Stage Coordinates: x and y

Learning Goals 3 min

By the end of this lesson you will be able to:

1. Name the four edges of the Stage: x = -240, x = +240, y = -180, y = +180.
2. Read any sprite's x position and y position from the Sprite Properties panel.
3. Drag the cat with your mouse to four named locations on the Stage and call out the coordinates each time.

Warm-Up 7 min

The cat can now walk and turn around the garden. Today we pause the action and study the map under the cat's paws — the Stage's coordinate grid — so we can name every flower bed by its exact (x, y).

Quick-fire puzzle

Priya set the cat's Direction to 90 and clicked the green flag. The cat started at x = -100, y = 50. Where did it end up?

when flag clicked
move (200) steps
        

New Concept — the Stage's coordinate map 15 min

The Stage is a giant grid, like the squared paper in your maths book — except it's stretched out and the centre is exactly in the middle. Every spot on the Stage has two numbers: an x (how far left or right) and a y (how far up or down).

The two numbers we read today

These are not blocks today — they're readouts. The Sprite Properties panel shows them all the time. As you drag the cat around the Stage with your mouse, watch the x and y numbers change in real time.

The map

Reading any spot on the map

To name a spot, write the x number first, then the y number, inside round brackets and separated by a comma. Examples:

• (0, 0) — the centre.
• (240, 0) — the right edge, middle height.
• (0, 180) — the top edge, middle width.
• (-100, 50) — a bit to the left, a bit above centre.
• (-240, -180) — the bottom-left corner.

Drag-and-read

Open Scratch. Click and hold on the cat on the Stage. Drag it slowly around. Watch the x and y fields in Sprite Properties — they update in real time as the cat moves. This is the easiest way to feel the coordinate grid: drag, read, repeat.

Why it matters

Every game built in Scratch uses coordinates. A target sprite at the top-right of the Stage. A score watcher in the top-left. A player that starts at the bottom and walks up. The map of x and y is the floor plan of your project.

Worked Example — map the cat's journey 15 min

Today's example is a treasure-hunt-style tour. We won't write a new block — we'll read the cat's position at four named stops along the Stage.

Step 1 — Reset

Click the cat in the Sprite list. In Sprite Properties, type x = 0, y = 0, Direction = 90. Cat sits dead centre.

Step 2 — Build the move block from last lesson

Drag when ⚑ clicked and move (100) steps. Snap them. Click the flag once. Cat is now at x = 100, y = 0. Read the values straight from Sprite Properties to check.

when flag clicked
move (100) steps
        

Step 3 — Drag the cat to the top-left corner

Don't use blocks for this step. Use your mouse: click and drag the cat to the top-left of the Stage. Aim for somewhere near the corner. Read Sprite Properties. The x should be near -200 (a big negative number). The y should be near 150 (a big positive number).

Write down what you read. For example: top-left corner ≈ (-205, 152). Different drags give slightly different answers — that's fine. The big idea: top-left = negative x, positive y.

Step 4 — Drag the cat to the bottom-right corner

Now drag the cat all the way to the bottom-right. Read Sprite Properties. The x is near +200, the y is near -150. Write it down: bottom-right ≈ (208, -148).

Step 5 — Drag the cat to the top edge, centre

Drag the cat straight up. Try to stop at the top edge with x near 0. You'll read something like top centre ≈ (0, 175). Notice: x didn't change because you only moved up-and-down. y did.

Step 6 — Drag the cat back to (0, 0)

Drag carefully toward the middle. Watch x and y count down together. When both show 0 (or very close), let go.

What changed: you didn't add a single new block — but you now understand the Stage as a map of numbered spots. Sprite Properties is your map-reader.

Your tour log

You visited four spots: centre, top-left, bottom-right, top centre. Write the coordinates in your notebook. We'll use them again in SCR-L01-10 — but with a block that teleports the cat to any (x, y) instead of dragging.

Try It Yourself — three small builds 12 min

when flag clicked
move (50) steps
          

when flag clicked
move (0) steps
          

when flag clicked
move (80) steps
          

Mini-Challenge — name that corner 5 min

"Four-corner tour"

Working only with the Sprite Properties panel (typing x and y values directly — no new blocks), park the cat at each of the four corners in turn. After each parking, write down the x and y values you typed.

It works if:

• The cat visits all four corners: top-left, top-right, bottom-left, bottom-right.
• For each corner, you write down a pair like (-240, 180).
• You can correctly say which quadrant uses positive y, which uses negative x, etc.

Recap 2 min

The Stage is a grid. Every spot has two numbers — x (left-right) and y (up-down). The centre is (0, 0). The corners are at (±240, ±180). You can read any sprite's x and y in the Sprite Properties panel and you can type them directly to park the sprite at any spot. Tomorrow we meet a Motion block that does the same thing in one go.

Coordinate

A pair of numbers (x, y) that names one spot on the Stage. Example: (100, -50).

x position

The left-right number. Ranges from -240 (left edge) to +240 (right edge). Zero is the middle.

y position

The up-down number. Ranges from -180 (bottom edge) to +180 (top edge). Zero is the middle.

Origin

The dead centre of the Stage. Always (0, 0).

Homework 1 min

The five-stop map. Visit five named spots on the Stage by typing values into Sprite Properties. Write down each pair of coordinates as you go.

1. Open Scratch (web or desktop). Click the cat in the Sprite list.
2. Type each pair into Sprite Properties (x first, y second), one at a time:
   • Stop 1 — Centre: x = 0, y = 0.
   • Stop 2 — Top edge: x = 0, y = 180.
   • Stop 3 — Right edge: x = 240, y = 0.
   • Stop 4 — A spot you choose, in the bottom-left quadrant (x must be negative, y must be negative).
   • Stop 5 — A spot you choose, in the top-right quadrant (x positive, y positive).
3. Take a screenshot of the Stage at Stops 4 and 5.

Bring back next class:

• Two screenshots (Stops 4 and 5).
• The five pairs of coordinates written in your notebook.
• Your written answer to: "Which corner of the Stage has the most negative x AND the most negative y?"

Heads up for next class: SCR-L01-10 introduces a new Motion block — go to x: (0) y: (0). The cat will teleport to any spot in one snap, no dragging needed.