Topic outline

  • General

  • Topic 1

    Introduction

    Scratch 2 is an improvement on Scratch 1.4 as it allows the user to write procedures.

    This allows code to be broken into manageable blocks and even pass variables (called parameters ie measure across) between procedures. This means the same block of code can be run more than once, and it can return different values. For example, code to run a robot forward may not need any values to say how long. and does not return a result to the computer.

    A function is a special type of procedure that returns only one value. For example, if I asked you what today is, there is only one answer. Tomorrow, the same question would give a different answer but again only one.

    A function that did this could be called "today".

    Download Scratch 2 here.

    Beware, you have to install Adobe Air 2 as well.

    • Topic 2

      Data and data types

      Computers are really good at manipulating data very quickly. It follows some idea of data and data types is required.

      It is important that the computer "knows" what sort of data it is dealing with so it can store it into memory in the right way. Data in Scratch can be stored in a computer in three different ways.

      • characters
      • numbers
      • boolean

      to name a few.

      Because Scratch is not strongly data typed, it can be flexible in the way stores data

      • characters can become strings
      • numbers can be integers or real numbers
      • Topic 3

        Variables

        A variable is a name given to a space in memory a value like a number or a name can be stored in. 

        You can create a variable by pressing this button.

        make a var

        Variables tutorial

        Scratch variables

        You can then assign a value or change a value using the following command blocks. variable
        • Topic 4

          Procedures

          A procedure is a block of code that is written as a stand alone that can be called from a driver routine and used over and over again.

          You can aloso save these procedures and create "libraries" of code that can be shared.

          Scratch 2.0 Custom blocks
          jump
          • Topic 5

            Messages

            Messages were a way to call code used in Scratch 1.4.

            Using procedures is more efficient.

            • Topic 6

              Parameter passing

              A parameter is a variable that can be passed from procedure to procedure.

              There are three types of parameters

              • global for all sprites
              • local for one sprite
              • cloud that is stored externally on a server

              Variables explained

              private

              • Topic 7

                Structured programming

                • Topic 8

                  Top down planning

                  • Topic 9

                    Capturing data : files

                    • Topic 10

                      Sorting

                      • Topic 11

                        Lists

                        list (called an array in other programming languages) is a tool that can be used to store multiple pieces of information at once. 

                        They are in the form

                        x(1) = All Star
                        x(2) = Hey Ya!
                        x(3) = Hey Ya!
                        x(4) = All Star
                        x(5) = Hey Ya!
                        x(6) = All Star

                        Each entry is called an element. 

                        example list

                        Create a list

                        Just go to data and create a list.

                        Opposite are the tings you can do to manipulate the elements in the list.

                        Lists and arrays are used frequently in storing data. They are a powerful way of creating databases and manipulating data into information.

                        The data is sorted, searched, ranked, calculated and graphed, to name a few. It is the way the NSA in America keeps electronic tabs on you.

                        list blocks

                        A fun example

                        As a way of exploring sentence construction, folks came up with this kind of game. 

                        The following is a random sentence generator. It contains personal pronouns, adjectives and nouns. 

                        You can store them in lists, then use random numbers to generate your own sentences.

                        Danger

                        Non smarty pants kids may be tempted to create sentences that they think funny but might offend others.

                        Don't.

                        cat 2

                        cat code

                        Vocabulary : 

                        List, array, element, data, information, data base, 

                        • Topic 12

                          Programming peripherals

                          • Topic 14

                            Algorithms

                            • Topic 15

                              x

                              • Topic 16

                                x

                                • Topic 17

                                  x

                                  • Topic 18

                                    x

                                    • Topic 19

                                      x

                                      • Topic 20

                                        x