Scratch 2

Time Education C&P

• Publisher: Time Education C&P
• Year: 2020
• eBook ISBN: 9791197120183
• Topic: Education
• Subtopic: Education Technology

The ability to code will become an essential skill in a fast-changing future. Coding education is a part of the national curriculum in many countries, such as the UK, Finland, Japan, and China. Students are able to acquire computational thinking skills, which can help them to analyze and solve problems logically. CodingTime is a coding education academy located in Seoul, South Korea. For many years, we have helped students achieve their educational goals. This book will help students to excel in programming. Students will learn how to use the Scratch program to code in a fun and easy way. They can make algorithms and get a glimpse of mathematics and science principles used in programming, while building their own project.

Chapter5. Mouse input

Mouse input

1. Touch the hedgehog

2. Grab the grasshopper

01 Touch the hedgehog

What to make

When you place the mouse over the hedgehog, its appearance will change.
A sound will play as it changes.

Play the project

Go to this website:
https://scratch.mit.edu/projects/440089087

Changing the costumes when sprite is clicked

How to make

How does the shape and appearance of the hedgehog change?
(HINT: Check the [Costumes] tab of the hedgehog sprite.)

When does the hedgehog change its looks?
(HINT: See sensing palette.)

What sound can you hear when the hedgehog changes its looks?
(HINT: See the [Sounds] tab of the hedgehog sprite.)

New blocks

Make sounds

Sense if the mouse pointer is touching the sprite

Programming

Create a new project by clicking [File] > [New] or [Create].

Delete the cat by clicking [x]
button. Click the new sprite
button and select [Hedgehog]
sprite.

Drag and place the hedgehog
anywhere on the stage.

Click the [Costumes] tab
to see the names of the
costumes. Pick the costumes
the sprite will change to. (For
example, Hedgehog-a and
Hedgehog-d.)

Set the Hedgehog’s costume
as Hedgehog-a when green
flag is clicked.
[Events] > [When Green Flag
Clicked]
[Looks] > [Switch Costume to
Hedgehog-a]

Check if the mouse pointer
touches the hedgehog.
[Control] > [If O Then]
[Sensing] > [Touching O?]

When the mouse pointer
touches the hedgehog,
make the costume switch to
hedgehog-d.
[Looks] > [Switch Costume
to O▼] - click ▼ to select
hedgehog-d.

After costume switches, have
it make a “pop” sound.
[Sound] > [Start Sound O▼]

Place the blocks under the [switch
costume to hedgehog-a] block.

Click the green flag to run the project.
To see what happens, touch the hedgehog with your mouse.

Nothing happens because
after the green flag button is
clicked, the computer senses a
mouse movement only once.
Therefore, the [forever] block is
essential for repeatedly sensing
a mouse input.

[Control] > [Forever]

Click the green flag to run the project.
To see what happens, touch the hedgehog with your mouse.

On the bottom right corner, click the [choose a backdrop] button and select
[Garden-rock] backdrop.

Change the title to “Touch the hedgehog.”

Practice

Besides switching the costume and making a “pop” sound, make other events
happen when the mouse-pointer touches the hedgehog.

memo

02

02 Grab the grasshopper

What to make

A grasshopper is jumping everywhere!
Click it and it will say “You got me!”

Play the project

Go to this website:
https://scratch.mit.edu/projects/440089252/

Repeating until a condition is satisfied & Clicking the mouse

How to make

How does the grasshopper move?

When does the grasshopper stop moving?

New blocks

Go to random position

Join two conditions

Sense if the user clicks the mouse

Repeat until a condition
is satisfied

Sense when mouse touches a sprite

Programming

Create a new project by clicking [File] > [New] or [Create].

Delete the cat by clicking
[x] button. Click the new
sprite button and select
[Grasshopper] sprite.

Downsize it from 100 to 50.

Make the grasshopper go to a
random position.

[Events] > [When Green Flag Clicked]
[Motion] > [Go to random position]

The grasshopper should not move
infinitely. It should repeat only until a
specific condition is satisfied.

[Control] > [Repeat Until O]

The condition that should be satisfied is clicking the grasshopper. In
other word...

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