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{{pp-semi-indef|small=yes}}{{Short description|Programming language learning environment}}{{about|the programming language|other uses|Scratch (disambiguation)}}{{primary sources|date=February 2022}}{{user-generated|date=October 2023}}{{Use dmy dates|date=February 2022}}

factoids

| logo_alt = Scratch logo| screenshot = Scratch 3.0 editor.png| screenshot caption = Scratch 3.0 editorEvent-driven programming>Event-driven, block-based programming language

• (prototype Scratch 0.1)CONFERENCE, John, Maloney, Leo, Burd, Yasmin, Kafai, Natalie, Rusk, Brian, Silverman, Mitchel, Resnick, Scratch: A Sneak Preview, 29-30 January 2004,www.researchgate.net/publication/221338134, ResearchGate, Section 6: Project status and next steps, Second International Conference on Creating, Connecting and Collaborating through Computing, 10.1109/C5.2004.33,
• (Scratch 1.0)WEB,en.scratch-wiki.info/wiki/Scratch_TimelineMay, Scratch Timeline – Scratch Wiki, en.scratch-wiki.info,
• (Scratch 2.0)
• (Scratch 3.0)

}}

• Scratch 3.0 (online editor) / Scratch 3.29.1 (offline editor) / }}

Scratch Foundation>Logo (programming language)>Logo, Smalltalk, HyperCard, StarLogo, AgentSheets, AgentCubes, EtoysCatrobat,HTTPS://CATROBAT.ORG/WEBSITE=CATROBAT.ORG, Squeak (Scratch 1.x)ActionScript (Scratch 2.0)LEE DATE=2018-12-28URL=HTTPS://WWW.COMPUTHINK.COM.SG/WHAT-YOU-NEED-TO-KNOW-ABOUT-SCRATCH-3-0/WEBSITE=COMPUTHINK, HTML5, JavaScript (Scratch 3.0)FRANG >FIRST=COREY TITLE=PORTING SCRATCH FROM FLASH TO JAVASCRIPT: PERFORMANCE, INTEROPERABILITY AND EXTENSIONS ACCESS-DATE=2024-02-09, bocoup, Microsoft Windows, macOS, Linux (via renderer), HTML5 (via web browser), iOS, iPadOS, and Android (operating system)>Android.BSD licenses>BSD 3-Clause, GPLv2 and Scratch Source Code License| file_ext = .sb, .sprite (Scratch 1.x).sb2, .sprite2 (Scratch 2.0).sb3, .sprite3 (Scratch 3.0)scratch.mit.edu/}}}}Scratch is a high-level, block-based visual programming language and website aimed primarily at children as an educational tool, with a target audience of ages 8 to 16.WEB, scratch, scratch, 11 October 2022, Scratch – About,scratch.mit.edu/about#:~:text=but%20is%20used%20by%20people%20of%20all%20ages., scratch.mit.edu, Users on the site can create projects on the website using a block-like interface. Scratch was conceived and designed through collaborative National Science Foundation grants awarded to Mitchel Resnick and Yasmin Kafai. Scratch is developed by the MIT Media Lab and has been translated into 70+ languages, being used in most parts of the world.WEB,scratch.mit.edu/statistics/, Community statistics at a glance, scratch.mit.edu, 18 May 2019,web.archive.org/web/20160406023520/https://scratch.mit.edu/statistics/, 6 April 2016, live, Scratch is taught and used in after-school centers, schools, and colleges, as well as other public knowledge institutions. As of 15 February 2023, community statistics on the language’s official website show more than 123 million projects shared by over 103 million users, over 804 million total projects ever created (including unshared projects), and more than 95 million monthly website visits.Scratch takes its name from a technique used by disk jockeys called “scratching”, where vinyl records are clipped together and manipulated on a turntable to produce different sound effects and music. Like scratching, the website lets users mix together different media (including graphics, sound, and other programs) in creative ways by creating and “remixing” projects, like video games, animations, music, and simulations.JOURNAL, Lamb, Annette, Johnson, Larry, April 2011, Scratch: Computer Programming for 21st Century Learners,scholarworks.iupui.edu/bitstream/handle/1805/8622/38-4.pdf?sequence=1, PDF, Teacher Librarian, 38, 4, 64–68, 18 May 2019, NEWS,news.mit.edu/2007/resnick-scratch, Creating from Scratch, MIT News, Stephanie, Schorow, 14 May 2007, 18 May 2019,news.mit.edu/2007/resnick-scratch," title="web.archive.org/web/20181013032644news.mit.edu/2007/resnick-scratch,">web.archive.org/web/20181013032644news.mit.edu/2007/resnick-scratch, 13 October 2018, live,

Scratch 3.0

User interface

(File:Dialogo scratch Best Friends 1.png|thumb|A program to change the background and make a character speak)The Scratch interface is divided into three main sections: a stage area, block palette, and a coding area to place and arrange the blocks into scripts that can be run by pressing the green flag or clicking on the code itself. Users may also create their own code blocks and they will appear in “My Blocks”.The stage area features the results (e.g., animations, turtle graphics, either in a small or normal size, with a full-screen option also available) and all sprites’ thumbnails being listed in the bottom area. The stage uses x and y coordinates, with 0,0 being the stage center.With a sprite selected at the bottom of the staging area, blocks of commands can be applied to it by dragging them from the block palette into the coding area. The Costumes tab allows users to change the look of the sprite with a vector and bitmap editor in order to create various effects, including animation. The Sounds tab allows attaching sounds and music to a sprite.When creating sprites and also backgrounds, users can draw their own sprite manually, choose a Sprite from the library, or upload an image.WEB, Science Buddies: Scratch User Guide: Installing & Getting Started with Scratch,www.sciencebuddies.org/science-fair-projects/references/installing-getting-started-with-scratch, ScienceBuddies.org, 2019-05-18,web.archive.org/web/20190518123252/https://www.sciencebuddies.org/science-fair-projects/references/installing-getting-started-with-scratch, 2019-05-18, live, The table below shows the categories of the programming blocks:{| class=“wikitable“|+Block categories in Scratch! colspan=“2” | Category! Notes| Looks| Controls the visuals of the sprite.audio files and effects.| Control| Conditionals, loops, and cloning. Sprite (computer graphics)>Sprites can interact with other sprites, the mouse pointer, and the backdrop.operator (computer programming)>operators, conjunctions, and comparisons .variable (computer science)>variables and lists. Cloud variables are synced across all running versions of the project.Subroutine>functions, accessible as blocks. They have the option to run without a screen refresh.Windows 10 and above in the Microsoft Store, Apple’s macOS, ChromeOS, and Android;WEB, Scratch Desktop,scratch.mit.edu/download, 19 September 2019, this allows the creation and playing of Scratch programs offline. The offline editor can also be downloaded in previous versions, such as Scratch 2.0 and Scratch 1.4 (an archive of older versions is found here).

Extensions

In Scratch, extensions add extra blocks and features that can be used in projects. In Scratch 2.0, the extensions were all hardware-based. Software-based extensions were added in Scratch 3.0, such as text-to-speech voices, along with some new hardware-based extensions like the (Micro Bit|micro:bit). The extensions are listed below.(File:Scratch Extensions Page.png|thumb|389x389px|An example of the Scratch 3 Extensions Page.)

Physical

• LEGO Mindstorms EV3 – Control motors and receive sensor data from the Lego Mindstorms EV3
• Makey Makey – Use Makey Makey to control projects
• LEGO Education WeDo 2.0 – control motors and receive sensor data from the Lego WeDo
• (Micro Bit|micro:bit) – Use of a micro:bit to control projects
• LEGO BOOST – Bring robotic creations to life
• Go Direct Force & Acceleration – Sense pull, push, motion, and spin

Digital

Many of the digital extensions in Scratch 3.0 used to be regular block categories that were moved to the extensions section to reduce clutter. These include:

• Music – Play digital instruments (drums, trumpets, violins, pianos, and more)
• Pen – Draw on the Stage with a variety of thicknesses and color
• Video Sensing – Detect motion with the camera

New digital extensions have also been added in collaborations with commercial companies. These include:

• Text to Speech – Converts words in a text into voice output (variety of voices, supplied by Amazon)
• Translate – Uses Google Translate to translate text from one language into a variety of other languages, including Arabic, Chinese, Dutch, English, French, Greek, Norwegian, and Japanese

A paper published in 2019 by NYU argues and illustrates, for coding music with Scratch, “that the music and sound blocks as currently implemented in Scratch may limit and frustrate meaningful music-making for children, the core user base for Scratch.“WEB, 16 May 2019, Music Making in Scratch: High Floors, Low Ceilings, and Narrow Walls? /,jitp.commons.gc.cuny.edu/music-making-in-scratch-high-floors-low-ceilings-and-narrow-walls/, 2022-02-27, Jitp.commons.gc.cuny.edu,

Scratch Lab

The Scratch LabWEB, Scratch Lab,lab.scratch.mit.edu/, 27 September 2023, lab.scratch.mit.edu, displays experiments from the Scratch Team, intended to explore whether new features may be added to the full website in the future. Experimental features currently under development include:

• Video Sprites – Fill sprites with live video.
• Face Sensing – Make animated costumes and games that interact with your face.
• Animated Text – Bring words to life with colours, fonts, and animations.

Community of users

(File:The MADE Scratch Workshop.jpg|left|thumb|A Scratch programming workshop)Scratch is used in many different settings: schools, museums, libraries, community centers, and homes.NEWS,www.ctvnews.ca/sci-tech/canadian-schools-starting-to-teach-computer-coding-to-kids-1.1799365, Canadian schools starting to teach computer coding to kids, CTV.ca, 2019-05-18, 2014-04-30, Michael, Oliveira,web.archive.org/web/20190518123251/https://www.ctvnews.ca/sci-tech/canadian-schools-starting-to-teach-computer-coding-to-kids-1.1799365, 2019-05-18, live, WEB,www.smm.org/ltc/scratchday, Scratch Day, Science Museum of Minnesota, 18 May 2019, dead,www.smm.org/ltc/scratchday," title="web.archive.org/web/20130408060603www.smm.org/ltc/scratchday,">web.archive.org/web/20130408060603www.smm.org/ltc/scratchday, 2013-04-08, Scratch is designed primarily for users aged 8–16, but it is used by all ages and has a sizeable adult user base as of 2009.JOURNAL, Resnick, Mitchel, Maloney, John, Hernández, Andrés, Rusk, Natalie, Natalie Rusk, Eastmond, Evelyn, Brennan, Karen, Millner, Amon, Rosenbaum, Eric, Silver, Jay, Silverman, Brian, Kafai, Yasmin, 2009, Scratch: Programming for All,web.media.mit.edu/~mres/papers/Scratch-CACM-final.pdf, Communications of the ACM, 52, 11, 60–67, 10.1145/1592761.1592779, 229934947, This wide outreach has created many surrounding communities, both physical and digital. In April 2020, the Tiobe ranking of the world’s programming languages included Scratch in the top 20. According to Tiobe, there are 50 million projects written in Scratch, and every month one million new projects are added.WEB,devclass.com/2020/04/06/kids-programming-language-scratch-nails-top-20-in-latest-dev-rankings/, Kids programming language Scratch nails top 20 in latest dev rankings • DEVCLASS, Fay, Joe, 6 April 2020, DEVCLASS, en-GB, 2020-04-27,

Educational users

Scratch is used as the introductory language because the creation of interesting programs is relatively easy, and skills learned can be applied to other programming languages such as Python and Java.Scratch is not exclusively for creating games. With the provided visuals, programmers can create animations, text, stories, music, and more. There are already many programs that students can use to learn topics in math, history, and even photography. Scratch allows teachers to create conceptual and visual lessons and science lab assignments with animations that help visualize difficult concepts. Within the social sciences, instructors can create quizzes, games, and tutorials with interactive elements. Using Scratch allows young people to understand the logic of programming and how to creatively build and collaborate.WEB,www.avinteractive.com/features/blogs/scratch-av-25-06-2015/, What is Scratch? Is it AV or IT?, 25 June 2015, 18 May 2019, AV Magazine, Martin, Neil,web.archive.org/web/20190518123255/https://www.avinteractive.com/features/blogs/scratch-av-25-06-2015/, 18 May 2019, live, Scratch is taught to more than 800 schools and 70 colleges of DAV organization in India and across the world.WEB, DAV CS Syllabus,davnewpanvel.com/File/5651/Syllabus%20Std-VII%202018-19.pdf, 2019-05-18, dead,davnewpanvel.com/File/5651/Syllabus%20Std-VII%202018-19.pdf," title="web.archive.org/web/20180713122300davnewpanvel.com/File/5651/Syllabus%20Std-VII%202018-19.pdf,">web.archive.org/web/20180713122300davnewpanvel.com/File/5651/Syllabus%20Std-VII%202018-19.pdf, 2018-07-13, WEB, DAV Jharkhand Syllabus,drive.google.com/file/d/0BzYkgDPSlegKbFFncEdwV3czVU0/view, 18 May 2019, In higher education, Scratch is used in the first week of Harvard University’s CS50 introductory computer science course.NEWS, Fun, Not Fear, Is at the Heart of Scratch, a New Programming Language,www.chronicle.com/article/Fun-Not-Fear-Is-at-the-Heart/34008/, The Chronicle of Higher Education, 20 July 2007, 18 May 2019, 0009-5982, Jeffrey R., Young,web.archive.org/web/20190518123249/https://www.chronicle.com/article/Fun-Not-Fear-Is-at-the-Heart/34008/, 18 May 2019, live, WEB, CS50 Syllabus,cdn.cs50.net/2015/x/references/syllabus/syllabus.html, 2019-05-18,cdn.cs50.net/2015/x/references/syllabus/syllabus.html," title="web.archive.org/web/20150317075307cdn.cs50.net/2015/x/references/syllabus/syllabus.html,">web.archive.org/web/20150317075307cdn.cs50.net/2015/x/references/syllabus/syllabus.html, 17 March 2015, live,

Online community

(File:Jumper platformer.png|thumb|“Jumper”, an example of a game created with Scratch 2.0)(File:Abyss scratch 3.0.png|thumb|“Abyss”, an example of a game created with Scratch 3.0)Users of Scratch are called “Scratchers”. Scratchers have the capability to share their projects and receive feedback. Projects can be uploaded directly from the development environment to the Scratch website and any member of the community can view and download the full source code to study or to remix into new projects.BOOK, Proceedings of the 29th International Conference on Human Factors in Computing Systems (CHI ‘11), Monroy-Hernandez, Andres, Hill, Benjamin Mako, Gonzalez-Rivero, Jazmin, Boyd, Danah, ACM, 2011, 3421–30, Computers Can’t Give Credit: How Automatic Attribution Falls Short in an Online Remixing Community, 10.1145/1978942.1979452, 1507.01285, 7494330, BOOK, ICWSM 2010: Proceedings of the 4th International Conference on Weblogs and Social Media, May 23–26, 2010, Hill, B.M, Monroy-Hernández, A., Olson, K.R., AAAI Press, 2010, 978-1-57735-445-1, Washington, D.C., Responses to remixing on a social media sharing website, 844857775, 1507.01284, 2015arXiv150701284M, Scratchers can also create project studios, comment, favorite, and “love” others’ projects, follow other members to see their projects and activity, and share ideas. Projects range from games and animations to practical tools. Additionally, to encourage the creation and sharing amongst users, the website frequently establishes “Scratch Design Studio” challenges.WEB,en.scratch-wiki.info/wiki/Scratch_Design_Studio, Scratch Design Studio, wiki.scratch.mit.edu, 2019-05-18,web.archive.org/web/20190518123252/https://en.scratch-wiki.info/wiki/Scratch_Design_Studio, 18 May 2019, live, The MIT Scratch Team works to ensure that this community maintains a friendly and respectful environment for all people.WEB,scratch.mit.edu/parents/, For Parents, scratch.mit.edu, 18 May 2019,web.archive.org/web/20190404210527/https://scratch.mit.edu/parents, 4 April 2019, live, WEB,scratch.mit.edu/community_guidelines, Scratch Community Guidelines, scratch.mit.edu, 18 May 2019,web.archive.org/web/20190407171658/https://scratch.mit.edu/community_guidelines/, 7 April 2019, live, Educators have their own online community called ScratchEd, developed and supported by the Harvard Graduate School of Education. In this community, Scratch educators share stories, exchange resources, and ask questions.WEB,scratch.mit.edu/educators, Scratch for Educators, scratch.mit.edu, 18 May 2010,scratch.mit.edu/educators," title="web.archive.org/web/20081005234300scratch.mit.edu/educators,">web.archive.org/web/20081005234300scratch.mit.edu/educators, 5 October 2008, live,

Scratch Wiki

The Scratch Wiki is a support resource for Scratch and information about its website, history, and phenomena surrounding it. Although supported by the Scratch Team (the developers of Scratch), it is primarily written by Scratch users (Scratchers) and is hosted independently of the main Scratch website.WEB,en.scratch-wiki.info/wiki/Scratch_Wiki, Scratch Wiki, en.scratch-wiki.info, 18 May 2019,web.archive.org/web/20190512210211/https://en.scratch-wiki.info/wiki/Scratch_Wiki, 12 May 2019, live, There are other wikis in languages besides English available on the Scratch Wiki base domain.

Roles

Roles are displayed as a label under a user’s username on profile pages and on forum posts. To prevent vandalism, new accounts have the “New Scratcher” role, as opposed by the usual “Scratcher” role. Some restrictions are imposed onto New Scratcher accounts, including the inability to use cloud data and a minimum 30 second cooldown period between posting comments.WEB, An explanation of the ‘New Scratcher’ status,scratch.mit.edu/discuss/post/44802/, Discuss Scratch, June 1, 2013, jvvg, January 11, 2024, After a period of time of interacting and creating projects, an account will be eligible to gain the Scratcher role.WEB,mitscratch.freshdesk.com/en/support/solutions/articles/4000177710, What is a Scratcher and how do I become one?, 2021-11-04, 2024-02-10, mitscratch.freshdesk.com, Official moderators and developers of Scratch are labeled as part of the “Scratch Team” and usually have an asterisk at the end of their username.WEB, Scratch Team - Scratch Wiki,en.scratch-wiki.info/wiki/Scratch_Team, 2023-05-26, en.scratch-wiki.info, en, The site also has special types of accounts for Students and Educators to use Scratch in the classroom.WEB, Student and Teacher Accounts - Scratch Wiki,en.scratch-wiki.info/wiki/Student_and_Teacher_Accounts, 2023-05-26, en.scratch-wiki.info, en,

Censorship

In August 2020, GreatFire announced that the Chinese government had blocked access to the Scratch website. At the time, it was estimated that more than three million people in China were using it.WEB, Liao, Rita, 7 September 2020, China bans Scratch, MIT’s programming language for kids,social.techcrunch.com/2020/09/07/scratch-ban-in-china/, 27 April 2021, TechCrunch, en-US, {{dead link|date=February 2024}}{{Citation needed|date=September 2023}} The outlet cited the fact that Macau, Hong Kong and Taiwan were listed as countries on the website.WEB, 8 September 2020, China blocks MIT’s kid-friendly programming language Scratch,developer-tech.com/news/2020/sep/08/china-blocks-mit-kid-friendly-programming-language-scratch/, 19 November 2020, Developer Tech News, en-GB,

Code Base

The source code for the project editor in all three major versions, as well as a majority of the current website, is hosted publicly on GitHub across various repositores.WEB, Scratch Source Code,en.scratch-wiki.info/wiki/Scratch_Source_Code, Scratch Wiki, 8 April 2024, Scratch 3.0 is JavaScript-based, 2.0 is programmed in ActionScript, and the 1.x versions were based on Squeak, which itself is based on Smalltalk-80.2.0 had an experimental JavaScript-based interpreter that was being developed in parallel with the ActionScript version.WEB, We’re seeking contributors to help finish our HTML5 Scratch player (now open sourced!),scratch.mit.edu/discuss/post/174127/, Discuss Scratch, Lightnin, Oct 29, 2013, 18 May 2019, In 3.0, Scratch blocks are implemented using Blockly, a JavaScript library developed by Google for creating block-based visual programming languages.WEB, Blockly,developers.google.com/blockly, Google Developers, NEWS, Pasternak, Erik, 17 January 2019, Scratch 3.0’s new programming blocks, built on Blockly,developers.googleblog.com/2019/01/scratch-30s-new-programming-blocks.html, 2 October 2019, On 13 May 2014, a year after the release of Scratch 2.0, it was announced by a developer on the Scratch Forums that 2.0 would become open source.WEB, Scratch 2.0 Offline Open Source Code!, speakvisually, May 13, 2014,scratch.mit.edu/discuss/post/322347/, Discuss Scratch, Jan 13, 2024,

Events

Scratch Educators can gather in person at Scratch Educator Meetups. At these gatherings, Scratch Educators learn from each other and share ideas and strategies that support computational creativity.WEB,www.meetup.com/pro/scratched/, Scratch Educator, Meetup.com, 18 May 2019,web.archive.org/web/20190421144408/https://www.meetup.com/pro/scratched, 21 April 2019, live, An annual “Scratch Week”, formerly known as “Scratch Day”, is declared in May each year. Community members are encouraged to host an event on or around this day, large or small, that celebrates Scratch. These events are held worldwide, and a listing can be found on the Scratch Day website. Scratch Week is a series focusing on Scratch activities on the Scratch website.WEB,day.scratch.mit.edu/, Scratch Week, 18 May 2019,web.archive.org/web/20190407171614/https://day.scratch.mit.edu/, 7 April 2019, live, Every April Fools’ Day, the Scratch Team will play pranks on users and add Easter eggs, one example being that all event blocks in projects turn into cat versions of the same blocks.

History

In the early 2000s, the MIT Media Lab’s Lifelong Kindergarten group (LLK) was developing visual programming languages targeted towards children.WEB, LLK – Projects – Building-Block Programming,llk.media.mit.edu:80/projects/summaries/bbp.shtml, 19 December 2021, llk.media.mit.edu,llk.media.mit.edu:80/projects/summaries/bbp.shtml," title="web.archive.org/web/20010430112136llk.media.mit.edu:80/projects/summaries/bbp.shtml,">web.archive.org/web/20010430112136llk.media.mit.edu:80/projects/summaries/bbp.shtml, 30 April 2001, In 2003, Mitchel Resnick, Yasmin Kafai, and John Maeda were awarded a National Science Foundation grant for the development of a new programming environment for children to express themselves with code.WEB, NSF Award Search: Award # 0325828 – ITR: A Networked, Media-Rich Programming Environment to Enhance Informal Learning and Technological Fluency at Community Technology Centers,www.nsf.gov/awardsearch/showAward?AWD_ID=0325828, 15 April 2021, www.nsf.gov, The LLK, led by Mitchel Resnick, in partnership with Yasmin Kafai’s team at UCLA worked closely with Computer Clubhouses in Boston and Los Angeles to develop Scratch, grounding its design in the practices and social dynamics of these after-school youth centers. It started as a basic programming language, with no labeled categories and no green flag.WEB,en.scratch-wiki.info/wiki/Development_of_Scratch_1.0, Development of Scratch 1.0, en.scratch-wiki.info, 18 May 2019,web.archive.org/web/20190103004838/https://en.scratch-wiki.info/wiki/Development_of_Scratch_1.0, 3 January 2019, live, Similar to AgentSheetsWEB,www.researchgate.net/publication/3651308, Tactile Programming: A Unified Manipulation Paradigm Supporting Program Comprehension, Composition and Sharing, 15 October 2021, Scratch employed concepts of Tactile Programming later known as blocks-based programming. Scratch was made with the intention to teach kids to program.The philosophy of Scratch encourages the sharing, reuse, and combination of code, as indicated by the team slogan, “Imagine, Program, Share”.WEB,scratch.mit.edu/, Scratch – Imagine, Program, Share, scratch.mit.edu, 18 May 2019,scratch.mit.edu/," title="web.archive.org/web/20110222201702scratch.mit.edu/,">web.archive.org/web/20110222201702scratch.mit.edu/, 22 February 2011, live, Users can make their own projects, or they may choose to “remix” someone else’s project. Projects created and remixed with Scratch are licensed under the Creative Commons Attribution-Share Alike License.WEB,en.scratch-wiki.info/wiki/Creative_Commons_License, Creative Commons License, wiki.scratch.mit.edu, 18 May 2019,web.archive.org/web/20190518123252/https://en.scratch-wiki.info/wiki/Creative_Commons_License, 18 May 2019, live, Scratch automatically gives credit to the user who created the original project and program in the top part of the project page.Scratch was developed based on ongoing interaction with youth and staff at Computer Clubhouses. The use of Scratch at Computer Clubhouses served as a model for other after-school centers demonstrating how informal learning settings can support the development of technological fluency.WEB, ITR: A Networked, Media-Rich Programming Environment to Enhance Informal Learning and Technological Fluency at Community Technology Centers,www.nsf.gov/awardsearch/showAward?AWD_ID=0325828, National Science Foundation, 18 May 2019,web.archive.org/web/20151230194131/https://www.nsf.gov/awardsearch/showAward?AWD_ID=0325828, 30 December 2015, live, Scratch 2.0 was released on 9 May 2013.BOOK, Learn to Program with Scratch, Marji, Majed, No Starch Press, 2014, 978-1-59327-543-3, San Francisco, California, xvii, 1–9, 13–15, The update changed the look of the site and included both an online project editor and an offline editor.WEB,scratch.mit.edu/download, Scratch Desktop, scratch.mit.edu, 2019-05-18,web.archive.org/web/20190406112722/https://scratch.mit.edu/download, 6 April 2019, live, Custom blocks could now be defined within projects, along with several other improvements.WEB,techcrunch.com/2013/05/10/kids-programming-tool-scratch-now-runs-in-the-browser/, Kids’ Programming Tool Scratch Now Runs in the Browser, John, Biggs, TechCrunch, 10 May 2013, 18 May 2019,web.archive.org/web/20170709215339/https://techcrunch.com/2013/05/10/kids-programming-tool-scratch-now-runs-in-the-browser/, 9 July 2017, live, The Scratch 2.0 Offline editor could be downloaded for Windows, Mac, and Linux directly from Scratch’s website, although support for Linux was later dropped. The unofficial mobile version had to be downloaded from the Scratch forums.WEB,scratch.mit.edu/discuss/post/125955/, Discuss Scratch, Updated Scratch 2 Offline Editor (Beta) is now available!, Shane (grokblah), on behalf of the Scratch Team, Aug 29, 2013, 18 May 2019, WEB,www.youtube.com/watch?v=qDFY4O2JU9U, Scratch 2.0 Preview, YouTube, 2013-05-01, MITScratchTeam, 18 May 2019,www.youtube.com/watch?v=qDFY4O2JU9U," title="web.archive.org/web/20140124200207www.youtube.com/watch?v=qDFY4O2JU9U,">web.archive.org/web/20140124200207www.youtube.com/watch?v=qDFY4O2JU9U, 24 January 2014, live, (File:Scratch Website Homepage 2023.png|thumb|The Scratch website’s homepage)Scratch 3.0 was first announced by the Scratch Team in 2016. Several public alpha versions were released between then and January 2018, after which the pre-beta “Preview” versions were released.WEB,en.scratch-wiki.info/wiki/Scratch_3.0, Scratch 3.0, en.scratch-wiki.info, 18 May 2019,web.archive.org/web/20190509215315/https://en.scratch-wiki.info/wiki/Scratch_3.0, 2019-05-09, live, A beta version of Scratch 3.0 was released on 1 August 2018.WEB,medium.com/scratchteam-blog/3-things-to-know-about-scratch-3-0-18ee2f564278, 3 Things To Know About Scratch 3.0, Medium.com, 31 January 2019, 18 May 2019,web.archive.org/web/20190512230529/https://medium.com/scratchteam-blog/3-things-to-know-about-scratch-3-0-18ee2f564278, 12 May 2019, live, for use on most browsers; with the notable exception of Internet Explorer.WEB,scratch.mit.edu/info/faq#scratch3, Scratch 3.0, scratch.mit.edu, 18 May 2019,web.archive.org/web/20190406112722/https://scratch.mit.edu/info/faq/#scratch3, 6 April 2019, live, Scratch 3.0, the first 3.x release version, was released on 2 January 2019.WEB, Scratch 3.0 – Scratch Wiki,en.scratch-wiki.info/wiki/Scratch_3.0, 27 April 2021, en.scratch-wiki.info, On 28 June 2023,WEB, Color Contrast is here!,scratch.mit.edu/discuss/post/7340551/, Discuss Scratch, June 28, 2023, ceebee, on behalf of the Scratch Team, September 5, 2023, the header and links on the Scratch Website changed from blue to purple, and new optional high-contrast block colors were introduced, to make the site easier for colorblind people to read and use.WEB, Coming Soon: Color Contrast in Scratch!,scratch.mit.edu/discuss/post/7292215/, Discuss Scratch, June 5, 2023, ceebee, on behalf of the Scratch Team, September 5, 2023, On March 11, 2019, Scratch separated from MIT Media Lab.WEB, Supporting the Growth of Scratch - Mitchel Resnick - Medium,mres.medium.com/supporting-the-growth-of-scratch-e56dc7f84453, Medium, March 12, 2019, Mitchel Resnick, one of the founders of Scratch, March 5, 2024,

Filetypes

In Scratch 1.4, an *{{Not a typo|.sb}} file was the file format used to store projects.WEB,en.scratch-wiki.info/wiki/.sb, Scratch Wiki – *.sb, 4 October 2015, 7 November 2015, An *{{Not a typo|.sb}} file is divided into four sections:

• “header”, this 10-byte header contains the ASCII string “ScratchV02” in versions higher than Scratch 1.2, and “ScratchV01” in Scratch 1.2 and below
• “infoSize”, encodes the length of the project’s infoObjects. A 4-byte long, 32-bit, big-Endian integer.
• “infoObjects”, a dictionary-format data section. It contains: “thumbnail”, a thumbnail of the project’s stage; “author”, the username of the project’s creator; “comment”, the Project Notes; “history”, the save and upload log; “scratch-version”, the version of Scratch used to save the file;
• “contents”, an object table with the Stage as the root.WEB, Scratch File Format (1.4)/Object Table – Scratch Wiki,en.scratch-wiki.info/wiki/Scratch_File_Format/Object_Table, 2022-02-19, en.scratch-wiki.info, All objects in the program are stored here as references.WEB, Scratch File Format (1.4)/Object Table – Scratch Wiki,en.scratch-wiki.info/wiki/Scratch_File_Format/References, 2022-02-19, en.scratch-wiki.info,

Scratch 2.0 uses the *{{Not a typo|.sb2}} file format. These are zip files containing a .json file as well as the contents of the Scratch project including sounds (stored as {{Not a typo|.wav}}) and images (stored as {{Not a typo|.png}}).WEB, Scratch File Format (2.0),en.scratch-wiki.info/wiki/Scratch_File_Format_(2.0), Scratch Wiki, 2 October 2019, Each filetype, excluding the {{Not a typo|project.json}}, is stored as a number, starting at 0 and counting up with each additional file. The image file labeled “{{Not a typo|0.png}}” is always a 480x360 white image, but “{{Not a typo|0.wav}}” will still be the earliest non-deleted file.The ScratchX experimental version of Scratch used the {{Not a typo|.sbx}} file format.WEB,github.com/LLK/scratchx, LLK/scratchx, GitHub, 16 August 2022, Scratch 3.0 uses the *{{Not a typo|.sb3}} format, which is very similar to *{{Not a typo|.sb2}}, one difference being the sound.WEB, Scratch File Format,en.scratch-wiki.info/wiki/Scratch_File_Format, Scratch Wiki, 2 October 2019,

Older versions

Although the main Scratch website now runs only the current version (Scratch 3.0), the offline editors for Scratch 2.0 (and the earlier Scratch 1.4) are still available for downloadWEB, Scratch 2.0 Offline Editor,scratch.mit.edu/download/scratch2, MIT, 21 September 2019, and can be used to create and run games locally.WEB, 3 Things To Know About Scratch 3.0, 31 January 2019,medium.com/scratchteam-blog/3-things-to-know-about-scratch-3-0-18ee2f564278, The Scratch Team, 21 September 2019, It is still possible to upload projects from the Scratch 2.0 launcher, which are immediately converted into Scratch 3.0 when uploaded to the main site.WEB, Offline Editor (2.0) – Scratch Wiki,en.scratch-wiki.info/wiki/Offline_Editor_(2.0)#Uploading, 2021-04-27, en.scratch-wiki.info, There is also an offline version of Scratch 3.0.

Technology

The editor of Scratch 1.4 and below was written in Squeak, while its online project viewer was written in Java, and a player written in Adobe Flash was later added.WEB, Scratch,wiki.squeak.org/squeak/5833, Squeak/Smalltalk, 7 March 2021, WEB,scratcharchive.asun.co/forums/viewtopic.php?id=57148, Scratch Archived Forums, 7 March 2021, Scratch Forums / Beta Flash player, Scratch 2.0 relied on Adobe Flash for the online version, and Adobe AIR for the offline editor. These have fallen out of favor, and Adobe dropped support for them at the end of 2020.NEWS, O’Donnell, Lindsey, Mozilla Kills Default Support for Adobe Flash in Firefox 69,threatpost.com/flash-default-mozilla-firefox-69/140814/, 21 September 2019, 14 January 2019, NEWS, Adobe Corporate Communications, The Future of Adobe AIR,theblog.adobe.com/the-future-of-adobe-air/, 21 September 2019, 30 May 2019,

Interface

File:Scratch Hello World.png|thumb|A script that lets the sprite say Hello, World!Hello, World!In Scratch 2.0, the stage area is on the left side, with the programming blocks palette in the middle, and the coding area on the right. Extensions are in the “More Blocks” section of the palette.The web version of Scratch 2.0 introduced project autosaving.BOOK, McManus, Sean, Scratch Programming in easy steps, 2013, Easy Steps, Leamington Spa, 978-1-84078-612-5, {{rp|p=23}}The blocks palette in Scratch 2.0 is made of discrete sections that are not scrollable from one to the next; the table below shows the different sections:{| class=“wikitable” style="text-align: left“|+Interface sections in Scratch!scope=“col” colspan=“2” style="background: #efefef;” | Category!scope=“col“| Notes valign=“top” Motion| Moves and changes the position of sprites Events| Event handlers valign=“top” Looks| Controls the visuals of the sprite Control| Conditionals and loops valign=“top” Sound| Audio files, sequences Sensing| Sprite interaction valign=“top” Pen| Draw on the canvas Operators| Mathematical operators valign=“top” Data| Variables and arrays More Blocks| Functions, return value is always voidScratch 2.0 introduced the backpack, which can be used to transfer scripts, sprites, costumes, and sounds between projects.{{rp|pp=14-15}}

1.4 sounds

Scratch 2.0 changed how sounds were imported, so many Scratch 1.4 sounds stopped working. (The project file was changed from *{{Not a typo|.sb}} to *{{Not a typo|.sb2}}).

Features

Scratch uses event-driven programming with multiple active objects called sprites. Sprites can be drawn, as vector or bitmap graphics, from scratch in a simple editor that is part of Scratch, or can be imported from external sources. Scratch 3.0 only supports one-dimensional arrays, known as “lists”, and floating-point scalars and strings are supported but with limited string manipulation ability. 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.Scratch 2.0 does not treat procedures as first class structures and has limited file I/O options with Scratch 2.0 Extension Protocol, an experimental extension feature that allows interaction between Scratch 2.0 and other programs.WEB, Scratch Extension, MIT,en.scratch-wiki.info/wiki/Scratch_Extension, 18 May 2019,web.archive.org/web/20190518123255/https://en.scratch-wiki.info/wiki/Scratch_Extension, 18 May 2019, live, The Extension protocol allows interfacing with hardware boards such as Lego MindstormsWEB, EV3+Scratch Extension, Scratch extension GitHub, Code & Circuit,kaspesla.github.io/ev3_scratch/, 18 May 2019,kaspesla.github.io/ev3_scratch/," title="web.archive.org/web/20160120204258kaspesla.github.io/ev3_scratch/,">web.archive.org/web/20160120204258kaspesla.github.io/ev3_scratch/, 20 January 2016, live, or Arduino.WEB, Preliminary Scratch extension for talking to Arduino boards running Firmata, Scratch extension GitHub, Damellis,github.com/damellis/A4S, 18 May 2019,web.archive.org/web/20180116143517/https://github.com/damellis/A4S, 16 January 2018, live, ! (Build Your Own Blocks)“>

Snap! (Build Your Own Blocks)

A more advanced visual programming language inspired by Scratch is Snap!, featuring first class procedures (their mathematical foundations are called also lambda calculus), first-class lists (including lists of lists), and first-class truly object-oriented sprites with prototyping inheritance, and nestable sprites, which are not part of Scratch.WEB, Snap! – Build Your Own Blocks, University of California, Berkeley,snap.berkeley.edu/, 18 May 2019,web.archive.org/web/20190516160757/https://snap.berkeley.edu/, 16 May 2019, live, Snap! (previously “BYOB“) was developed by Jens MönigWEB,scratch.mit.edu/users/Jens/, Jens on Scratch, Scratch, Jens, Mönig, 18 May 2019,web.archive.org/web/20190518123251/https://scratch.mit.edu/users/Jens/, 18 May 2019, live, WEB,www.chirp.scratchr.org/blog/?m=201105, BYOB 3.1 – Prototypal Inheritance for Scratch, 31 May 2011, Chirp Blog, Jens, Mönig, 18 May 2019, dead,www.chirp.scratchr.org/blog/?m=201105," title="web.archive.org/web/20131206131246www.chirp.scratchr.org/blog/?m=201105,">web.archive.org/web/20131206131246www.chirp.scratchr.org/blog/?m=201105, 6 December 2013, with documentation provided by Brian HarveyWEB,people.eecs.berkeley.edu/~bh/, Brian Harvey, Electrical Engineering and Computer Sciences, 18 May 2019,web.archive.org/web/20190403045124/https://people.eecs.berkeley.edu/~bh/, 3 April 2019, live, WEB,scratch.mit.edu/users/bharvey/, bharvey, Scratch, 18 May 2019,web.archive.org/web/20190518123251/https://scratch.mit.edu/users/bharvey/, 18 May 2019, live, from University of California, Berkeley and has been used to teach “The Beauty and Joy of Computing” introductory course in CS for non-CS-major students.WEB,inst.eecs.berkeley.edu/~cs10/fa11/, CS10 : The Beauty and Joy of Computing, EECS Instructional Support Group Home Page, 18 May 2019,inst.eecs.berkeley.edu/~cs10/fa11/," title="web.archive.org/web/20140123111318inst.eecs.berkeley.edu/~cs10/fa11/,">web.archive.org/web/20140123111318inst.eecs.berkeley.edu/~cs10/fa11/, 23 January 2014, live, Both of them were members of the Scratch Team before designing “Snap!”.WEB,forum.snap.berkeley.edu/t/relationship-with-the-scratch-team/1277, Relationship With the Scratch Team,

ScratchJr

In July 2014, ScratchJr was released for iPad, and in 2016, ScratchJr for Android. Although heavily inspired by Scratch and co-led by Mitch Resnick, it is nonetheless a complete rewrite designed for younger children—targeting ages 5 through 7.WEB, About ScratchJr,www.scratchjr.org/about/info, scratchjr.org, 19 September 2019,

Community-made modifications

Due to the open source nature of Scratch, numerous forks and browser extensions have been created by the community that aim to improve or modify the user experience. Scratch Addons is one such browser extension that adds a multitude of toggleable themes and quality of life features to both the online editor and website.WEB, Frequently Asked Questions,scratchaddons.com/docs/faq/, 2024-01-07, Scratch Addons Docs, en, TurboWarp is a fork of the Scratch 3.0 editor that compiles the Scratch blocks into JavaScript code when a project is run, meaning projects can run up to 200x faster, with results varying heavily depending on the project.WEB, How TurboWarp runs Scratch projects 10-100x faster {{!, TurboWarp Documentation |url=https://docs.turbowarp.org/how |access-date=2024-01-07 |website=docs.turbowarp.org |language=en}}WEB, TurboWarp - Run Scratch projects faster,turbowarp.org/, 2022-04-17, turbowarp.org, TurboWarp can also export projects to standalone HTML5, Android apps, Bundle (macOS) and EXE files.WEB, TurboWarp Packager,packager.turbowarp.org/, 2024-01-07, packager.turbowarp.org, Users can also create their own extensions for Scratch 3.0 using JavaScript.WEB, Scratch 3.0 Extensions,github.com/LLK/scratch-vm/blob/develop/docs/extensions.md, 19 September 2019, Github, MIT, Although the intention for Scratch 3.0 was to allow unofficial JavaScript extensions to be developed by users, it was abandoned due to moderation risks. As a result, the official site doesn’t allow JavaScript extensions to be added, but several modifications of the Scratch Engine do. Before 2.0, a number of Scratch forksWEB, Scratch Modification,en.scratch-wiki.info/wiki/Scratch_Modification, live,web.archive.org/web/20190518123253/https://en.scratch-wiki.info/wiki/Scratch_Modification, 18 May 2019, 18 May 2019, Scratch Wiki, Lifelong Kindergarten Group at the MIT Media Lab, {{Better source needed|reason=Citation is the Scratch Wiki, which is officially considered an unreliable source. Please find a non-wiki source for your info.|date=March 2024}} were created using the source code of Scratch 1.4. These programs usually only included a few extra blocks not present in Scratch.WEB, Blocks,en.scratch-wiki.info/wiki/Blocks, live,web.archive.org/web/20190518123256/https://en.scratch-wiki.info/wiki/Blocks, 18 May 2019, 18 May 2019, Scratch Wiki, {{Better source needed|reason=Citation is the Scratch Wiki, which is officially considered an unreliable source. Please find a non-wiki source for your info.|date=March 2024}}

See also

• Blockly, an interface used by Scratch to make the code blocks.
• Snap! (programming language)
• Swift Playgrounds
• Alice (software)
• Twine (software)
• Lego Mindstorms EV3
• Kodu Game Lab
• Code.org
• Programmable Cricket
• PWCT
• Visual programming language
• Pencil Code (programming language)

References

{{reflist}}

External links

{{Commons category}}

• {{Official website}}
• {{Curlie|Computers/Programming/Languages/Smalltalk/Squeak/Scratch|Scratch}}
• Scratch Lab

{{Video game engines}}{{Authority control}}