1, 2, 3, code ! - Cycle 3 activities - Step 2.9. Further study in Scratch

Summary

Here are several ideas to explore other functionalities in Scratch, such as giving students extra options for their personal projects.

Key ideas
(see Conceptual scenario)

"Machines"

  • The machines all around us simply follow orders (instructions).
  • By combining basic instructions, we can make them execute complex tasks.

"Algorithms"

  • An algorithm is a method used to resolve a problem.
  • A loop allows the same action to be repeated multiple times.
  • Certain loops, known as “infinite loops,” never stop.
  • Certain loops, known as “iterative loops,” are repeated a predefined number of times.

"Languages"

  • Scratch is a graphical programming environment that uses a simple language.
  • A program is the expression of an algorithm in a programming language.
  • Certain instructions are only executed when an event is triggered. This is known as event-driven programming.
  • Certain instructions are executed one after the other. This is known as sequential programming.
  • The execution of a program is reproducible (if neither the instructions nor the data to manipulate change, the program always gives the same result)

Equipment

For each student pair

  • A computer with Scratch and the program saved from the previous lesson

Duration

1 to 4 lessons

 

Foreword

During the previous lessons, students learned about the basic functionalities and concepts of Scratch:

  • Sprites
  • Stages
  • Instruction blocks
  • Motion
  • Looks
  • Events
  • Loop
  • Tests
  • Variables
  • Calculations and logical operators
  • Sensors

However, there are many functionalities that were not covered. Many are very simple and can enhance students' programs they do on their own: games, animated cards, interactive surveys, drawings, etc. We have provided a list below.

 

Costumes

Each sprite can have several "costumes" that correspond to its physical appearance. A new costume can be a slight variation of the previous costume (a different arm or leg position, etc.) or very different than other costumes.

To create a new costume, select the sprite you want to change and click the "Costumes" category. This new costume can be based on the old costume, an imported image or a drawing created by the user.

 

Here, the cat (default sprite in Scratch) has two costumes. You can change the costume while making it move forward, which makes it look like it is walking.

The two instructions to change costumes are available in the "Looks" category:

 

 

For the previous sequence, for example, you can ask the students to create a new costume for the rover to make it look "burned" or "broken" to be activated when the rover hits an obstacle.

 

Pen

Each sprite has a "pen" that leaves a line on the ground (the screen) when lowered. The pen's default position is raised and does not leave a line.

The instructions available from the green "Pen" category let you raise or lower the pen, change the thickness of the shade, thickness, color, etc. of the line.

This functionality means you can create such things as geometric shapes in Scratch.

 

Speech and questions/answers

Each sprite can display text on the screen ("Say" instruction in the "Looks" category). It can also interact with the user by asking questions ("Ask" instruction in the "Sensing" category). It waits for the user's response typed with the keyboard and saves it in a predefined variable called "answer." The answer, like any variable, can be manipulated by the program.

This small program, for example, greets the user by using their first name:

 

 

This one asks a question and congratulates the user if the answer is correct.

 

 

It is possible (and quite interesting) to use Scratch to ask the students to program quizzes or tests in different subjects.

 

Other ideas

Scratch offers even more possibilities and functionalities, but they may be too complex for elementary school students. For example:

  • Clones, which can be used to duplicate a sprite in as many copies as desired, each considered to be the same sprite as the original (they obey the same programs). For the project in this sequence, you might, for example, want to display a random number of plants and place them randomly around the stage. The clones are found in the "Control" category.
  • Custom blocks, which let the user create their own new instruction blocks. This can be very useful if you frequently re-use the same set of instructions. Rather than repeating them, grouping them in a custom block saves time, lightens the code and reduces errors.
  • Custom blocks are available from the indigo menu "More blocks" (create a new block).
  • Sounds: Using sounds can be very easy (each sprite can play a pre-recorded sound or a note with the pitch and volume adjusted), but it can quickly become cumbersome in a classroom setting.

 

 


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