1. CSE4102/5102 Team Project Scratch
Ronald Santos and Alexander Slocum

2. Biography - Mitchel Resnick
Born June 12, 1965
Went to Haverford High School in Pennsylvania
Earned his BA in Physics from Princeton University in 1978
Received his MS in 1988 and PhD in 1992 in Computer Science from MIT
Worked as a tech journalist from
Currently LEGO Papert Professor of Learning at the MIT Media Lab
Focuses on educational tools

3. Biography - Mitchel Resnick
Director of Lifelong Kindergarten group at MIT Media Lab
His group collaborated with LEGO in numerous products such as LEGO Mindstorm
National Science Investigator award 1993
McGraw Prize 2011
AACE EdMedia Pioneer award 2013
Programmable Bricks
Authored several children’s books

4. Brian Silverman and Paula Bonta
Founders of Playful Invention company along with Mitchel Resnick which developed Scratch with LLK
Brian Silverman
From Canada, he went to MIT in 1970s
Created Tinkertoy which was a computer that played tic tac toe
Was the director of research at Logo Computer Systems Inc, which commercialized Logo
Paula Bonta
From Argentina
Has a CS degree and a graduate degree in Education from Harvard
Focuses on software products for children

5. Scratch Motivation
Research to increase increase interest in cs and “enhance development of technological fluency [among youth]”
Reusing, combining, and sharing code with others to create interesting projects
Make cs easier to get into, serves as an introduction to programming and cs concepts
Intended to be used by kids ages 8-16 years old, but has been used in school and university
Harvard
University of Wisconsin
Ohio State

6. Scratch history
Developed by MIT Media Lab Lifelong Kindergarten Group(LLK) and Playful Invention Company
Colorful puzzle-like blocks that you move and drag that snap together instead of text
First version of scratch released in 2003, desktop only
written in Squeak, a modified version of Smalltalk
Scratch 2 released 2013 and was written in AdobeAir
online and desktop version
Online:
Scratch 3 still in development, to be released in 2018
written in JavaScript and HTML
Uses a VM which builds an Abstract Syntax Tree
Open sourced at:

7. Scratch as a programming language
Visual based, makes use of blocks
Imperative
Event-driven
Dynamically-typed
Primitive data types are numbers, strings and booleans
Interpreted, not compiled
A project can be modified as it is being run
Scratch 2.0 blocks and objects are stored as JSON objects
Uses JSON grammar, and parsed and validated with JSON parsers

8. Scratch 1.X

9. Scratch 2.0
Source Code
import
Stage
Run
Stop

10. Blocks
Puzzle-like shapes that serve as the building blocks for any scratch program
Each one differs in shape and color depending on its purpose
In Scratch 2.0 there are currently 12 blocks in total
Control
Variables
List
Event
and so on...
Six different block shapes: Hat, Stack, Boolean, Reporter, C and Cap

11. Variables Block
One of the subcategories of Scratch’s Data blocks, it’s color orange
Holds values as well as strings in variables
Composed of 4 stack blocks and 1 reporter block
Stack blocks serve as the glue for any stack program, comprises majority of Scratch blocks
Reporter blocks are blocks that hold some value, they have round edges

12. List Blocks Another category of Data Blocks, of reddish brick color
Similar in concept to lists and arrays found in other programming languages
No typing. Can hold strings, integers, chars, etc.
Composed of 6 stack blocks, 3 reporter blocks, and 1 boolean block
Can import text files, or other CSV file types, into it

13. Operators Blocks Light green colored blocks
Used for number computations and comparisons as well as string manipulation
Composed of 6 boolean blocks and 11 reporter blocks
Boolean blocks are hexagon shaped blocks that return 0 or 1 based on input
Currently no exponent block, or contains block

14. Control Blocks Golden color blocks
Used to control the flow of a scratch program
Composed of 1 Hat block, 5 C blocks, 3 Stack Blocks, and 2 Cap blocks
Hat blocks denote the starting position of execution for a script
Cap blocks stop the execution of a script or project
C blocks are c-shaped, and serve as the foundation of conditional statements and iteration

15. Control blocks - if/else example
Has an if block and if/else block, no elseif that is typically offered in most languages.
Can nest them together to check for multiple conditions
check for input, controlling objects, comparing values

16. Iteration
Uses, but is not limited to, the change, move, or turn blocks to update a variable
Uses forever, forever if, repeat, and repeat until blocks to create loops to continuously iterate a variable.

17. Example

18. Threads and Synchronization
Other threads are commonly created with when statements
When statements can listen for keyboard inputs, when something is clicked, broadcasts, and more.
These blocks are referred to as event blocks

19. Function Main function is always “when *Green Flag* Clicked”
You can define your own functions using a define block (custom block) so that you can call that function from other scripts

20. Events
Scratch 2.0 has 8 total event blocks, 6 of which are when statements
When *Green Flag* clicked
When *insert key here* pressed
When *insert sprite here* clicked
When backdrop switches to *xyz*
When *compare variables here*
When I receive *broadcast*
2 of which are broadcast statements
Broadcast *xyz*
Broadcast *xyz* and wait

21. Motion/Sound/Costume
Motion blocks have their own category, they control and move whatever sprite their script is under
Sound blocks also have their own category, they make sounds based on what sprite/background their script is under
Each sprite can have multiple costumes, changing between costumes will change the appearance of the sprite.
When changing costumes, switching can just be done by switching to the next costume or switching to a specific costume

22. Examples

23. Custom Blocks
Custom blocks are essentially functions that you create with the define block.
Custom blocks can help simplify a script and make your code much clearer and easier to read and follow.

24. Sprites
A Sprite is a picture/character that is on the screen, visible or not
Each sprite can have multiple scripts, can produce sound, change appearance, move, and be controlled by the user

25. Scratch editor
Scratch editor contains a library of all the blocks for you to drag out when you need them, making building a script very simple
Organizes them based on type of block and what the block does.

26. Impact
Overall, Scratch has done a great job capturing the interests kids can have in programming
It’s a very satisfying language, it allows the ability to easily create games or movies, which is mostly what kids are interested in when they’re introduced to coding.
The blocks you can use are simplified versions of operations and functions of other languages (ex: loops, if statements, broadcasts, etc), making this a great stepping stool language for people interested in getting into coding.
Highly recommended for people with zero coding experience.
harvard study on scratch: malan.pdf
“when asked via surveys at term’s end to reflect on how their initial experience with Scratch affected their subsequent experience with Java, most students (76%) felt that Scratch was a positive influence, particularly those without prior background. Those students (16%) who felt that Scratch was not an influence, positive or negative, all had prior programming experience”