Pocket Experiments Science Lab

Twenty-six rooms. Not a workbook — a bench in each one. You set the parts out yourself, turn the knobs, and measure with the instruments.

• Hang as many weights as you like anywhere along a balance beam, and even it up
• Drag molecules onto the bench and see what they form
• Set a magma's silica and the depth where it freezes, erupt it, then look at the rock through a hand lens and measure the grains
• Stretch two strings, detune one, and listen to the beats
• Drop three seismometers on a map; three circles meet at one point, and that point is the epicenter

Every number is measured off the picture. Nothing here works a value out of a formula and then "checks" it against the same formula. The grains under the lens are really drawn, and their size is really measured. Turn a knob and the picture changes; when the picture changes, the numbers change with it.

Every room has three steps:
1. Move it — turn one knob and watch what changes
2. Count it — line the measurement up against the formula and look at the gap
3. Check it — one question, and the reason either way

Every room also has a question box. Clear it and the room moves up a tier: none → bronze → silver → gold. There are 78 questions in all. But the questions are not the main act. Playing with the bench is; a question is the detour you take when you think “wait — could I actually build that?”

The topics are middle school and high school science: forces and motion, springs and buoyancy, pendulums, circuits, electromagnets, ray optics, lenses, sound, changes of state, solubility, titration, electrolysis, chemical reactions, preparing and collecting gases, the microscope, cell division, photosynthesis, flower structure, heredity, strata, rocks and volcanoes, earthquakes, and the sky. Three neighbors of science come along too: probability, logic gates and regular expressions.

ADS AND THE ONE-TIME PURCHASE
The app is free and shows ads: a banner along the bottom of the screen, and a full-screen ad when you open the app. All 26 rooms and all 78 questions are open from the first launch. There is exactly one in-app purchase and all it does is turn the ads off — it unlocks nothing and adds nothing. It is a single one-time purchase with no subscription (¥5,000 in Japan; the price for your country is shown in the app).

Not based on, or affiliated with, any particular textbook.