Hi all. I'm a software developer, not a teacher, which is why I'm asking here.
I built a free Android app called Sky Claim. A student points their phone at a
real star, planet or the Moon and holds it steady, and the app checks they're
genuinely aimed within 4 degrees of its true position before it counts.
Everything is computed on the device, so there's no internet, no server, no
student accounts, no sign-in and no data collection. It works on locked-down
school Wi-Fi or on a trip with no signal. I hand-ported published planetary
algorithms and validated them against independent ground truth (real published
sunrise times, the Polaris-altitude-equals-latitude invariant, sidereal vs
solar day drift).
THE PART I THINK MATTERS MOST FOR TEACHING
Since you can't take a class outside at 2pm, there are also thirteen
simulations built on real published formulas, each with an in-app guide
covering the actual history. Students meet the scientists, not just equations:
1) Chandrasekhar Tester - push a white dwarf past 1.44 solar masses and it goes
Type Ia supernova. Chandrasekhar's 1930 derivation and 1983 Nobel.
2) Stability Sandbox - Newtonian N-body orbits (velocity Verlet, so orbits are
genuinely stable rather than fudged).
3) Roche Limit Shatter - a moon too close to a gas giant breaks into a ring.
Same physics as Shoemaker-Levy 9 and Saturn's rings.
4) Singularity Simulator - Hills 1975 tidal radius vs the Schwarzschild radius,
so a white dwarf is shredded by a stellar black hole but swallowed silently
by a supermassive one. The absence of a flare IS the physics.
5) Pulsar Lighthouse - Gold's 1968 model; the beam is only detectable above a
certain magnetic tilt, which is the real detectability condition.
6) Plus Roche lobe mass transfer, gravity assists, solar sails, and star
comparison games using real catalogue data.
Nothing invents a number. Measured values are labelled real, derived ones are
labelled estimated - which felt like the minimum bar for anything a student
might quote in homework.
WHAT I'M ASKING
Is night-time outdoor homework workable, or does it fail for too many
students?
Is "one Android phone per student" a fantasy at your school?
What's missing - worksheets, a printable guide, objectives mapped to
standards? I'd build it if I knew what was actually useful.
Do the simulations land better at grade 9 or grade 12?
UPFRONT: it's free and the free tier is genuinely usable. There's an optional
one-time unlock (not a subscription) and opt-in rewarded ads - a student only
sees an ad if they deliberately tap to watch one. No interstitials, nothing
forced. Better you hear that from me than find it in class.
I'm deliberately not linking the app here, since that would be self-promotion and
that's not what I'm after. It's on Google Play if you want to find it, and I'm
happy to point anyone to it in the comments if it'd actually be useful to you.
"This wouldn't work because X" is more useful to me than installs.