SCRATCH

 

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APP – BALLOONS EVERYWHERE

 

DESCRIPTION

 

In this program, you will create an application that will generate balloons randomly on the screen.  This will involve learning how to create clones (copies) of sprites.  We will also make use of coding on the stage.

 

STEPS

 

STEP 0 – NEW APPLICATION

 

  • You need to start with a new application.  So choose File > New.  Of course, you need to save any previous work beforehand or it will be lost.

 

STEP 1 – PICK THE BALLOON SPRITE

 

  • Add a new sprite and choose the balloon.

 

 

STEP 2 – SELECT THE STAGE

 

  • At the bottom right, select the stage (by clicking on “Stage”).  Notice that no sprite is selected anymore.  So now, if you add code, you are adding code to the stage, not to a sprite.

STEP 3 – GENERATE A BALLOON EVERY SECOND

 

  • Add the forever control. (Control)
  • Inside, wait 1 second. (Control)
  • Then, still inside, create a clone of balloon. (Control)
  • Place all of the above inside a Green Flag clicked event block (Event).

 

STEP 4 – TEST YOUR PROGRAM (NOTHING HAPPENS)

 

  • Test your program.  Nothing happens because all of the copies of the balloon are at the exact same place.  So you don’t see them.

 

STEP 5 – CODE INSIDE BALLOON

 

  • Click on your balloon sprite to select it (at the bottom).
  • You should see an empty coding section.
  • Add the event When I start as a clone which is strangely located in Control.
  • Under the event, add the block go to (random position) in Motion.

 

STEP 6 – TEST YOUR PROGRAM

 

  • A new balloon should appear every second.

 

STEP 7 – CUSTOMIZE YOUR PROGRAM

 

  • You can now customize this.  A few ideas:
    • Speed up the rate at which balloons are generated.
    • Use glide to make the balloons move around.
    • Resize the balloons so they all have a different random size.
    • Make the balloons appear at the bottom and glide towards the top to seem like they are helium balloons being released.
    • Use change color effect to change the colours of the balloons.
      • By using a random value, you can make each balloon be a different colour.

 

 

Here is an example that students came up with in class:

 

Note: We delete the clone at the end to make sure there aren’t too many balloons for Scratch to deal with as this can cause a crash.