Comparison

CHIRAKU vs PROjections

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

CHIRAKU

Features
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CHIRAKU is an interactive educational app that brings earth science to life with moving diagrams. Plate motion, earthquakes, volcanoes, rocks, the Earth's interior, geomagnetism and atmospheric circulation are each shown in four phases, step by step, ending with a real landform or a typical observation. Every element in the diagram has a name label, so you can always see what is happening. Developer: Fuji Bit Inc. CHIRAKU is the earth-science edition of the "-raku" science simulation series. It helps you understand what you learn in middle-school and high-school earth science and introductory university geoscience, as if the textbook figures had started to move. 9 simulations in 3 categories: Moving Plates & Earthquakes: - Plate tectonics: See landforms form at the three kinds of plate boundaries (divergent, convergent and transform) in four stages, ending with the Mid-Atlantic Ridge, the Japan Trench and the Japanese islands, and the San Andreas Fault. - Seismic waves: Watch P waves (longitudinal) and S waves (transverse) spread from the focus and reach three stations, where seismographs record the initial tremor and the main shaking. The farther the station, the longer the S-P time. - Epicenter location: Use Omori's formula to turn the S-P times at three stations into distances, and find the epicenter where three circles meet. Volcanoes & Rocks: - Volcanic eruption: See how the eruption style changes from Hawaiian to Strombolian, Vulcanian and Plinian as the magma's viscosity and gas content increase. - Lava flow: Release four lavas of different viscosity one after another and compare their speed, thickness and how far they travel. The speed is calculated with Jeffreys' equation. - Rock cycle (new): Follow one rock as it travels granite → mud → mudstone → gneiss → magma, changing between igneous, sedimentary and metamorphic rock. The current depth and temperature are shown too. Inside and Around the Earth: - Earth interior: Trace the paths of P and S waves through the crust, mantle, outer core and inner core, and see from the S-wave shadow zone that the outer core is liquid. - Geomagnetism: Explore the Earth's field lines, the magnetosphere, how it shields us from the solar wind, and the geomagnetic reversal about 770,000 years ago (the origin of the name Chibanian). - Atmospheric circulation (new): Starting from heating at the equator, see the three cells (Hadley, Ferrel and polar) and the belts of trade winds, westerlies and polar easterlies form, and why rainy belts and desert belts appear. Features: - Every simulation runs in 4 phases, with the phase name and a one-line explanation always shown at the top - A name label on every element; the last phase shows the real example and stops automatically - Move between phases with the previous and next buttons and set the speed from 0.5x to 3x - An explanation sheet with formulas for every simulation (Omori's formula, Snell's law, the Coriolis force and more) - Clean, easy-to-read design (dark and light themes) - On iPad in landscape, the diagram and control panel are shown side by side - 16 languages (Japanese, English, Chinese Simplified/Traditional, Korean, Spanish, Portuguese (Brazil), German, French, Hindi, Indonesian, Russian, Italian, Turkish, Thai, Vietnamese), following your device language - No sign-in: start exploring right away Price: - Free - In-app purchases: none - Subscriptions: none - Ads: a banner ad by Pangle at the bottom of the screen

About

PROjections

Features
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Entraînez-vous à la projection de vecteurs dans une base à l'aide d'une infinité d'exemples générés aléatoirement. Un mode 'Aide' est prévu, vous permettant de modifier dynamiquement la valeur des angles sur la figure. Défiez vos amis sur une session de 10 projections identiques pour vous deux.

Screenshots

CHIRAKU4 screens
PROjections4 screens

Verdict

The call

The clearest difference is ads: PROjections at none against CHIRAKU's shown. PROjections also leads on update cadence (daily vs every 5 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

CHIRAKU ships an update every 5 months, PROjections daily. Both last shipped on October 31, 2026.

Scorecard2 real differences · 4 level
CHIRAKU versus PROjections: the parameters behind the verdict, then further details
ParameterCHIRAKUPROjections
PriceFreeFree
Update frequencyEvery 5 monthsDaily — better
AdsYesNo — better
In-app purchasesNoNo
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.015.0
Further details — not scored
Size25 MB72 MB
Age rating4+4+
DeveloperFuji Bit Inc.Thomas Roy

In-app purchases

None

CHIRAKU

No in-app purchases

None

PROjections

No in-app purchases

Questions

Is CHIRAKU free?
CHIRAKU is free to download, with no in-app purchases.
Is PROjections free?
PROjections is free to download, with no in-app purchases.
Do CHIRAKU or PROjections have ads?
CHIRAKU shows ads; PROjections does not.
Which is updated more often, CHIRAKU or PROjections?
CHIRAKU ships an update every 5 months, and PROjections daily. Most recently, CHIRAKU was updated on October 31, 2026 and PROjections on October 31, 2026.

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