Session 1 — Welcome to Scratch

Duration: 60 min · Format: live online

Session goal: by the end, students can name the three main parts of the Scratch screen, snap blocks into a script, and run their first program — a sprite that moves and says hello when the green flag is clicked.

Soft skill focus — Curiosity

Today's human skill: Curiosity. Scratch is brand new, and the whole editor is full of colourful blocks just begging the question "what does this one do?"

• Build it in class: before you name the move and say blocks, let students drag a few blocks out and predict what each one does, then press the green flag to check. During the activity, when someone asks "what happens if I put 100 here?", say "great question — try it and tell us," rather than answering yourself.
• Reflection (wrap-up): ask "What is one block you want to figure out how to use next time?"

Before class — prep

• Open Scratch in a tab (signed in if you can, so you can save) and be ready to screen-share the editor.
• Have the two diagrams below open to share (the Scratch screen and the block families).
• If any student can't run Scratch, have the low-tech fallback (paper blocks) ready — see Teaching notes.

Hook

Ask the class (chat or unmute):

• "If you had a robot cat that did exactly what you told it — what's the first thing you'd make it do?"

Take three answers. Then reveal: "Today you become the boss of a cat on the screen. The cat only does what you tell it — and you tell it with blocks instead of typing. Let's give it its first orders."

Teach — The three parts of the Scratch screen

Share this diagram and point to each part as you name it:

Explain, slowly, pointing on your shared screen:

• 1 · The Blocks palette (left): a box of coloured command blocks — the "orders" you can give.
• 2 · The Script area (middle): where you drag blocks and snap them together to make a program.
• 3 · The Stage (right): where your sprite (the cat) actually does what the blocks say. The green flag ▶ above the stage means GO; the red stop sign means STOP.

The blocks come in colour-coded families. Share this and tell them they don't need to memorise it — just know that colour tells you what a block does.

Ask: "If I want my cat to move, which colour of block should I look for?" (Answer: blue — Motion.)

Teach — Snap blocks & press the green flag

Explain: a program is just blocks snapped together so they run top to bottom. Build this live on your shared screen while they watch — go slowly and name each block.

Build this together:

1. From Events (yellow), drag out when green flag clicked — this is a "hat" block; it starts the program.

2. From Motion (blue), snap move 10 steps under it. Watch the white shadow appear before you drop — that shadow means it will connect.

3. From Looks (purple), snap say [Hello!] for 2 seconds under that.

Now your script reads:

when green flag clicked
move 10 steps
say "Hello!" for 2 seconds

Press the green flag. The cat slides a little and a speech bubble pops up. Celebrate — that's a real program!

⚠ Watch for the #1 beginner mistake: blocks placed near each other but not actually snapped. If nothing runs, wiggle the top block — the whole stack should move together. If a block gets left behind, it wasn't connected.

Ask: "Which block made the cat talk? Which made it move?" (Say = Looks/purple; move = Motion/blue.)

Activity — Make your sprite move & talk

Students build their own first script. Demo the first step, then let them go and circulate.

1. Open a new project at Scratch.
2. Build the when green flag clicked → move 10 steps → say "Hi, I'm [your name]!" script. Press the green flag.
3. Make it yours: change the number in move to a big number (like 100) — what happens? Change the words in say. Add a second say block.
4. Extra: from Looks, add change color effect by 25 and run it a few times. What happens to the cat?

Circulate and ask: "Show me the block that starts your program. What did you change?"

Debrief: ask 2–3 students to share their screen and press their green flag for the class.

Check for understanding

Ask these aloud or in the chat. Answer key (for you):

1. What are the three main parts of the Scratch screen? → The Blocks palette, the Script area, and the Stage.
2. What does the green flag do? → It runs (starts) your program. The red button stops it.
3. A block does nothing when you run it. What's the most likely reason? → It isn't snapped to the script — connect it under the when green flag clicked stack.

Wrap-up + homework

• Ask one student to explain, in one sentence, what "snap blocks together" means.
• Homework — Teach the cat a trick: make the cat say two different things and move, then press the green flag. Screenshot it for your portfolio.

Teaching notes

• Correct this misconception: "the blocks run all by themselves." In Scratch, a stack does nothing until an event (like the green flag) starts it. Keep pointing at the yellow "hat" block.
• Fast finishers (extension): have them add a Sound block (play sound Meow) and a second say, then make a tiny "hello routine": move, meow, say two lines. Ask them to explain the order the blocks run in — top to bottom.
• Low-tech fallback: no devices? Print or draw paper blocks (a yellow "when flag clicked", a blue "move", a purple "say"). Students physically stack them on their desk and "run" them by reading top to bottom while a partner acts as the cat. The idea — ordered instructions — is the real lesson; the mouse is just the tool.

Vocabulary

Resources

• Scratch editor — where students build (free, in the browser).
• Scratch Starter Guide (PDF) — a one-page getting-started sheet.
• Scratch Ideas page — official tutorials and starter cards.

Practice set

Extra tasks to explore the Scratch screen and first blocks. Work them easy → hard, at lab time or for homework. Answers follow each arrow.

1. Name that part. Where do you drag blocks to snap them together? → The Script area (the big middle space).

2. Colour clue. You want your sprite to say something. Which colour block do you look for? → Purple — Looks.

3. Fix it (spot the bug). A student's move 10 steps block is sitting next to the when green flag clicked block, not under it, and nothing moves. What's wrong? → It isn't snapped underneath — drag it until the white shadow appears, then drop.

4. Predict. The script is when green flag clicked → move 100 steps. What happens when you press the flag? → The sprite jumps a long way across the stage (100 is a big step).

5. Make it (build task). Build a script so the cat says "Ready?" for 1 second, then moves 50 steps. → when green flag clicked → say "Ready?" for 1 seconds → move 50 steps.

6. Two orders (harder). Put these in the right order so the cat greets, then moves: move 20 steps, when green flag clicked, say "Hi!". → when green flag clicked (top) → say "Hi!" → move 20 steps. The hat block is always on top.

Going deeper (optional)

Optional — for a class that's snapped its first script and wants to know why Scratch works the way it does.

Why blocks instead of typing? Real code (like Python) is typed, and one wrong letter breaks it. Scratch removes the spelling problem so beginners can focus on the thinking: what order should the steps happen in? Point out that the shapes of the blocks are a clue — a "hat" block is rounded on top so nothing can snap above it, and command blocks have a bump and a notch so they only fit one way. The shapes are teaching you the grammar of programming without a single word of it.

Sprites each have their own scripts. Add a second sprite (click the cat icon at the bottom-right → choose one). Click it, and notice the script area is now empty — because scripts belong to the sprite you've selected. This is a big idea students will use all course: each character carries its own set of instructions.

Common mistakes & fixes

• Mistake: Blocks placed near each other but not snapped, so nothing runs. → Fix: drag until the white shadow appears, then drop; wiggle the top block to check the whole stack moves together.
• Mistake: Pressing keys or clicking the sprite and expecting it to run, when only a when green flag clicked was added. → Fix: press the green flag to run that script (other starts come in later sessions).
• Mistake: Adding motion blocks but the sprite "won't move" — it already ran off the edge. → Fix: drag the sprite back to the middle of the stage, or add go to x:0 y:0 to reset it.
• Mistake: Editing blocks on the Stage instead of a sprite. → Fix: click the sprite in the sprite list (bottom area) first — the stage can't move.

Next session

Session 2 — Make It Move: students meet the full family of Motion blocks — glide, turn, point — and make a sprite walk, spin and glide smoothly around the stage.