For parents and teachers

What this is for, what it refuses to do, and how to get more out of it than screen time.

Answers are free now. Judgement is not.

Any explanation your child needs — why a fuse blows, how a cooker builds pressure — is one question away, and a machine will answer it better every year. What no machine can do for your child is notice that something is wrong.

Spotting the missing part, the piece that does not belong, the step in the wrong order — that is what engineers, doctors, mechanics and careful adults do all day.

School rarely teaches it, because it cannot be memorised or marked with an answer key. It is built only by meeting broken systems again and again, guessing, being wrong safely, and finding out why. That is the whole design of this app.

How a case works

1. A small, real system is described — a fan, a compost bin, a crowded bus door.
2. Something is wrong with it. Your child works out what.
3. They can run it anyway and watch the consequence unfold. This is the emotional core: feeling the failure before anyone explains it.
4. When they get it right, a technical note gives the real mechanism, plus the transferable lesson.

The note appears the moment the case is solved. We removed a step that used to make children type an explanation first — the note is the teaching, and it should never be rationed.

What we collect: nothing

Progress lives on your device. If you change phones, there is a backup you copy yourself — no cloud involved. Full privacy policy.

Money, and where it hides

Sixty-three of the ninety-nine cases are free forever, and that includes every case about road safety, first aid, kindness, money sense and staying safe online. Values are never behind a price. Only the deeper machine-and-mechanism packs cost anything, as one-time purchases.

Purchases sit behind a grown-up gate and are never shown to a child while they play. The strongest protection is not in our app though — it is in the Play Store itself: turn on "Require authentication for purchases" in your Play settings, which covers every app on the phone.

Getting more than screen time out of it

• Ask them to teach it back. "Explain that one to me" is worth more than the next case.
• Find the same fault in the house. The fridge pushed against the wall, the tap that drips, the bin that smells.
• Let them be wrong. The app is designed so being wrong costs nothing. Try to match that at the table.
• Use the Create tab. Building a mystery for someone else is a harder, better exercise than solving one.

Under six?

We do not make screen content for children under school age, and we explain exactly why — read the birth-to-five guide. What we offer for this age is on paper instead, which is what the evidence actually supports. All of it is free:

• High-contrast baby cards — shapes, nature, animals and birds, downloaded one card at a time. From birth, once they will hold a gaze.
• High-contrast patterns for newborns — stripes, checks and spirals rather than pictures, for the first six months.
• Spot the Snag, for ages 3–5 — find-the-fault cards a child who cannot yet read finds the gap in, and then draws back in with a pencil.

Open the app · Using it in a school?