Lecture notes for mini-Scratch unit for middle school math

1. Intro to Programming
Algebra-Geometry

2. Computer Programming?
 What is programming?
 The process of writing, testing, and maintaining
the source code of computer programs.
 Telling the computer what to do
 Why learn to program?
 Develops logic and problem-solving skills
 Improves attention to detail
 It’s fun!

3. But I’m Not a Geek!
 Until recently, programming required
knowledge of computer language syntax

4. Anyone Can Program!
 New tools, like Scratch, allow ANYONE to
create computer programs without learning
complicated syntax.

5. Programming with Scratch
 Open Scratch from either the desktop icon or
Start Menu

7. Homework
 Make sure you have the latest version of
Scratch installed on your Tablet PC
 Finish working through the Scratch Getting
Started Guide
 Feel free to experiment and explore!

8. Scratch Syntax: Part 1
Algebra-Geometry

9. Statements
 In programming, a statement is simply a
directive that tells the computer to do
something. Think of it as a command or an
instruction.
 In Scratch, any block whose label reads like a
command is a statement.

10. Boolean Expressions
 Sometimes, you only want a statement to be
executed under certain conditions. Such
conditions are defined in terms of Boolean
expressions.
 In programming, a Boolean expression is
an expression that is either true or false. In
Scratch, any block shaped like an elongated
diamond is a Boolean expression.

11. Boolean Expressions
 One such block is:
After all, it is either true that the mouse button
is down or it is false.
 Another such block is:
After all, it is either true that some number is
less than another number or it is false.
 With Boolean expressions can we construct
conditions.

12. Conditions
 In programming, a condition is something
that must be true in order for something to
happen.
 A condition is thus said to "evaluate to true"
or "evaluate to false."
 In Scratch, any block whose label says "if,"
"when," or "until" is a sort of conditional
construct.

13. Conditions
 If Construct: Instruct a sprite to say hello
only if, say, the user has depressed the
mouse button:
 If-Else Construct: Instruct a sprite to say
hello or goodbye, depending on whether the
user has depressed the mouse button:

14. Conditions
 When Construct: Instruct a sprite to do
something when an event occurs:
 When Construct: Instruct a sprite to wait to
do something until a condition is true:

15. Loops
 In programming, a loop can induce multiple
executions of statements.
 In Scratch, any block whose label begins with
"forever" or "repeat" is a looping construct.

16. Follow Me
Follow Me applet

17. Homework
 Complete the Cat Walk Project
 You may wish to use the Scratch Reference
Guide and the Programming Concepts
Handout as resources
 Completed projects need to be submitted via
Interact by the due date.

18. Scratch Syntax: Part 2
Algebra-Geometry

19. Variables
 In programming, a variable is a placeholder
for some value, much like x and y are popular
variables in algebra.
 In Scratch, variables are represented with
blocks shaped like elongated circles,
uniquely labeled by you.

20. Threads
 In programming, a thread is like a mini-
program within a program that can execute at
the same time as other threads.
 In Scratch, any block whose label begins with
"when" essentially demarks the start of a
thread.

21. Events
 An event is a signal from one thread to
another.
 Blocks whose labels begin with "broadcast"
signal events whereas blocks whose labels
begin with "when" handle events.

22. Pac Man and Pong
 Games like Pac Man
use Threads
 A Variable could be
added to Pong

23. Homework
 Complete the Tweak a Game Project
 Remember that the video tutorials can be
very helpful
 Completed projects need to be submitted via
Interact by the due date. Don’t forget to
include your brief written summary!

24. Scratch Syntax:
Your First Game
Algebra-Geometry

25. Adding a Level
 Levels can be added using threads and
events.

26. Copter Game Flight Code

27. Copter Game—One Level

28. Homework
 Complete the Your First Game Project
 You may wish to use the Copter Game and
Levels program as resources
 Completed projects need to be submitted via
Interact by the due date.