If / Else

The idea

Think of 'if/else' like a fork in a hiking trail with a sign: 'if it's raining, take the covered path; else, take the sunny one.' You always end up walking exactly one path, decided entirely by the condition on the sign.

What it actually is

'if <condition> then' is a C-shaped block that only runs the blocks inside it when a condition (a hexagon-shaped true/false check, like 'touching edge?') is true - otherwise it skips them entirely. 'if <condition> then / else' adds a second mouth that runs instead, whenever the condition is false.

How you write it

if <condition> then
  [runs only if true]
else
  [runs only if false]

A worked example

when 🏳️ clicked
if <touching edge?> then
  turn ↻ 180 degrees
else
  move 10 steps

Every time this checks, the sprite either turns around (if it's touching the edge of the Stage) OR moves forward (if it isn't) - never both, and never neither. Only one of the two mouths ever runs, decided by the hexagon condition.

Mistakes children actually make

Mistake 1: leaving the hexagon slot empty. An if block needs a true/false check dropped in there, or it has nothing to decide with. Mistake 2: dropping a number or text block into the hexagon slot instead. That slot only fits hexagon-shaped blocks - the ones that answer yes or no.

Then they try it

In the app this lesson continues with the animated explanation, spoken aloud, and then the practice: Use an if/else block so your sprite does one thing when a condition is true and something different when it's false. The editor runs your child’s real code and checks the result, with their coding buddy reacting to what they wrote.