# 30 min Scratch July 20091 30 min intro to Scratch A Quick-and-Dirty approach Leaving lots of exploration for the future. (5 hour lesson plan available)

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30 min Scratch July 20091 30 min intro to Scratch A Quick-and-Dirty approach Leaving lots of exploration for the future. (5 hour lesson plan available)

30 min Scratch July 20092 Objectives of Scratch unit Intro to visual programming environment Intro to programming with multimedia Story-telling | music-making | game-making Intro to programming concepts objects and attributes sequence, repetition conditions, events, I/O For instructors

30 min Scratch July 20093 Secondary objectives Increase student skills with computers Increase student interest in programming Student achievement on fun project Learn Cartesian coordinates, distance computations, etc.

30 min Scratch July 20094 Computer scientists Create solutions to problems using computers Study information Invent algorithms Write programs to implement the algorithms Reuse a lot of existing program and machine parts

30 min Scratch July 20095 Start scratch and let’s go! Click on the cat icon Or, find “scratch” under “Programs” When home, download from www.scratch.mit.edu www.scratch.mit.edu Scratch programming environment comes up quickly

30 min Scratch July 20096 Click on the “Looks” button at the top left.

30 min Scratch July 20097 Major components At right: the stage with sprite[s] or objects or actors At left: operations and attributes for the sprites Center: scripts or program[s] for the behavior[s] of the sprites Your sprites are actors that you direct with your scripts

30 min Scratch July 20098 Let’s implement an algorithm to average two numbers Make a variable “number1” (click and drag and set) Make another one “number2”

30 min Scratch July 20099 Compute average first as sum Make variable average Drag a “set operation” to script area Drag a + operation Drag variables number1 and number2 to parameters Click to execute

30 min Scratch July 200910 Average script as 4 operation sequence. Change the two numbers and click the sequence to execute the block again.

30 min Scratch July 200911 But Scratch computes with multimedia – color, sound, … Can make cartoons Can create stories Can create video games

30 min Scratch July 200912 The “hello” script Can do it in 57 languages – java, C++, … Scratch Easy in Scratch: select “Looks” operations and drag the “hello operation” onto your center panel. Then double click on this “lego block”: check your sprite behavior at the right Your very first Scratch program!

30 min Scratch July 200913 Make the cat 50% larger 1.Select “Looks” operations 2.Drag the “change size” operator into your script 3.Click and edit for a 50% change (increase) 4.Double click your one operation script 5.Did your cat sprite get 50% bigger?

30 min Scratch July 200914 Scripting a sequence of ops Do ops in the following order by dragging operation blocks into a single connected block Say hello Move 200 steps forward Grow 50% bigger Make the “meow sound”

30 min Scratch July 200915 Some new operations color change (Looks) wait (Control) move (Motion)

30 min Scratch July 200916 Starting a looped script

30 min Scratch July 200917 Exercise: write a script to Make the cat move along a square path Say “hi” at all four corners Wait 3 seconds at each corner Change color at all four corners Double size when back to the original starting location. Say “That’s all folks” when done.

30 min Scratch July 200918 Elements of Scratch: objects Colors Sounds Locations in 2D space Sprites Costumes Variables (to remember the state of things) Events: that are broadcast for communication

30 min Scratch July 200919 Elements of Scratch: control Sequence of operations Loops or repetition Detecting events (key or mouse pressed, sprites overlapping each other, sprites hitting edge of stage, sensor giving value)

30 min Scratch July 200920 Loop constructs in Scratch Repeat N times Repeat forever Repeat forever if some condition exists (suppose I’m a sprite wandering about this lab until someone asks a question)

30 min Scratch July 200921 Conditions can be checked Do something if sprite k hits sprite m Do something if a certain key is pressed Do something is some variable takes a certain value

30 min Scratch July 200922 Interacting with your sprite or story Using mouse Entering a character Asking the user a question

30 min Scratch July 200923 Sprite follows the mouse Try changing the number of steps or the wait time.

30 min Scratch July 200924 Play and examine MadLib Choose the “file” option at the top of the window Choose “open”, then “examples” Choose “stories” Choose “MadLib” and then read the authors instructions Click OK, wait for load, click green flag

30 min Scratch July 200925 About the MadLib story How many actors (sprites)? What is the role of the girl? How are the answers you give 'remembered' and then used in later actions? What is the role of the little whale? What makes the little whale flip around? What makes the big whale spout?

30 min Scratch July 200926 Sprites can interact with each other Can detect when colors overlap in space Can detect when sprites bump into edge of the stage See “bouncing balls” example under Simulations under Examples Interact with this simulation Check out the rather complex scripts

30 min Scratch July 200927 Check out the break dance Open examples; music and dance; break dance How does break dancing begin? What are the roles of the sprites? What events are in the scripts? What should happen when the boom box is clicked?

30 min Scratch July 200928 Experiment with Scratch as time permits Try your own scripts: make moves, sounds, interactions in simple cases Try the examples and learn what makes them work Download Scratch on your own machine and experiment some more Direct a story; or a simulation; or create a video game.

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