Story: Meera wants to make a short animation of a dancing fish for her school’s Science Day. Her teacher says, ‘You will need a computer language to tell the computer what to do, step by step.’ Meera wonders what a computer language is, and how people who are not expert coders can still build fun projects. Her teacher smiles and says, ‘There is a language made just for students like you, called Scratch.’

A program is a set of instructions given to the CPU, in a proper sequence, to complete a task. Programs are written in a computer language with a pre-defined Syntax. Syntax is the grammar of a computer language.

A computer language is an interface between a computer and human beings (the user). It is a set of words, symbols and codes that the computer can understand. It is used to write a computer program.

The process of writing a program is called programming. People who write these programs are called programmers. Computer languages are classified into two major categories: Low Level Language (LLL) and High Level Language (HLL).

A Low Level Language is a programming language that is machine-dependent. It is closer to machine code. A machine-dependent language runs only on a particular type of computer.

A High Level Language is a programming language that enables a programmer to write programs that are machine-independent. It is closer to human-readable language. The main advantage of high level languages over low level languages is that they are easier to read, write and maintain.

Scratch is a high-level, block-based visual programming language. It has a free programmable toolkit that lets you create your own games, animated stories and interactive art, and share your creations with others over the Internet. You drag and combine code blocks to make animations, stories, musical instruments and games.

To start Scratch, double-click the Scratch icon if there is a shortcut on the desktop. Or, click the Start button, scroll and find the letter S in the program list, then click on Scratch 3.

Features of Scratch

• Easy to understand and learn.
• Tools for creating interactive stories, games, art and more.
• Predefined blocks are snapped together to create the project.
• Its own paint editor and sound editor.

Components of the Scratch Window

• Sprite: an object or actor that we see on the Scratch stage. The orange ‘cat’ is the default sprite.
• Stage: the main working area to draw or perform the action. It shows the output of the program.
• Backdrop: the background of the stage.
• Blocks Palette: contains various predefined blocks used to perform different tasks. These blocks are used to create scripts in Scratch.
• Sprites Info Pane: shows all the details of the sprites and backdrops used in a project.
• Coding Area: the area where we pick and drop blocks from the Blocks Palette to create a script or program.
• Script: a collection of a number of stacked blocks. It is also called a program and gives instructions in the form of blocks.
• Go Button: the green flag used to run a Scratch program.
• Stop button: the red button used to stop the project from running.
• Menu bar: used to provide drop-down menus for common commands, such as opening and saving a file.
• Tabs: there are three tabs in the Scratch window, namely Code tab, Costumes tab and Sound tab.
• Code Tab: contains nine main block categories, namely Motion, Looks, Sound, Pen, Events, Control, Sensing, Operators and Variables, plus a My Blocks category. Each category contains blocks of a different colour.
• Costumes Tab: here, you can add and make changes in the appearance of sprites and backdrops.
• Sounds Tab: here, you can add and make changes in the sounds of sprites and backdrops.

Changing the Appearance of a Sprite

1. Click on the Costumes tab.
2. Click on the image of the sprite and drag the selection blue border to select the cat.
3. Click on Fill and Outline options to change the fill colour and outline colour of the cat sprite.

Choosing a Sprite from the Library

1. Click on the Choose a Sprite option to open the library.
2. Select a sprite you want to use. The selected sprite appears on the Stage.

Deleting a Sprite

1. Select the sprite in the Sprites Info Pane.
2. Click on the Delete icon on the top right corner of the sprite in the Sprites Info Pane.

Resizing the Sprite

1. Select it in the Sprites Info Pane.
2. Click inside the Size text box and type the number. The size of the sprite changes.

Choosing a Backdrop

A backdrop is the background of the stage. You can choose a backdrop from the Library.

1. Click on Choose a Backdrop button to open the library.
2. Select a backdrop you want to use. The selected backdrop is applied to the stage.

Blocks are codes or commands used to create programs in Scratch. These puzzle-shaped blocks connect to each other vertically, like a jigsaw puzzle. To use a block, simply select it and then drag it onto your Coding Area. To add multiple blocks to a script, drag new blocks into the location in the script where you want them to appear. You can add new blocks above or below existing blocks.

Motion Blocks

They are colour-coded dark blue and are used to control the sprite’s movement: its placement, direction, rotation and movement.

1. Click on the Motion block.
2. Drag the ‘move 10 steps’ block to the Coding Area.
3. Change the ’10’ to ’50’ by clicking in the block and typing 50.
4. Double-click on the block in the Script area to see your sprite move 50 pixels to the right (towards the face of the sprite).
5. To move the sprite backwards, change ’10’ to ‘-70’. This moves the sprite to the left (opposite to the direction the sprite faces).

More Motion Blocks: drag the ‘turn 15 degrees’ block below the ‘move’ block already in your script; it attaches itself automatically. Add more blocks, and double-click on them to play the animation and see your sprite move.

Events Blocks

They are colour-coded yellow and are used to sense events, which run the scripts: for example, when a sprite is pressed, a key is pressed, or the green flag is clicked. They are placed at the top of any script and control the starting of the script. The most common Events block is ‘when green flag clicked’. Once you drag this block to the top of your script, you no longer need to double-click your blocks: clicking the Go button (green flag) runs the whole script.

Control Blocks

They are colour-coded amber and are used to control the scripts. This is a very important category, because they are used to create loops, conditions and sequences in code, and can make a sprite repeat actions until a condition is met.

Sound Blocks

They are colour-coded dark pink and are used to control sound. These blocks control the playback and volume of the sound files you select. You can also record your own voice or download sounds from your computer.

Full Screen Mode, Saving and Exiting

Click on the Full Screen Control button on the top right corner to fill the whole screen. To exit presentation mode, press the Esc key or click the same button again.

To save your project, click on the File tab, select ‘Save to your computer’, choose the location where you want to save it, type the name of the project in the File Name box, and click Save.

To exit Scratch, close the Scratch window by clicking the Close button in the Title Bar. If you have an unsaved project, Scratch will ask you to save it. Clicking Leave closes the window and loses any unsaved changes; clicking Stay brings you back to the Scratch window.

Image prompt: Flat illustration of the default orange Scratch cat sprite standing on a plain Stage.

A sprite is an object or actor that we see on the Scratch stage.

Key idea: The default sprite in a new Scratch project is an orange cat.

Image prompt: Flat illustration of a Scratch Stage with a beach backdrop and the cat sprite standing on it.

The Stage is the main working area where the sprite performs the action.

Key idea: A backdrop is the background picture shown on the Stage.

Image prompt: Flat illustration of a row of colourful puzzle-shaped blocks of different colours stacked on top of each other.

The Blocks Palette holds ready-made, colour-coded blocks for different tasks.

Key idea: Blocks snap together vertically, like a jigsaw puzzle, to build a script.

Image prompt: Flat illustration of an Indian child in the Costumes tab, changing the fill colour of a cat sprite with a paint brush tool.

In the Costumes tab, you can change the fill and outline colour of a sprite.

Key idea: You click, select and drag the border to choose the part you want to colour.

Image prompt: Flat illustration of a child browsing a grid of animal and fantasy sprite pictures on a screen, about to click one.

The Sprite Library has many ready-made characters to choose from.

Key idea: Clicking ‘Choose a Sprite’ opens the library; selecting one adds it to the Stage.

Image prompt: Flat illustration of dark blue puzzle blocks labelled ‘move’ and ‘turn’ pushing a sprite across the stage, with motion lines.

Motion blocks are colour-coded dark blue.

Key idea: They control a sprite’s placement, direction and movement.

Image prompt: Flat illustration of a yellow block at the top of a script, with a green flag icon glowing above a child’s finger about to click it.

Events blocks are colour-coded yellow and sense events, such as the flag being clicked.

Key idea: An Events block always sits at the top of a script, to start it.

Image prompt: Flat illustration of amber ‘forever’ and ‘repeat’ blocks wrapped around other blocks like a loop, with a sprite bouncing repeatedly.

Control blocks are colour-coded amber and create loops, conditions and sequences.

Key idea: A loop like ‘forever’ makes a sprite repeat an action again and again.

Meera, a Class 5 student in Mumbai, wants to make a short animation of a dancing fish for her school’s Science Day project. Her teacher opens Scratch and shows her the default orange cat sprite sitting quietly on the Stage. ‘First, let’s choose a fish instead of the cat,’ says the teacher, clicking on the ‘Choose a Sprite’ option to open the Sprite Library. Meera scrolls through the pictures and picks a bright, colourful fish from the library. It appears on the Stage at once, taking the place of the cat, and Meera is now ready to start building her dancing script.

Questions

1. Which option did the teacher click to open the sprite library?
2. What is the name for the tool used to pick a ready-made character like the fish?
3. What was the sprite on the Stage before Meera chose the fish?
4. Where does the newly chosen sprite appear after it is selected?
5. Why might choosing a sprite from the library be easier than drawing one from scratch?

Arjun’s elder cousin, who studies engineering in Pune, tells him that she is learning a Low Level Language for one of her college subjects, and finds it very difficult because it is so close to machine code. Arjun remembers that Scratch, which he uses in his Class 5 computer lab, lets him build games and animations just by dragging and snapping together colourful blocks, without typing a single line of code. He wonders why his cousin’s language is so much harder to read and write than the simple, high-level language he uses at school.

Questions

1. What kind of language is Arjun’s cousin learning: Low Level or High Level?
2. What does machine-dependent mean for a Low Level Language?
3. What kind of language is Scratch?
4. Why is a High Level Language usually easier to learn than a Low Level Language?
5. Give one reason Scratch feels easier to Arjun than his cousin’s college language.

Priya, in a school near Thane, builds a script in Scratch with a ‘move 10 steps’ block and a ‘turn 15 degrees’ block snapped together in the Coding Area. But every time she wants to see her sprite move, she has to double-click the blocks, which feels slow and clumsy during her presentation. Her classmate Rohan looks at her script and tells her that she is missing one important yellow block at the very top. Priya finds it in the Events category, drags it above her other blocks, and now she can simply click the green Go button once to play her whole animation instantly, exactly like the other projects in her class.

Questions

1. Which category of block was Priya missing at the top of her script?
2. Name the exact block Priya most likely needed to add.
3. Which colour are Events blocks coded?
4. Which button can now run Priya’s whole script in one click?
5. Why do Events blocks need to be placed at the top of a script?

Rahul, from a school in Kalyan, wants to build a small game where his sprite keeps moving forward and bounces back whenever it touches the edge of the Stage, again and again, without him clicking the green flag every single time. He remembers from his computer class that one category of Scratch blocks, used to control scripts, can make a sprite repeat actions until a condition is met. He opens the Blocks Palette, finds the amber-coloured blocks, and drags a ‘forever’ block so that it wraps around his ‘move 10 steps’ and ‘if on edge, bounce’ blocks, before testing it by clicking the Go button.

Questions

1. Which block category does Rahul use to make his sprite repeat forever?
2. Which colour are these blocks coded?
3. Besides loops, what else can this category of blocks create in a script?
4. What shape are Scratch blocks, and how do they connect?
5. Why is a ‘forever’ block useful for Rahul’s bouncing sprite?

Diya, a Class 5 student in Borivali, has spent almost an hour building her first Scratch animation, with a sprite, a backdrop and several scripts she is proud of, and it is nearly time for her computer lab period to end. Her teacher reminds the whole class to save their work carefully before closing Scratch, so that nobody loses the project they have worked so hard on. Diya clicks on the File tab in the Menu bar, chooses ‘Save to your computer’, picks the class folder on the computer, types a suitable name for her project in the File Name box, and finally clicks the Save button.

Questions

1. Which tab did Diya click first to save her project?
2. Which option under that tab did she choose?
3. What two things does Diya need to decide before clicking Save?
4. What might happen if Diya closes Scratch without saving, and then clicks Leave?
5. What should Diya click instead of Leave if she is not sure her project is saved?