This document introduces Scratch, a programming environment for creating computer programs and interactive stories. It outlines four lesson objectives: identifying the major parts of the Scratch environment; understanding how sprites and blocks work; understanding the concept of a computer program; and working with simple animation and sound. The document guides the reader through creating their first program involving a cat walking on a stage using sprites, costumes, scripts, and blocks. It also discusses parallel processing and tasks the reader with creating a dancing sprite program.
2. Starter Activity: Scratch Website
Explore the scratch website
http://scratch.mit.edu
Scratching The Surface
3. Scratching The Surface
In this lesson you will learn about the Scratch
programming environment and the basic terms
used in the program. You will create your first
computer program based on a cat walk scenario.
Lesson
Objectives
Identify the major parts of the scratch environment
Understand how sprites and blocks work
Understand the concept of a computer program
Work with simple animation and sound
4. Watch the Scratch Intro video, this will introduce
you to Scratch and its screen layout.
Scratching The Surface
5. A Scratch program contains sprites (characters)
that “perform” on a stage. Sprites and the stage
have three kinds of properties (or settings).
Scripts: These are the instructions that control a
sprite. Scripts are made from blocks.
Costumes/Backgrounds: Costumes are “outfits” for
a sprite. Backgrounds are just like costumes but for
the stage.
Sounds: These are sounds that sprites or the stage
can use.
Scratching The Surface
6. Task 1: Up on the Catwalk
Follow the steps outlined in the Catwalk video
which is in the programming in scratch folder in
Groupwork to create your first computer
program.
Scratching The Surface
If you get struck, look back at the video.
7. Congratulations – you have just started your
journey to become a computer programmer!
Scratching The Surface
8. Putting Things in Order
•Blocks in the same script get executed (carried
out) in sequence, one after the other.
•Blocks in separate scripts can sometimes be
executed at the same time. This is called parallel
processing – having the computer do more than
one thing at a time.
•For example, if you have several scripts, they will
all get executed together when the green flag is
clicked.
Scratching The Surface
9. Task 2: Dance Away
Create a program to make a sprite dance in time to
music. Watch the Dancing Queen video which is in
the programming in scratch folder in Groupwork to
give you some inspiration.
Scratching The Surface
10. Plenary: Question 1
Look at the section of code below that controls a
sprite.
What you think the user will see when the green
flag is clicked.
Scratching The Surface
11. Plenary: Question 2
Look at the section of code below that controls a
sprite.
What do you think the user will see when the green
flag is clicked.
Scratching The Surface
12. Plenary: Question 3
In the stack of blocks below, how many times
does the sprite move 10 steps?
Scratching The Surface
13. Plenary: Question 4
A programmer wants the cat to dance to some
music. However, the cat doesn’t start dancing
until after the music has finished!
Why is this?
Scratching The Surface
14. Scratching The Surface
Keywords
Identify the major parts of the scratch
Understand how sprites and blocks work
Understand the concept of a computer program
Work with simple animation and sound
Objectives
Sprites
Blocks
Costumes
Processing
Motion
Control
Coordinates
Code
Hinweis der Redaktion
The sprite appears not to move Why? The computer carried out the instructions too quickly for us to see any movement.
The sprite didn’t move. Why? Both scripts get executed at the same time – in parallel – thereby “ cancelling each other out”.
Eight times.
The computer plays sound hip-hop until it is completed before going on to the next instruction. The programmer could have done one of two things: used a play sound hip-hop block had the play sound until done block as part of another when flag clicked script.
