STEM
QubitForge
A qubit is just two numbers. A gate rotates them. Measurement squares them. That is the whole of quantum — no mysticism, exact arithmetic. Start in |0⟩, apply a gate, and predict the odds: 100%? a 50/50 coin? Watch two Hadamards cancel back to certainty (interference), then entangle two qubits into a Bell pair that always agree. QubitForge enumerates the exact amplitudes on your device. Ages 15–18.
▶ Play it nowBuilt for sittings of about 25 minutes on the screen. That is our design budget, not a measurement.
#6d4bd6 Characters who teach
Meet the cast
QubitForge is for ages 15–18 — no illustrated cast; the 'characters' are the four gates whose behaviour IS the quantum idea. X (NOT) swaps the two amplitudes — purely classical. H (Hadamard) spreads amplitude evenly into a 50/50 superposition, and applied twice it interferes back to certainty. Z (phase) flips the sign of the |1⟩ amplitude — invisible to a single measurement, yet it changes what later gates do. CNOT flips a second qubit only when the first is 1; combined with H it entangles two qubits into a Bell pair that always agree. Every amplitude is computed exactly on-device (real state-vector arithmetic), so nothing here is hand-waved.
X (NOT gate)
Swaps the two amplitudes — |0⟩ becomes |1⟩; the purely classical bit-flip
H (Hadamard gate)
Spreads amplitude evenly into a 50/50 superposition; applied twice the two paths interfere and cancel back to |0⟩ — the heart of quantum computing
Z (phase gate)
Flips the sign of the |1⟩ amplitude — a phase a single measurement cannot see, but which changes what later gates do
CNOT (controlled-NOT)
Flips a second qubit only when the first is 1; with H it entangles two qubits into a Bell pair — measure one and you instantly know the other
Measurement
Squares the amplitudes — a qubit with amplitudes (a, b) reads 0 with probability a² and 1 with probability b², and measuring it collapses the state
What's inside
Learning goal
A qubit is just two numbers. A gate rotates them. Measurement squares them. That is the whole of quantum — no mysticism, exact arithmetic. Start in |0⟩, apply a gate, and predict the odds: 100%? a 50/50 coin? Watch two Hadamards cancel back to certainty (interference), then entangle two qubits into a Bell pair that always agree. QubitForge enumerates the exact amplitudes on your device. Ages 15–18.
How QubitForge handles your kid's data
- ✅ All progress, settings, and AI-generated content stays on the device
- ✅ No analytics, no tracking, no third-party SDKs
- ✅ Free — no ads, no in-app purchases
- ✅ No personal information collected from children — in line with COPPA (updated by the 2026 FTC amendments)
- ✅ No chat with strangers — play-together rooms use a short code and preset emotes, never typed messages