Instructor Notes — Week 3

Theme: Conditionals (if / else)
Focus Concept: Decisions & basic logic
Mini-Project: Rock–Paper–Scissors (micro:bit chooses at random)

Learning Objectives

Participants understand that computers make decisions using conditionals (if … else).
Participants can predict, run, investigate, modify, and make programs using PRIMM.
Participants relate randomness, probability, and fairness to simple programs (coin toss; RPS).
Participants build a program that uses an if / else-if / else chain to choose Rock/Paper/Scissors.

Show this on the projector (don’t run it yet): Simple Coin Flipper

Prompt participants:

Draw the decision flow on the board: IF coin = 0 → “H” ELSE → “T”.
Discussion prompts:
- What happens if we change to pick random 1 to 2 but keep if coin = 0?
- What happens if we remove the else?
- Why is a coin toss considered fair?

Quick tweaks (5–7 min):

Transition: “Coin toss is a 2-way decision. Rock–Paper–Scissors has three choices, so we’ll use an if / else-if / else chain.”

Suggested build:

Event: on shake
Input: accelerometer
Process: set hand = pick random 0 to 2 Decide:
- if hand = 0 → show Rock icon
- else if hand = 1 → show Paper icon
- else → show Scissors icon
Output: LED display

Participants then play their hand with real gestures, comparing to the micro:bit’s choice. Extension: add second output (sounds) for R / P / S

Probability = how likely something is. Coin toss → 1 out of 2 (50%).
Chance = everyday word for probability.
Fairness = all outcomes equally likely.
In code, pick random makes games fair if we test all outcomes correctly.
Mini-activity: run coin toss 20 times, tally class results — close to 50/50 but not exact.

Conditional — an instruction that checks a condition and chooses what to do (if/else).
Logic — rules in decisions (later: AND/OR/NOT).
Random — an unpredictable value chosen by the computer.
Variable — a named box of memory that can change.
Fairness / Probability — equal chance of outcomes.