Learning Goals 3 min
By the end of this lesson you will be able to:
- Tell the difference between turn ↻ (15) degrees and turn ↺ (15) degrees.
- Predict the cat's new direction after a turn block runs.
- Build a spinning cat — one click of the green flag makes the cat turn a full circle.
Warm-Up 7 min
Arc 1 taught the cat to stroll a measured straight distance. Today the cat learns to turn at the garden corners — two new blocks, both in the blue Motion category.
Quick-fire puzzle
Hafiz built this stack. The cat started facing right (Direction = 90). What direction does the cat face after one click of the flag?
when flag clicked
turn cw (90) degrees
Reveal the answer
The cat ends up facing down (Direction = 180). A clockwise turn of 90 from "right" lands on "down" — like a clock's hand going from 3 o'clock to 6 o'clock.
Check it yourself: open Sprite Properties after clicking. The Direction field should now read 180.
New Concept — clockwise and counter-clockwise turns 15 min
Think of the cat as a tiny compass needle. The needle has an arrow pointing somewhere. A turn block rotates the needle. Clockwise (↻) = same way a clock's hands move (right hand swings down). Counter-clockwise (↺) = the opposite way (left hand swings up).
The two new blocks
| Block | Category | What it does |
|---|---|---|
| turn ↻ (15) degrees | Motion | Spins the sprite N degrees clockwise (right). |
| turn ↺ (15) degrees | Motion | Spins the sprite N degrees counter-clockwise (left). |
How big is a turn?
Turns are measured in degrees. A full circle is 360 degrees. Here are the four most useful numbers:
- 90 degrees = a quarter turn. Right becomes down (clockwise) or up (counter-clockwise).
- 180 degrees = a half turn. The cat now faces the opposite way.
- 360 degrees = a full circle. The cat ends up facing exactly where it started.
- 15 degrees = a small tilt. The default number when you drag the block in.
Reading the dial in Sprite Properties
You met the Direction field in SCR-L01-02. After a turn block runs, the Direction value changes. You can watch it tick up or down as you click the flag — that's the same compass needle the cat carries with it.
Why it matters
Every walking, running, or flying sprite uses turn blocks. A racing car needs to corner. A bird needs to swoop. A dancer needs to spin. Once you can turn the cat, all of those are within reach.
Worked Example — make Aiman's Cat spin 15 min
Today we build a cat that spins in place. Open Scratch in a new tab.
Step 1 — Reset the cat
Click the cat in the Sprite list. In Sprite Properties, set x = 0, y = 0, Direction = 90. Cat sits at the centre, facing right.
Step 2 — Try a quarter turn
Drag when ⚑ clicked from Events. Drag turn ↻ (15) degrees from Motion (the one with the clockwise arrow). Snap them. Change 15 to 90.
when flag clicked
turn cw (90) degrees
Click the green flag. The cat tips over so its head points to the right edge of the Stage and its tail to the left — it is now facing down. Check Sprite Properties: Direction is now 180.
Step 3 — Click again
Click the flag again. The cat turns another 90 — now facing left. Direction reads -90. Click again, the cat faces up (Direction = 0). One more click brings it back to facing right.
Step 4 — Build a full-circle spin
Now we want a single click to spin the cat all the way around. We need 360 degrees of turning. Four 90s in a row will do it.
Reset Direction in Sprite Properties to 90. Then snap three more turn ↻ (15) degrees blocks under your first one. Change each one to 90.
when flag clicked
turn cw (90) degrees
turn cw (90) degrees
turn cw (90) degrees
turn cw (90) degrees
Step 5 — Click the green flag
The cat spins one full rotation. But it looks like nothing happened — because the cat went right back to where it started. Check Sprite Properties: Direction is back to 90. The four turns happened too fast to see.
What changed: the cat did spin — your eyes just couldn't catch it. Next lesson we'll add the Stage coordinates; later we'll add waits so you can actually see the spin.
Step 6 — A simpler full-circle version
You don't need four blocks to spin once. One block does it:
when flag clicked
turn cw (360) degrees
Try a half-spin instead — turn ↻ (180) degrees. The cat now faces left.
Try It Yourself — three small builds 12 min
Goal: Make the cat face up. Reset Direction to 90. Build this stack and click the flag.
when flag clicked
turn ccw (90) degrees
Think: Counter-clockwise from "right" (90) is "up" (0). Check Direction in Sprite Properties — it should now read 0.
Goal: Move and turn. Reset x = -100, y = 0, Direction = 90. Click the flag once.
when flag clicked
move (80) steps
turn cw (90) degrees
move (80) steps
Think: The cat slides right 80 steps, turns to face down, then slides "forward" again — but now forward is down. The cat lands below the centre. Check x and y in Sprite Properties.
Goal: Draw a square path. Reset x = -50, y = 50, Direction = 90. Click the flag once.
when flag clicked
move (100) steps
turn cw (90) degrees
move (100) steps
turn cw (90) degrees
move (100) steps
turn cw (90) degrees
move (100) steps
Think: Four moves and three turns trace a square shape on the Stage. (We need the fourth side to close the square — and that's coming in a later lesson with the Pen extension.) Watch the cat: it ends up back near where it started.
Mini-Challenge — spin in place 5 min
"The Spinning Cat"
Build a script that spins the cat in place when you click the green flag — but with a twist. Use both a turn block and a move block. The cat must end up exactly where it started, facing the same direction it started.
It works if:
- You click the green flag once.
- Your stack uses at least one turn block and at least one move block.
- After the script runs, Sprite Properties show the same x, y, and Direction as before.
Reveal one valid solution
Move forward by N, spin a half-circle (180), move forward by N again, spin another 180. The cat walks out and back, and ends facing its original direction.
when flag clicked
move (100) steps
turn cw (180) degrees
move (100) steps
turn cw (180) degrees
The cat steps right 100, flips to face left, steps back 100 (to the start), flips again to face right. Same start, same end. Combines today's turn blocks with last lesson's move idea — many small moves and turns adding up to "nowhere".
Recap 2 min
Two new blocks today. The clockwise turn rotates the cat the same way a clock's hands move. The counter-clockwise turn rotates the opposite way. Turns are measured in degrees — 90 = quarter, 180 = half, 360 = full circle. A turn changes the cat's Direction but never its x or y. Combine turns with moves to walk the cat anywhere.
- Clockwise (↻)
- The way a clock's hands move — top, then right, then down, then left. The "turn cw" block uses this direction.
- Counter-clockwise (↺)
- The opposite of clockwise. The "turn ccw" block uses this direction.
- Degree
- The unit of a turn. A full circle is 360 degrees. A quarter turn is 90 degrees.
- Direction
- The way a sprite is facing, shown in Sprite Properties. 0 = up, 90 = right, 180 = down, -90 = left.
Homework 1 min
The four-corner trip. Reset the cat to x = 0, y = 0, Direction = 90. Build a stack that walks the cat in a square-ish path: forward 80, turn 90 clockwise, forward 80, turn 90 clockwise, forward 80, turn 90 clockwise, forward 80. Click the flag once.
- Open Scratch (web or desktop).
- Reset Sprite Properties as above.
- Build the stack with four move blocks (each
80) and three turn blocks (each90clockwise). - Click the green flag. Read off the final x, y, and Direction from Sprite Properties.
- Take a screenshot of your Script Area and a screenshot of Sprite Properties after the run.
Bring back next class:
- Both screenshots.
- Your written answer to: "After the script finishes, what direction is the cat facing? Why isn't it facing right (90) like it started?"
Heads up for next class: SCR-L01-09 dives into Stage coordinates — the full map of x and y. You'll learn how to read any sprite's position from anywhere on the Stage.