Teacher Notes — Week 6

Theme: Game Loops, Timing & Score
Focus Concept: Using Loops and Variables to Control Game Mechanics
Mini-Project: Barrel Jumper — building the playable version

Learning Objectives

  • Pupils recall what a loop is and how it repeats code automatically.
  • Pupils understand how pause time controls game speed.
  • Pupils use a forever loop as a continuous game engine.
  • Pupils use variables to manage score and speed.
  • Pupils can explain how coordinates control sprite position.
  • Pupils can link speed and score to make the game harder over time.

Recap (≈10 min)

Review the starting point from Week 5:

  • We created sprites and basic movement with a single “jump” or “move” block.
  • This week we’ll make that movement continuous and turn it into a full mini-game.

On the board:

“A forever loop is the heartbeat of a game — it keeps running while we play.”

Ask:

“What do we need to make the game more challenging each time we score?”

Expected answers: Make it go faster, keep track of score, or stop when you crash.

Project — Barrel Jumper (≈65 min)

We build the playable game step-by-step, testing each change.

Step 1 — Setup

on start
    set jumper to create sprite at x: 0 y: 4
    set barrel to create sprite at x: 4 y: 4
    set score to 0
    set speed to 200

🟩 Instructor Notes

  • jumper = player; barrel = obstacle.
  • The x coordinate controls left–right, y controls up–down.
  • speed is the pause between movements — smaller = faster.

Step 2 — Jump Action

on button B pressed
    repeat 4 times
        jumper change y by -1
        pause (100) ms
    repeat 4 times
        jumper change y by +1
        pause (100) ms

🟩 Instructor Notes

  • Two identical loops: up then down.
  • Pause defines jump smoothness.
  • Try faster (50 ms) or slower (150 ms) jumps and compare.

💬 Ask: “What happens if you delete one of the repeat loops?”

Step 3 — Main Game Loop

forever
    barrel move by 1
    barrel if on edge, bounce
    pause (speed) ms

🟩 Instructor Notes

  • This forever loop is the game engine.
  • move by 1 slides the barrel each frame.
  • if on edge, bounce flips direction automatically.
  • Explain that smaller speed values make the game faster and harder.

💬 Maths link:
1000 ms ÷ 200 ms = ≈ 5 updates per second.
Reducing pause to 100 ms ≈ 10 updates per second.

Step 4 — Add Scoring & Difficulty

forever
    barrel move by 1
    barrel if on edge, bounce
    pause (speed) ms

    if jumper touching barrel then
        game over
        show string "Score:"
        show number score

    if barrel x = 0 then
        change score by 1
        change speed by -10

🟩 Instructor Notes

  • “Touching” checks for collision between sprites.
  • When touching → game over ends program.
  • Each left-edge pass adds 1 point and increases speed (harder).

💬 Maths connection:
Start speed = 200 ms → after 5 points: 200 − (5 × 10) = 150 ms.

Step 5 — Optional Extensions

Encourage confident participants to add:

  • Sound FX: play tone when score increases.
  • Limit speed: stop at 60 ms minimum.
  • Display score: show number at the end.
  • Random barrel start: for more variation.

Vocabulary Focus

| Term | Child-friendly Definition | |——|—————————| | Loop (forever) | Repeats code again and again while the game runs. | | Variable | A labelled box storing a value like score or speed. | | Increment | Increase a variable by a fixed amount. | | Coordinate (x/y) | A position on the LED grid (x = left/right, y = up/down). | | Condition | A test that decides what happens next. | | Speed / Delay | Pause time between updates; smaller = faster. |

Differentiation

  • New coders: build movement + basic loop.
  • Confident: add score and speed-up logic.
  • Stretch: experiment with sounds, speed limits, or randomisation.

Assessment

  • Can pupils explain what the forever loop does?
  • Can they show where score and speed are used?
  • Can they predict what happens when pause decreases?
  • Can they identify why placing set score to 0 inside the loop breaks the game?

Common Mistakes

  • Putting set score to 0 inside the forever loop (resets score).
  • Forgetting to wrap movement code inside the loop.
  • Making pause too small → game runs too fast.
  • Using wrong coordinate (> 4 or < 0) so sprites disappear.

Materials & Setup

  • BBC micro:bits + USB cables
  • Chromebooks with internet access
  • Optional: headphones / speakers for sound

Safety & Safeguarding

  • Keep cables tidy and volume sensible.
  • Encourage turn-taking and peer support.

Reflection (for leader)

  • Who could explain how speed affects difficulty?
  • Who debugged independently?
  • Who experimented with extra features?
  • Note pupils ready to mentor peers next session.

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