Fun with logic

Steps to listen to the Prime Minister's address on the radio:

1. Make sure the radio set is available and in working condition.
2. Connect the radio to a power source (insert batteries or plug in).
3. Switch ON the radio.
4. Tune the radio to the correct frequency/channel that broadcasts the Prime Minister's address (e.g., All India Radio).
5. Adjust the volume to a comfortable level.
6. Listen to the Prime Minister's address.

If you interchange any of the steps — for example, if you try to tune the radio before switching it ON, or adjust the volume before tuning to the correct channel — you will NOT get the desired result. The radio may not function correctly, or you may end up on the wrong channel and miss the address.

Conclusion: The sequence of instructions is extremely important. Each step must be performed in the correct order to achieve the desired output.

Given: We need to make the cat sprite trace specific paths in Scratch.

Concept Used: Motion blocks in Scratch — 'move ( ) steps', 'turn ( ) degrees', 'pen down', 'pen up'.

Script for a Square/Rectangular Path:

Step 1: Use the 'pen down' block to start drawing.
Step 2: Repeat the following 4 times (using a 'repeat 4' block):
- Move 100 steps
- Turn 90 degrees (right)
Step 3: Use the 'pen up' block to stop drawing.

Scratch blocks sequence:
```
when [Green Flag] clicked
pen down
repeat (4)
move (100) steps
turn right (90) degrees
end
pen up
```

Script for a Triangular Path:

Step 1: Use the 'pen down' block.
Step 2: Repeat the following 3 times (using a 'repeat 3' block):
- Move 100 steps
- Turn 120 degrees (right)
Step 3: Use the 'pen up' block.

Scratch blocks sequence:
```
when [Green Flag] clicked
pen down
repeat (3)
move (100) steps
turn right (120) degrees
end
pen up
```

Note: The exact number of steps and degrees may be adjusted based on the size of the path shown in the figures. For a rectangle, use different step values for horizontal and vertical sides (e.g., 150 steps and 100 steps alternately with 90-degree turns).

Steps to create the animation:

Step 1: Open Scratch (online at scratch.mit.edu or offline editor).
Step 2: Delete the default cat sprite.
Step 3: Add letter sprites from the Scratch sprite library for each letter of your name. For example, for the name 'AMIT', add sprites for A, M, I, T.
Step 4: Position each letter sprite at a starting position (e.g., off-screen or at the bottom of the stage).
Step 5: For each letter sprite, write a script:
- When Green Flag clicked
- Set initial position (e.g., go to x: ___ y: -180)
- Glide to the final position (e.g., glide 1 secs to x: ___ y: 0)
- Add a 'wait' block between letters so they appear one by one.
Step 6: Optionally add a sound block (e.g., 'play sound pop') for each letter.
Step 7: Click the Green Flag to run the animation.
Step 8: Click the full-screen icon to run in full screen mode.

Answers to the questions:

1. How many sprites did you add?
Answer: The number of sprites added equals the number of letters in your name. For example, for the name 'AMIT', 4 sprites were added (one for each letter: A, M, I, T).

2. Did you add costume for any of the sprite?
Answer: Yes, costumes can be added to letter sprites to change their appearance (e.g., change colour or style) to make the animation more attractive.

3. Did you add sound?
Answer: Yes, a sound (such as 'pop' or any music from the Scratch sound library) was added to play when each letter appears.

4. Did you run the script in full screen mode?
Answer: Yes, the script was run in full screen mode by clicking the full-screen icon at the top-right corner of the Scratch stage.

Given: We need to draw the alphabets A, E, F, H, M, W, Y, Z using Scratch.

Concept Used: Pen blocks (pen down, pen up), Motion blocks (move steps, turn degrees, go to x y), and the concept of breaking each alphabet into straight-line segments.

General Approach:

Step 1: Open Scratch and select the cat sprite (or any sprite).
Step 2: Add the Pen extension from the Extensions menu.
Step 3: Use 'go to x: ( ) y: ( )' to position the sprite at the starting point of each letter.
Step 4: Use 'pen down' to start drawing.
Step 5: Use 'move ( ) steps' and 'turn ( ) degrees' to trace each line segment of the alphabet.
Step 6: Use 'pen up' when you need to lift the pen (e.g., to draw the crossbar of 'A' or 'H' separately).
Step 7: Use 'set pen color' and 'set pen size' for better visibility.

Example — Drawing the letter 'A':
- Go to x: -20, y: -60 (bottom-left of A)
- Pen down
- Go to x: 0, y: 60 (top centre — left diagonal)
- Go to x: 20, y: -60 (bottom-right — right diagonal)
- Pen up
- Go to x: -10, y: 0 (left point of crossbar)
- Pen down
- Go to x: 10, y: 0 (right point of crossbar)
- Pen up

Similarly, each alphabet is drawn by identifying its line segments and programming the sprite to trace them using pen down/up and move/turn or go-to-x-y blocks.

Note: All these alphabets (A, E, F, H, M, W, Y, Z) are made entirely of straight lines, making them easier to draw in Scratch using directional movement and pen blocks.

Given: We need to draw geometric figures in Scratch as shown in the images.

Note: The exact figures are in images that cannot be fully viewed. Based on typical NCERT ICT Class 9 exercises, the figures are likely geometric shapes such as a triangle, a star, or composite shapes. The general method is described below.

Concept Used: Pen extension blocks, Motion blocks, Repeat loops.

General Steps:

Step 1: Open Scratch and enable the Pen extension.
Step 2: Set pen size and pen colour as desired.
Step 3: Position the sprite at the starting point using 'go to x: ( ) y: ( )'.
Step 4: Use 'pen down' to begin drawing.

Example — Drawing a Star (5-pointed):
```
when [Green Flag] clicked
pen down
repeat (5)
move (100) steps
turn right (144) degrees
end
pen up
```

Example — Drawing a Triangle inside a Rectangle:
- First draw a rectangle using repeat 2 { move 150, turn 90, move 100, turn 90 }
- Then lift pen, reposition, and draw a triangle using repeat 3 { move 100, turn 120 }

Step 5: Click the Green Flag to run and verify the figure.
Step 6: Adjust step values and angles as needed to match the required figure.

Key Formula: For a regular polygon with $n$ sides, the turning angle at each vertex $= \frac{360°}{n}$.

Given: We need to create three different animated stories in Scratch.

Concept Used: Sprites, Backdrops, Costumes, Motion blocks, Looks blocks (say/think), Sound blocks, Control blocks.

--- Part (a): A jungle where a lioness is giving safety tips to her cubs ---

Step 1: Open Scratch. Set the backdrop to 'Forest' or 'Jungle' from the backdrop library.
Step 2: Add a Lion sprite (lioness) from the sprite library or upload a custom sprite.
Step 3: Add 1–2 smaller lion/cat sprites to represent the cubs.
Step 4: Position the lioness at the centre and the cubs nearby.
Step 5: Write a script for the lioness sprite:
- When Green Flag clicked
- Say 'Always stay together in the jungle!' for 3 seconds
- Say 'Never go near the river alone.' for 3 seconds
- Say 'Run fast if you sense danger!' for 3 seconds
Step 6: Write a script for the cub sprites to nod (switch costumes) while the lioness speaks.
Step 7: Add jungle sounds from the sound library.
Step 8: Click Green Flag to run the animation.

--- Part (b): A spacecraft moving in space ---

Step 1: Set the backdrop to 'Stars' or 'Space' from the backdrop library.
Step 2: Add a Spaceship/Rocketship sprite from the sprite library.
Step 3: Write a script for the spacecraft:
- When Green Flag clicked
- Go to x: -200, y: 0
- Glide 3 secs to x: 200, y: 50 (moving across the screen)
- Or use: forever { move 5 steps, if on edge bounce }
Step 4: Add star sprites in the background that twinkle (switch costumes in a loop).
Step 5: Add a space/rocket sound.
Step 6: Click Green Flag to run.

--- Part (c): A dance performance on stage by a fairy ---

Step 1: Set the backdrop to 'Theater' or 'Stage' from the backdrop library.
Step 2: Add a Fairy or Ballerina sprite from the sprite library.
Step 3: Write a script for the fairy:
- When Green Flag clicked
- Play a dance music sound (loop)
- Forever:
* Switch to next costume (to animate dancing)
* Wait 0.3 seconds
* Move 10 steps
* If on edge, bounce
Step 4: Add spotlight effects using the stage backdrop or additional sprites.
Step 5: Click Green Flag to run the animation.

Conclusion: All three animations use the core Scratch concepts of sprites, backdrops, motion, looks (say blocks and costume changes), and sound to create engaging animated stories.

Given: We need to identify whether each statement about Scratch is True or False.

Concept: Knowledge of Scratch programming environment.

a. 'You can create animated stories with imaginary characters by Scratch.'
Answer: TRUE (T)
Reason: Scratch allows users to create animated stories using any kind of characters — real or imaginary — by using sprites, backdrops, and scripts.

b. 'Animations in Scratch can be created online only.'
Answer: FALSE (F)
Reason: Scratch can be used both online (at scratch.mit.edu) and offline using the Scratch Desktop (offline editor) that can be downloaded and installed on a computer.

c. 'By using Scratch we can create static shapes as well as animated stories using various sprites, instructions and tools.'
Answer: TRUE (T)
Reason: Scratch supports both static drawing (using Pen extension to draw shapes) and dynamic animations (using motion, looks, and control blocks with sprites).

d. 'Each object on the Scratch window is called a sprite.'
Answer: TRUE (T)
Reason: In Scratch, every character or object that appears on the stage (the display area) is called a sprite. Sprites can be animals, people, objects, letters, etc.

e. 'Scratch has an inbuilt library of sprites.'
Answer: TRUE (T)
Reason: Scratch comes with a built-in sprite library containing a wide variety of ready-made sprites (animals, people, fantasy characters, objects, letters, etc.) that users can directly add to their projects.

Summary Table:
| Statement | Answer |
|-----------|--------|
| a | True |
| b | False |
| c | True |
| d | True |
| e | True |