Academics
WobbleForge
The phone as a measuring instrument, and every number from the world comes with a wobble. Time a pendulum three times and see the spread: does a heavier weight change the swing? Does a longer string? Then measure a tree's height with paces and tilt. Predict, measure three times, read the spread, say what you found.
▶ Play it nowBuilt for sittings of about 20 minutes on the screen. That is our design budget, not a measurement.
Meet your mentor
Every Spark & Anvil app has a friendly mentor character that demonstrates, asks, and patiently scaffolds learning.
Mentored by Wobbly
#1f6b5c Characters who teach
Meet the cast
WobbleForge's measurers know a number from the world is never exact. Wobbly measures everything three times, Swingle times the pendulum, Tiltwhit sights the treetop, and Spreadle says how far apart the readings are.
Wobbly
measures three times, because one reading could be a fluke
Swingle
A gibbon who swings - times ten swings, not one, so a slow thumb matters less
Tiltwhit
A giraffe who sights the treetop - distance and tilt together give the height
Spreadle
An owl who compares - a difference smaller than the spread is not a real difference
What's inside
Learning goal
The phone as a measuring instrument, and every number from the world comes with a wobble. Time a pendulum three times and see the spread: does a heavier weight change the swing? Does a longer string? Then measure a tree's height with paces and tilt. Predict, measure three times, read the spread, say what you found.
Mentored by Wobbly — no data leaves the device.
How WobbleForge 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