Lesson 1: Animating Sprites

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Lesson 1: Animating Letters with Costumes
This is an example of a sprite.
A sprite can be any thing, person, or place you want it to be. You control
what a sprite does. Sprites start out knowing how to do some things, like
move, turn, and talk, but it is your job to make sprites do more complicated
actions by combining the things it already knows. So in a way, you are
teaching the sprite what to do. You can teach it to walk, jump, pick up
objects, go through mazes, and many other things.
Let us see what Scratch looks like when you start it up. You tell a sprite to
do something by putting a Script Block into the Main Script Window. The
Script Blocks you can choose from are organized into categories for Motion,
Looks, Sound, Pen, Control, Sensing, Numbers, and Variables. We’ll be
learning all about those different commands. To pick which Sprite you are
controlling, you select it from the window on the bottom right. You can see
your sprites acting out their commands in your World Preview Window.
In this lesson you will teach the letters of your name to change into a
different picture when you click on them. To do this, you must create those
letters and them tell each of them everything it must do, step by step. We’ll
see there are 4 steps.
1. Import a single letter that is in your name and a different picture it
should switch to.
2. Make the letter change to the picture when it is clicked.
3. Change the program so it switches 10 tends between costumes.
4. Make all of the letters of your name behave like this
We’ll implement each of those steps.
1) Import a letter and a picture
We aren’t going to be using the cat Sprite in this program, so we’ll start by
deleting it. You can do this by “right clicking” on the cat and then selecting
“delete” from the pop-up menu.
Next, we will import one of the letters in your name. You do this by
clicking the “folder” button under the Stage; you’ll then see that the different
Sprites are organized into different categories and folders. We want to look
at the Letters. Double-click on Letters to open it. You’ll then see folders for
different styles of letters; double-click on a style (e.g., Scratch) and then
double-click on the letter you want (e.g., ‘A’).
Now, you’ll see your letter in the middle of the Stage. Let us now pick a
costume that you want that letter to switch to. Each Sprite can have different
costumes associated with it; you can make a sprite look different by
changing its costume. Click on the Costumes tab. You’ll see the first
costume is the letter you imported. Pick a new costume by clicking Import.
You can then look through the Animals, Fantasy, People, Things, and
Transportation sprites included with Scratch. You might want to pick an
object that starts with the same letter as the letter it is switching from.
(Each costume has a name associated with it. You should always give good
descriptive names to your Sprites and their Costumes. Rename your two
costumes “letter” and “picture” to describe them.)
Your costumes should look something like this when you are done.
2) Switch between costumes
To make it look like your letter is switching into the other picture, you need
to tell the sprite to switch between different costumes.
Tell the cat to switch costumes by going back to the Scripts tab, click
in the Top Left Menu, and then find
it into the script window. If you double click on
will keep switching between the two costumes. Try it out.
and drag
the sprite
We want the letter to switch costumes not when we double-click on those
instructions, but instead when a person clicks on the letter. To make the
letter respond to clicking, add “when Sprite1 clicked” before next
costume. That command will then start when the sprite is clicked.
You can find this command by clicking
Menu. Test out your scripts now.
in the Top Left
3) Switch between costumes many times
Right now, your letter switches to the picture and back one time when you
click on it. What if you want to make the costumes switch many times after
the user clicks it just once?
One way to do this would be to put multiple next costumes on top of each
other. But, that would take us a long time to drag the blocks into place. A
better way is to tell Scratch to repeat the commands multiple times. You
can do this with the repeat block. You can find this control structure under
the Control menu. Put the command next costume inside of the repeat
block.
When you test your program, how does it look? It doesn’t look right,
because you aren’t able to see the different costume; Scratch is switching to
the next costume before you have time to see the first one.
We can fix this problem by having Scratch wait before it moves to the next
command. Under the Control menu, you will find this command:
. Insert the wait command after the next costume command.
How does this look?
You probably think that it looks like the costumes are switching too slowly.
Waiting for 1 second between switches is too long. Experiment with smaller
wait times, like .5 seconds or .25 seconds. Use whatever value you think
looks best!
You can also change the number of times the repeat block runs; right now, it
is set to switch costumes 10 times. You can change this value if you like.
4) Copying to new letters
We now want to make new costumes for all of the letters of your name. To
do this, you will first Import a New Sprite for each letter of your name.
The letters will not show up in the order you want them on the Stage, so use
the mouse to drag them to the places you want them.
Next, you need to select new costumes for each of the letters. For each
letter, click on the Costumes tab and then click the Import button. Select
new pictures that you like. (It is much more fun, but more time consuming,
if you draw your own pictures. To do this, click on Paint after New
costume instead of Import. Scratch comes with a Paint tool that you can
explore on your own.)
After you have all of your letters and pictures, you need to write the scripts
for each. You could drag and drop the Script blocks like you did for your
first letter, but there is an easier way in Scratch. You can copy scripts from
one sprite to another by dragging them on top of the new Sprite. When you
do this, you should then see that the sprite says Scripts:1 underneath of it.
If you look at the Scripts for the Sprite, you will see that one small thing
changed. Instead of the control block saying “When Sprite1 clicked” it now
says “When Sprite2 clicked.” Each Sprite has its own scripts and its scripts
need to be activated by different events. Scratch knows that you want to
activate these scripts now when this sprite is clicked.
Test this out now. Everything should work as planned!
One problem you might see is that some of your pictures could be too large.
If you want some of the costumes to be smaller, click on the Edit button
next to the costume. You will then be running the Paint editor which allows
you to change costumes in any way you want. You can click on the Shrink
button multiple times to make the costume a little smaller.
5) Saving your work
You are now done with your first Scratch lesson. You’ve created your name
from letter sprites that switch to different pictures when the user clicks on
them.
Save your project so you can use it later. Save it as “Lesson 1” in a new
folder “Lessons”. To make a new folder, click the new folder button in the
save window.
Things to Remember
You control what a Sprite does. Each sprite has its own Scripts, Costumes,
and Sounds.
To make a sprite do something, you put commands in the Script box. When
Script Blocks are connected, they activate one at a time, starting from the
top. You can double-click on commands to make them execute. You can
copy a group of commands by right clicking a selecting “duplicate”. You
can disconnect a list of commands by grabbing the commands that should be
removed.
Sprites can have different costumes. A sprite can switch between costumes
to change the way it looks. You can edit and make new costumes for a
sprite. You can make a costume smaller by clicking on Edit and then
clicking multiple times on the Shrink button
You can make a sprite respond to being clicked with the When Sprite
Pressed control block at the the top of a list of commands. The commands
underneath it will start when that sprite is clicked.
The repeat control block runs the commands that are inside of the loop a
number of times; the number of times is specified at the top of the loop.
Final Code
This is what your script should look like for each letter of your name. The
word “Sprite1” will be different for each Sprite.
Week 1 Homework
For next week, you should finish this project for your first name. Feel free
to explore Scratch and do things a little differently than we wrote in this
lesson.
For example, you can draw your own letters or pictures as costumes. You
can change the amount of time Scratch waits between switching costumes.
You can change the number of times Scratch repeats the costume changes.
You can even activate the costume changes in a different way: instead of
using the control block when Sprite1 clicked to start the script, you could
use the control block When key pressed; this control block is activated
when the user presses that particular key on the keyboard; you probably
want each letter to be activated with its own key name.
You can install Scratch on your home computer with your parents’ help.
They can go to the website http://scratch.mit.edu and click on the
Download button on the upper right part of the page. Scratch is free for
both Windows and Macintosh machines. If you have any problems using
Scratch on your computer at home, you can borrow an XO laptop for future
weeks.
We do not have USB flash drives this first week, but we should have them
by next week. Next week, one of the things we will learn is how to save
Scratch projects on USB drives so you can move your projects between
home and school.
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