Learning Goals 3 min
By the end of this lesson you will be able to:
- Find the Sound category and play a sprite’s built-in sound.
- Explain the difference between
start sound [Meow v]andplay sound [Meow v] until done. - Choose the right one for a given job.
Warm-Up 7 min
New arc, new project. Start fresh and choose a busy street backdrop — this is your pasar pagi. Everything you have built so far has been completely silent, which for a market is a strange thing to be.
Quick-fire puzzle
Hafiz built these two scripts on two sprites. Both use a two-second sound. One cat moved straight away; the other stood still for two seconds first. Which was which?
when flag clicked
start sound [Meow v]
move (100) steps
when flag clicked
play sound [Meow v] until done
move (100) steps
Reveal the answer
The first one moved immediately. start sound [Meow v] sets the sound going and carries straight on to the next block, so the meow plays while the cat walks.
The second waited. play sound [Meow v] until done holds the script until the sound finishes, so nothing else happens for two seconds.
New Concept — sound that waits, and sound that does not 15 min
You have met this shape before. The plain say block puts a bubble up and moves on; the timed one holds the script. Sound has exactly the same pair, for exactly the same reasons.
Blocks reference
| Block | Category | What it does |
|---|---|---|
start sound [Meow v] | Sound | Starts the sound and moves straight on. The sound keeps playing underneath. |
play sound [Meow v] until done | Sound | Starts the sound and holds the script until it finishes. |
Which one, when?
| What you want | Which block |
|---|---|
| A noise while something else happens | start sound [Meow v] |
| A line of speech the next action must wait for | play sound [Meow v] until done |
| Several sounds layered on top of each other | start sound [Meow v] |
| Sounds that must play one after another | play sound [Meow v] until done |
Every sprite arrives with a sound
Click a sprite and open the Sounds tab, next to Costumes. The cat has a Meow already. Most library sprites come with something, and the dropdown in a sound block lists whatever the selected sprite owns.
That is worth remembering: like costumes, sounds belong to sprites. The cat cannot play Abby’s sound unless you add it to the cat too.
Sounds can overlap
Two start-sound blocks running close together play together. That is how a market gets its texture — several noises at once, none of them waiting politely for the others.
Why it matters
Sound is the fastest way to make a scene feel like a place. A silent market is a picture; add three noises and it becomes somewhere you could stand.
Worked Example — the market wakes up 15 min
We use both blocks in the same script, in the places where each is genuinely the right one.
Step 1 — Find the Sounds tab
Select the cat and click Sounds, next to Costumes. There is one sound: Meow. Click the play triangle to hear it.
Step 2 — Play it the waiting way
Back on Code, open the pink Sound category and build this.
when flag clicked
play sound [Meow v] until done
move (150) steps
Step 3 — Play it the other way
Swap the block for start sound [Meow v] and run it again.
when flag clicked
start sound [Meow v]
move (150) steps
Step 4 — Decide which is right
For a cat wandering through a market, the second is obviously better — a real animal does not stop dead to make a noise. But if the meow were a greeting the stallholder answers, you would want the first, so the reply does not arrive early.
Step 5 — Add a walk that lasts
Give the cat a proper walk so the overlap is easy to hear.
when flag clicked
go to x: (-160) y: (-40)
start sound [Meow v]
repeat (6)
next costume
move (40) steps
wait (0.2) seconds
end
Step 6 — Layer a second sound
Select the stallholder, add a sound to that sprite from the Sounds library, and give her a script that starts it at the same moment.
when flag clicked
start sound [Pop v]
wait (1) seconds
start sound [Pop v]
Step 7 — Try it with until-done instead
Change both of the stallholder’s blocks to the waiting version. The sounds now queue up neatly one after another, which sounds tidy and completely unlike a market.
Real places are noisy because sounds overlap. That is the argument for start-sound being your default here.
What changed: your project has a soundtrack, and you know which block to reach for depending on whether the sound is the action or the background.
The full assembled stack (your reference)
when flag clicked
go to x: (-160) y: (-40)
start sound [Meow v]
repeat (6)
next costume
move (40) steps
wait (0.2) seconds
end
Try It Yourself — three small builds 12 min
Goal: Make a key press produce a sound, so you can play the market like an instrument.
when [space v] key pressed
start sound [Meow v]
Think: press space rapidly several times. Because start-sound does not wait, the meows pile up on top of each other. Try it with until-done and they queue instead.
Goal: Build a call and response — one sprite makes a sound, and a second answers only after the first has finished.
when flag clicked
play sound [Meow v] until done
when flag clicked
wait (2) seconds
start sound [Pop v]
Think: the second sprite cannot hear the first, so its wait has to be at least as long as the first sound. Measure the meow by ear before you choose the number.
Mini-mission: three layers of market. Build a soundscape with three different sounds happening at once, so a listener with their eyes shut can tell it is a busy place.
It works if: a classmate with their eyes closed can tell you there is more than one thing making noise, and that it sounds like a place rather than a list. Keep each stack under 8 blocks.
Think: which of the two sound blocks lets things overlap, and what happens to your soundscape if you use the other one by mistake?
Mini-Challenge — the right block for the noise 5 min
“One scene, both blocks”
Build a short market scene that genuinely needs both sound blocks — one moment where the sound is the action, and one where it is only background.
It works if:
- One flag click plays the whole scene.
- One sound holds the script up because the next thing must wait for it.
- One sound plays underneath something else happening.
- You can explain why swapping the two blocks over would spoil it.
Reveal one valid solution (teacher)
when flag clicked
go to x: (-160) y: (-40)
play sound [Meow v] until done
say [Excuse me!] for (2) seconds
start sound [Meow v]
repeat (5)
move (50) steps
wait (0.2) seconds
end
The first meow is a call that the speech answers, so it must finish first. The second is the cat wandering off, so it should overlap. Pupils who use until-done for both get a cat that stands frozen listening to itself.
Recap 2 min
Sound comes with the same pair of blocks as speech. start sound [Meow v] sets a noise going and carries on, so sounds can overlap and run underneath other actions. play sound [Meow v] until done holds the script until the sound has finished, which is what you want when the next thing must not arrive early. Sounds belong to sprites, just like costumes do.
- start sound
- A Sound block that starts a noise and moves straight on. Sounds can overlap.
- play sound until done
- A Sound block that holds the script until the noise has finished.
- Sounds tab
- Next to Costumes. Lists the sounds the selected sprite owns.
- Soundscape
- Several overlapping sounds that together suggest a place.
Homework 1 min
Listen to a real place. Find out what a soundscape is actually made of before you build one.
- Stand somewhere busy — a kitchen, a street, a shop — and shut your eyes for one minute.
- Write down every separate sound you hear, and roughly how often each one happens.
- Mark which ones overlap and which ones happen alone.
- Bring the list, and be ready to say which Scratch block each sound would need.
when flag clicked
start sound [Meow v]
repeat (6)
move (40) steps
wait (0.2) seconds
end
Bring back next class:
- Your list of sounds.
- Your answer to: “Which sounds on your list overlapped with others, and which would need the until-done block instead?”
Heads up for next class: SCR-L01-36 opens the Sound library, where there are hundreds of noises better suited to a market than Meow.