Learning Goals 3 min
By the end of this lesson you will be able to:
- Explain that 1 step = 1 pixel on the Scratch Stage.
- Predict where the cat lands after a move (N) steps block runs.
- Build two scripts — one with a single big move, one with many small moves — and spot the difference on the Stage.
Warm-Up 7 min
You already know move (10) steps. Today we dig deeper — what is a "step", and what changes when the number gets bigger or smaller?
Quick-fire puzzle
Wei Jie built this stack and clicked the green flag. The cat started at x = 0. Where did it end up?
when flag clicked
move (60) steps
move (60) steps
move (60) steps
move (60) steps
Reveal the answer
The cat ended at x = 240 — the right edge. Each move adds 60 pixels. 4 × 60 = 240. The Stage is 480 wide and the cat began at the centre, so 240 to the right lands it right on the edge.
Notice — four moves in a row look like one instant jump on the screen. Scratch runs blocks too fast for your eyes to catch the in-between steps.
New Concept — what a "step" really is 15 min
A "step" in Scratch is not a footstep. It is one tiny dot of light on the screen — a pixel. When you write move (10) steps, the cat slides 10 pixels forward.
The block we are studying today
| Block | Category | What it does |
|---|---|---|
| move (10) steps | Motion | Slides the sprite forward by N pixels in its current direction. |
How big is one step?
The Stage is 480 pixels wide and 360 pixels tall. So:
- 1 step = a tiny nudge. You almost can't see it.
- 10 steps = a small slide. Easy to spot.
- 240 steps = half the Stage. Centre to one edge.
- 480 steps = the full Stage. Edge to edge.
Changing the number
You click on the white circle inside the move block to type any number you like — positive, negative, or zero.
- move (50) steps — slide 50 pixels forward.
- move (-50) steps — slide 50 pixels backward. A negative number reverses the move.
- move (0) steps — do nothing. Sometimes useful, mostly silly.
One big move vs many small moves
Imagine two paths from the centre to the right edge:
- One big move — move (240) steps. The cat teleports to the edge in a single instant.
- Many small moves — twenty-four copies of move (10) steps. The cat still teleports to the edge, because Scratch runs them all so fast.
To the human eye, they look identical. The difference will matter later when we add wait (1) seconds between the small moves — then you'll actually see the cat walking. That's a job for SCR-L01-18.
Why it matters
Every animated game, every walking sprite, every smooth slide on the Stage is built from the move block plus a way to slow it down. Today we master the block. Soon we'll add the pause.
Worked Example — Faiz's Cat slides across 15 min
We'll build the same end result in two different ways and compare. Open Scratch in a new tab.
Step 1 — Reset the cat
Click the cat in the Sprite list. In Sprite Properties, set x = -200, y = 0, Direction = 90. The cat now sits on the left side, facing right.
Step 2 — Build the BIG move
Drag when ⚑ clicked from Events. Drag move (10) steps from Motion. Snap them together. Click the white circle in the move block. Type 400. Press Enter.
when flag clicked
move (400) steps
Click the green flag. The cat zooms from the left side to the right side in an instant.
Step 3 — Reset the cat again
In Sprite Properties, set x back to -200. The cat returns to the left.
Step 4 — Build the MANY-small-moves version
Delete the move (400) steps block. Right-click it and choose "Delete Block", or drag it back to the Blocks Panel. Now snap eight move (10) steps blocks below the hat. Change each one to 50.
when flag clicked
move (50) steps
move (50) steps
move (50) steps
move (50) steps
move (50) steps
move (50) steps
move (50) steps
move (50) steps
Step 5 — Click the green flag
The cat zooms from x = -200 to x = 200 again. To your eyes, it looks identical to Version A.
What changed: two completely different scripts, same visible result. The cat ends up in the same place. Scratch runs the eight small moves so fast that your eyes can't catch the gaps.
Step 6 — A real difference
Try this version. Change just one middle block to a much larger number.
when flag clicked
move (50) steps
move (50) steps
move (50) steps
move (200) steps
move (50) steps
All three versions land the cat in the same spot. Distance is just the sum of every move block's number.
Try It Yourself — three small builds 12 min
Goal: Send the cat backwards. Reset x to 0. Build this stack, click the flag — where does the cat go?
when flag clicked
move (-100) steps
Think: A negative number flips the direction. The cat slides 100 pixels backward — to the left. Check Sprite Properties: x should now be -100.
Goal: Make the cat hop. Reset x to -200. Build this stack, click the flag once. Count where each block leaves the cat.
when flag clicked
move (100) steps
move (100) steps
move (100) steps
move (100) steps
Think: The cat steps from -200 → -100 → 0 → 100 → 200. Four moves of 100. The Stage looks like a single zoom, but the math is four jumps.
Goal: Land the cat on a target. Aisyah's plan: start the cat at x = -150. End the cat at x = +90. Build a stack of exactly three move blocks (any numbers) so that the total is 240 pixels forward.
when flag clicked
move (80) steps
move (80) steps
move (80) steps
Think: 80 + 80 + 80 = 240. Could you also do 100 + 100 + 40? Or 200 + 30 + 10? Yes — any three numbers that add to 240 work.
Mini-Challenge — back to the centre 5 min
"Send the cat home with two clicks"
Set the cat's starting x to -200. Build one script. After clicking the green flag twice, the cat must end up at the very centre of the Stage (x = 0).
You may also use a say [Hello!] for (2) seconds block (from SCR-L01-01) if you'd like the cat to celebrate.
It works if:
- The cat starts at x =
-200. - One click moves the cat halfway. A second click moves it the rest of the way.
- After click two, the cat sits at the centre (x =
0).
Reveal one valid solution
The total distance is 200 pixels. Each click must move 100 pixels.
when flag clicked
move (100) steps
Click 1: -200 → -100. Click 2: -100 → 0. The cat is home. Add a say [Bagus!] for (2) seconds block to make the cat cheer when it arrives.
Recap 2 min
One step is one pixel. The Stage is 480 wide and 360 tall, so 240 steps takes you from centre to either side. Negative numbers reverse the move. The cat's final position is just the sum of every move block's number. Many small moves and one big move look the same — until we add waits later.
- Step
- One pixel of distance on the Stage. move (10) steps slides the sprite 10 pixels forward.
- Pixel
- One tiny dot on the screen. The Stage is 480 pixels wide.
- Negative move
- A move block with a minus number, like move (-50) steps. The sprite slides backward.
- Forward
- The direction the sprite is facing. Default = 90 (right). Change Direction in Sprite Properties to flip "forward".
Homework 1 min
The 360-step trip. Build a Scratch project with one cat. Set the cat's starting x to -180. Use at least three move blocks (in one stack) that add up to exactly 360 steps. Click the green flag once. The cat should land at x = +180.
- Open Scratch (web or desktop).
- Reset Sprite Properties: x =
-180, y =0, Direction =90. - Build a stack that starts with when ⚑ clicked and has three or more move (10) steps blocks adding to 360.
- Click the green flag. Check Sprite Properties — x should read
180. - Take a screenshot of your Script Area and a screenshot of the Stage after the click.
Bring back next class:
- Both screenshots.
- Your written list of the three (or more) move numbers you chose, and the total to prove they add to 360.
Heads up for next class: SCR-L01-08 introduces two new Motion blocks — turning clockwise and turning counter-clockwise. You'll make the cat spin in place.