Session 15 — Make Your First Game

Duration: 60 min · Format: live online

What you'll learn: by the end, you can open Scratch, add a sprite, and use key-press events to make it move and react on the stage.

Soft skill focus — Problem-solving

Today you'll also grow Problem-solving. Making a sprite move is really a stack of small problems — add a sprite, pick an event, snap on a motion block — solved one at a time.

Try this: when your sprite won't move, don't fix everything at once — ask yourself "what is the very next small thing that needs to happen?" (usually: snap the event to the motion block), then check just that one thing.

Think about: What was one small step you had to get right before your sprite would move?

What you'll need

• Open Scratch in a browser and click Create — a blank project, ready to build. No install needed.
• Your sound turned on, so you can hear your sprite meow.
• A quick idea to aim for: a cat that walks left and right with the arrow keys and "meows" when you press the space bar.

Hook

Think about these questions:

• What is your favourite game, and what do you do in it — jump, run, shoot, collect?
• When you press a key or tap the screen, something happens. Who tells the game to do that?
• Could you be the person who decides what happens when a key is pressed?

Here's the big idea: today you become the boss of the game. You'll tell a character exactly what to do when you press a key — and you'll build it yourself in Scratch.

Teach — The stage, sprites, and blocks

Here are the parts of the Scratch screen:

• The stage is the big white area on the right — it's where the game happens, like a theatre stage.
• A sprite is a character or object that lives on the stage — the cat is a sprite. You can have many sprites.
• Blocks are the coloured puzzle pieces in the middle — you snap them together to give a sprite instructions.
• The sprite list (under the stage) shows every sprite in your project. Click a sprite to give it its own blocks.

Use this diagram to find your way around the Scratch screen — the blocks palette, the script area, and the stage:

Try it in Scratch: drag a move 10 steps block (blue, Motion) into the code area and click it. The cat scoots across the stage. Click it again — it keeps going.

⚠ Watch for the mix-up between "stage" and "sprite": it's easy to think the whole screen is the sprite. Remember: the cat is the sprite; the white area is the stage it stands on.

Quick question: if you want a second character in your game, what do you add — a new stage or a new sprite? (Answer: a new sprite.)

Teach — Events make things happen

A game has to wait for the player. In Scratch, the yellow Events blocks are the "listeners" — they wait for something to happen, then run the blocks under them.

Build this in Scratch:

• Drag out when [space] key pressed (yellow, Events).
• Snap play sound [Meow] (pink, Sound) underneath it.
• Press the space bar. The cat meows! The event listened, then ran the block.

Now add movement with events:

• Add when [right arrow] key pressed and snap change x by 10 under it (Motion).
• Add when [left arrow] key pressed and snap change x by -10 under it.
• Press the arrow keys. The cat slides left and right.

Key idea: an event block starts the action. Without an event, your blocks just sit there — nothing tells them when to run.

Try it: the change x by 10 block moves the cat right. What number would move it left? (Answer: a negative number, like -10.)

Activity

Now build it in your own Scratch project.

Build this, step by step:

1. Keep the cat sprite (or click the sprite icon to pick a different one).
2. Add when [right arrow] key pressed → change x by 10.
3. Add when [left arrow] key pressed → change x by -10.
4. Add when [up arrow] key pressed → change y by 10, and when [down arrow] key pressed → change y by -10.
5. Add when [space] key pressed → play sound [Meow] (or any sound).
6. Test all four arrows and the space bar.

If something's not working, check:

• Sprite won't move — usually the event block is not snapped to the motion block (there's a gap).
• You press keys but nothing happens — check the block is under the right key in the dropdown.
• The cat flies off the edge — that's fine! You'll learn to control it next session.

Tip: rename your project (top-left box) something like "My First Game."

Check yourself

Try these — answers are after the arrow.

1. What is the difference between a sprite and the stage? → A sprite is a character or object; the stage is the background area where sprites live and the game happens.
2. What kind of block do you need so a key press makes the cat move? → An event block, like when [right arrow] key pressed — it listens for the key, then runs the blocks under it.
3. To move the cat left, do you use change x by 10 or change x by -10? → change x by -10 — the negative number moves it left.

Wrap-up

• Finish this sentence: "An event block is like a…" (a listener / a helper that waits for the player).
• Try this at home — Add a Trick: add one new thing your sprite does when a key is pressed — say something with say [Hi!], change colour, or play a different sound. Bring it to Session 16.

Tips & extra challenges

• Watch out: it's easy to think "the blocks run in order, all by themselves." In Scratch, a stack of blocks does nothing until an event (or a click) starts it. Keep an eye on the yellow "hat" blocks.
• Want more? Try this: build a mini keyboard piano — add several when [key] pressed blocks, each playing a different sound (Scratch has drum and note sounds). Then make the sprite change costume on one key so it looks like it's moving its mouth or legs while a sound plays. Can you explain out loud which event triggers which action?

Vocabulary

Resources

• Scratch — free, in your browser, no install (main tool).
• Scratch Starter Cards — printable idea cards for quick projects.
• Scratch Tutorials — the built-in "Getting Started" walkthrough inside Scratch.
• Scratch Ideas page — starter guides and inspiration for young game-makers.

Practice set

Practise on your own. Answers are after the arrow.

1. Add a sprite and make it move right when you press the right arrow key. → Use when [right arrow] key pressed snapped to change x by 10. Test by pressing the key.
2. Make the same sprite move left, up, and down with the other three arrow keys. → Three more event blocks: left → change x by -10, up → change y by 10, down → change y by -10.
3. Make your sprite play a sound when you press the space bar. → when [space] key pressed → play sound [Meow] (or any sound from the Sound tab).
4. Change the "10" to a bigger number, like 50. What happens? → The sprite jumps a bigger distance each press — it moves faster/further across the stage.
5. Add a second sprite and give it its own key to move (for example, "d" to go right). → Click the sprite, add when [d] key pressed → change x by 10. Each sprite has its own blocks.
6. Make your sprite say "Ouch!" when it reaches the edge — for now, just make it say "Ouch!" on a key press. → when [key] pressed → say [Ouch!] for 1 seconds. (Real edge-detection comes in Session 17.)

Going deeper (optional)

• What do x and y really mean? Show the stage's hidden grid: x is left–right (across), y is up–down. Drag the sprite and watch the x and y numbers change in its info box. If x gets bigger, which way does the cat go? (Right.) This plants the idea of coordinates without any maths lecture — you see it move.
• move 10 steps vs change x by 10. Both can move a sprite. move goes in the direction the sprite is pointing, while change x always goes sideways. Turn the sprite with point in direction and watch how move now goes a different way. This previews steering, which makes games feel alive.

Common mistakes & fixes

If it's not working, check these common mix-ups:

• Mistake: blocks are placed near each other but not actually snapped, so nothing runs. → Fix: watch for the white shadow that appears when blocks are about to connect; drag until you see it, then drop. Wiggle the top block — the whole stack should move together.
• Mistake: the event block has the wrong key in the dropdown (e.g. set to "up" but you press "right"). → Fix: click the little dropdown arrow on the event block and pick the exact key you want.
• Mistake: adding motion blocks to the stage instead of a sprite. → Fix: click the sprite in the sprite list first; the stage can't move.
• Mistake: expecting the sprite to move when you click the green flag, but only key-press events were added. → Fix: the green flag runs when green flag clicked blocks; key-press blocks need the key to be pressed.
• Mistake: using set x to 10 and wondering why the sprite jumps to one spot every time. → Fix: set x puts it at an exact position; use change x to add movement each press.

What's next

Session 16 — Score & Loops: you'll add a score with a variable, use forever loops to keep the game running, and send messages between sprites with broadcasts.