded [[scratch:download|here]] (the previous version, [[Scratch 2.0|2.0]], can be downloaded [[scratch:download/scratch2|here]]). It is targeted towards kids ages 8–16.<ref>[[scratch:faq#about-scratch]]</ref>

Scratch is designed to be fun, educational, and easy to learn. It has tools for creating interactive [[Story Projects|stories]], [[Game Projects|games]], [[Art Projects|art]], [[Simulation Projects|simulations]], and [[Project Types|more]]. Users program in Scratch by dragging [[blocks]] from the [[Block Palette|block palette]] and attaching them to other blocks like a {{wp|jigsaw puzzle}}. Many connected blocks are called [[script]]s. These scripts then control [[sprite]]s that can perform actions on the [[stage]]. This method of programming (building code with blocks) is referred to as "[[wikipedia:Drag and drop|drag-and-drop]] programming". Scratch also has its own built-in [[Paint Editor|paint editor]] and [[Sound Editor|sound editor]].

[[Project]]s that [[Scratcher|users]] create can be [[sharing|shared]] to the [[Scratch Website]], making them visible to everyone. One of the core features of Scratch is [[remix]]ing, in which users can change and re-share other users' projects. Users can communicate and discuss in the [[Scratch Community|Scratch community]] by posting [[Comment (website feature)|comments]] and using the [[Discussion Forums]]. As of February 2024, there are over 123 million registered [[Scratcher|users]] and 150 million shared [[project]]s.<ref>[[scratch:statistics]]</ref>

== History ==
{{main|Scratch Versions}}
Scratch [[Development of Scratch 1.0|began development]] in 2003 and was released to the public in [[Timeline#2007|2007]]. The idea behind Scratch was inspired by work in the [https://www.media.mit.edu/projects/computer-clubhouse/overview/ Computer Clubhouse] where children wanted to create interactive stories, games, and animations, but there were no tools that could easily do this. The Lifelong Kindergarten Group was also inspired by Logo and EToys.{{cite post|mres|23/1/2021|We were inspired, in part, by our work at the Computer Clubhouse after-school centers. We saw that kids there wanted to created their own interactive stories, games, and animations, but there were no tools that were right for them. Also, we were inspired by some some existing programming languages for kids (Logo and EToys). We borrowed lots of ideas from those languages, but added our own ideas (a type of remixing!) to create Scratch.|[[users:mres/#comments-116963575]]<!--please internet archive, it's getting long to load-->}} [[Scratch 1.0]], the first stable version, lacked many of the features now present. At that time, only the offline editor existed, and the website was a small blog where projects could be uploaded and played. As Scratch became more popular, the website grew with it. [[Scratch 1.1]], [[Scratch 1.2]], [[Scratch 1.3]], and [[Scratch 1.4]] were released. At this point, Scratch had millions of users, projects, and many new features.

Upon the release of [[Scratch 2.0]] in [[Timeline#2013|2013]], the website and [[Scratch User Interface|User Interface]] were changed. Scratch continued to grow, achieving 30 million users and projects in 2018.<ref>https://web.archive.org/web/https://scratch.mit.edu/statistics/</ref> [[Scratch 3.0]], which was released on January 2, [[Timeline#2019|2019]], updated the look and feel of the website and editor and added many new features, such as new [[extension]]s. Scratch grew massively after the release of Scratch 3.0, and in 2024, Scratch achieved 125 million users and projects.<ref>http://web.archive.org/web/20240225112858/https://scratch.mit.edu/statistics/</ref>


Because of the growth of the Scratch community, the [[Scratch Foundation]] was created and it has led the design, development, and support of Scratch since March 2019.<ref>https://medium.com/@mres/supporting-the-growth-of-scratch-e56dc7f84453</ref> MIT will continue to collaborate closely with the Scratch Foundation.

== Uses ==
Scratch is widely used in schools around the world as a means of introducing basic computer programming to children. It is also used outside of schools. Some teachers even use [[Student and Teacher Accounts|Teacher Accounts]] to monitor students while having fun in the Scratch Community. Children and even adults gain an understanding of the fundamentals of programming with Scratch and often move on to [[Alternatives to Scratch|other programming languages]]. During their use of Scratch, people can create, [[remix]], and [[Collaboration (group)|collaborate]] with others on [[Project|Scratch projects]].

== Layout ==
{{main|User Interface}}[[File:Scratch 3.0 program sections.png|thumb|384px|The Scratch 3.0 user interface with labeled sections.]]
In designing the language, the creators' main priority was to make the language and development environment simple, intuitive, and easily learnable by children who had no previous programming experience. There is a strong contrast between the powerful multimedia functions and multi-threaded programming style and the rather limited scope of the Scratch programming language.

The [[User Interface|user interface]] for the Scratch development environment divides the screen into several panes: on the left is the blocks palette, in the middle the scripts area, and on the right the stage and sprite list. The blocks palette has code fragments (called "blocks") that can be dragged onto the scripts area from the palette to make programs. To keep the palette organized and for ease of use, it is organized into nine groups of blocks: motion, looks, sound, control, events, sensing, operators, variables, and more blocks.

Projects that users create can be shared on the [[Scratch Website]] and viewed by others.

== Origin of the Word ==
"Scratch" was used as the title for The Lifelong Kindergarten Group's programming language, as it is to do with "scratching" referring to music.
{{quote|Scratching is a DJ or turntablist technique used to produce distinctive sounds by moving a vinyl record back and forth on a turntable while optionally manipulating the crossfader on a DJ mixer.|[[wikipedia:Scratching|Wikipedia]]}}
Likewise, within Scratch, a user takes different bits of code (blocks), put them together, and have made something new.
{{quote|We take the name "Scratch," from the way that hip-hop disk jockeys scratch with music. They take pieces of music and then combine them together in unexpected and creative ways.|Mitchel Resnick, Lifelong Kindergarten Group at MIT}}<ref>[[yt:knFykmLljos]]</ref>

=== Variants of the Word ===
The word "Scratch" has spawned other phrases that have become popular amongst users of Scratch:
* [[New Scratcher Status|New Scratcher]] {{-}} A user who has the New Scratcher status
* [[Scratcher]] {{-}} A user of Scratch
* Scratching {{-}} A verb which means to use Scratch
* Scratched {{-}} A project that is an attempted replica of another game. e.g. "Pac-man Scratched"
* [[Scratch Time]] {{-}} The timezone that the [[Scratch Forums|forums]] are set in (EST/EDT)
* [[Scratch Team]] {{-}} The moderators and developers of the website.
* Scratch On! {{-}} A phrase coined by the [[Scratch Team]], and used by them (although has been adapted by other Scratchers as well) to encourage users, meaning "carry on using Scratch"

== Motto ==
Scratch's motto is "Imagine, Program, Share". This follows the basic principle of creating a project: one comes up with an idea ("Imagine"), programs the idea in Scratch ("Program"), and then publishes it in the community ("Share").

== Versions ==
{{main|Scratch Versions}}
Scratch is currently on [[Scratch 3.0|version 3.0]]. The online editor was officially released on January 2, 2019, and the offline editor at a later date.{{when}} Its predecessor is [[Scratch 2.0]], which was released on May 9, 2013. The previous, older versions are [[Scratch 1.4]], [[Scratch 1.3]], [[Scratch 1.2]], [[Scratch 1.1]], and [[Scratch 1.0]]. Each version had significant changes, especially the jump from 2.0 to 3.0. Not only did the program update with version 2.0 and 3.0, but the entire website was redone.

== Features ==
* Scratch is [[Wikipedia:Turing completeness|Turing complete]].
* It is primarily [[Event Based Programming|event-driven]] and is not [[Object-Oriented Programming|object-oriented]].<ref>https://web.media.mit.edu/~jmaloney/papers/ScratchLangAndEnvironment.pdf</ref><ref>[[post:3978326]]</ref>
* Scratch has [[variable]]s and [[list]]s for data storage, and [[array]]s can be replicated.
* Scratch is ''not'' atomic in repetition, though that can be simulated with [[Single Frame]] programming.
* Scratch 2.0 onwards supports [[procedure]]s and [[recursion]].
* Scratch has many simplified [[casting]] rules. However, data is not [[wikipedia:First-class citizen|first-class]] {{-}} there are no first-class lists, sprites, or procedures (lambda).

== OS Permissions ==
Scratch has limited hardware/OS access and is a very safe program. The following can be accessed by Scratch:
* Ambient volume
* Mouse position relative to the Scratch frame
* Key presses, only if Scratch is in focus
* In Scratch 3.0, some movements are provided as sensor values, using a webcam for image input.
* The filesystem can be accessed while in development, but not while running.
* Scratch can communicate externally to a [[LEGO WeDo Construction Set|LEGO WeDo]], [[LEGO BOOST]], [[EV3|Lego Mindstorms EV3]], [[Makey Makey]], [[micro:bit]], [[Go Direct Force & Acceleration Extension|Go Direct Force & Acceleration]], or [[Raspberry Pi]] set.

[[Scratch Modification]]s may offer more OS permissions.

== ScratchJr ==
{{main|ScratchJr}}
[[ScratchJr]] is a programming language based on Scratch that utilizes visual-centric content to introduce 5 to 7-year-olds (its intended audience) to the programming world. It was developed in part by some members of the Scratch Team, and it is available on iOS and Android as a mobile app.

== See Also ==
* [[Getting Started with Scratch]]
* [[Scratch 3.0]] {{-}} the current version of the Scratch website and program
* [[Scratch Website]] {{-}} the website that Scratch is hosted on
* [[Wikipedia:Scratch (programming language)|Scratch on Wikipedia]] {{-}} the description of Scratch on Wikipedia
* [[Scratch Timeline]]
* [[Scratch Wiki]]
* [[Programming Language]] {{-}} what they are and their uses to the world of computer science

==References==
<references />

[[de:Scratch]]
[[ru:Скретч]]
[[id:Scratch]]
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[[fr:Langage Scratch]]
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<noinclude>[[Category:Scratch Program]]</noinclude>