"Scratch" - what is it, definition of the term
A block‑based visual programming platform created by the MIT Media Lab that lets users construct interactive stories, games, animations, and simulations by dragging and snapping colored command blocks together; it runs in a web browser, offers a built‑in library of sprites and sounds, and provides an online community for publishing and remixing projects.
Detailed information
The visual programming environment created at MIT enables users to assemble commands from colored blocks that interlock like puzzle pieces. Execution proceeds from the top of each script, eliminating syntax errors common in text‑based languages. The interface consists of a stage for visual output, a sprite palette, and a script area where blocks are dragged and dropped.
Key capabilities include:
- Motion blocks that control sprite position, direction, and speed.
- Looks blocks for changing costumes, displaying text, and applying visual effects.
- Sound blocks that play recorded audio or generate tones.
- Event blocks that trigger scripts on clicks, broadcasts, or timer events.
- Control blocks for loops, conditional branches, and waiting periods.
- Sensing blocks that detect keyboard input, mouse position, and collisions between sprites.
- Operators for arithmetic, string manipulation, and logical comparisons.
- Variables and lists for storing numeric or textual data, accessible across all sprites.
The platform supports extensions that add hardware interaction, such as connecting to microcontrollers, robotics kits, and sensor arrays. Extensions are loaded through a dedicated menu, allowing scripts to read analog values, control LEDs, or communicate via Bluetooth.
Educational use focuses on computational thinking. Learners design projects that simulate biological entities—ticks, insects, lice, fleas—by defining movement patterns, life‑cycle stages, and interaction rules. For example, a tick simulation may use random motion blocks to wander across a background, collision detection to attach to a host sprite, and a timer to model feeding intervals. An insect model can incorporate looping structures to animate wing beats, while variables track population counts. Louse and flea projects often employ cloning blocks to generate multiple instances, combined with sensing blocks that detect proximity to a host sprite and trigger a jump behavior.
Export options include publishing to an online community, generating standalone HTML files, or converting projects to executable formats for offline use. The community repository provides remixable projects, enabling learners to study and adapt existing codebases.
Overall, the block‑based environment offers a low‑barrier entry point for programming concepts while supporting sophisticated simulations of biological agents such as ticks, bugs, lice, and fleas.