PP+ Image Formation vs StoneBusters
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PP+ Image Formation
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The Image Formation Using Lenses lab uses an optical bench to determine the focal length of a converging lens and to investigate the relationship between the object distance and the image distance. It is part of Polyhedron Physics Plus, a set of 24 iPad apps for use in the classroom. To see how they work, try the FREE PP+ Newton’s 2nd Law lab. For those who’d prefer to develop their own experiments, the PP Optical Bench & Lenses app features a similar apparatus without lab procedures and other supporting materials. In addition to a 3D simulation that produces realistic data, each lab includes introductory videos, background theory, experimental procedure, analysis and reporting tools, pre-lab quiz, post-lab questions, and teacher support materials. The experimental data produced by the simulations are realistic, including random and systematic errors. These features allow students to use standard data analysis and error analysis techniques to report on their own unique data, just as if the experiment had been performed using hands-on equipment. These labs can serve as replacements for hands-on labs, especially when equipment is not available, or as supplements to hands-on labs. They are also a suitable option for students in distance learning and home school situations. Formative and summative evaluations showed no significant difference in learning between students using the virtual labs and those using hands-on labs. Preliminary results suggest increased learning by students using the virtual labs as supplements to hands-on. Polyhedron Physics was developed by Polyhedron Learning Media, Inc. with partial funding provided under contract numbers ED-07-CO-0040 and ED-IES-11-C-0029 from the Institute of Education Sciences in the U.S. Department of Education through the Small Business Innovation Research (SBIR) program.
StoneBusters
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On the mobile screen, users can access data from the Minor Planet Center, such as the NEO Confirmation Page (NEOCP) and the Possible Comet Confirmation Page (PCCP). A list of recently observed NEOs, organized by classification: unnumbered single-opposition, multiple-opposition, and numbered objects. Object from NEOfixer (University of Arizona) may be visualized, filtered and sorted. A personalized “starred” list let the user to have a list of preferred objects available for quick view and a custom list of selected objects, based on various physical and observational parameters may also be listed. Additionally, a list of objects that were removed from the NEOCP is available, with each object graphically categorized by its final classification (e.g., NEO, comet, artificial object, missing object, etc.). Once an object is selected, the app provides detailed information, including: an observation summary (observatory codes and details), Ephemeris calculation, Orbital elements and uncertainty orbit graphic representation for NEO. Users can also "identify" an object displaying physical and orbital data retrieved from NASA JPL's Solar System Dynamics (SSD) database. This includes secondary designations, discovery circumstances, and citation text (if available). There is also the possibility to “WAMO” an object with personal MPC observatory code to obtain the status of observation, and also have Summary WAMO data visualized as bar histograms and tables. As a curiosity—and to assist users without an observatory code—if location permissions are enabled, the app can list the 30 nearest observatory codes based on distance from the user's device. (For security reasons, the exact coordinates or map positions of the observatories are not displayed, and never will be.) The app relies on APIs provided by: - The International Astronomical Union's Minor Planet Center - NASA Jet Propulsion Laboratory's SSD and CNEOS (Center for Near-Earth Object Studies) - NEOfixer (University of Arizona) Some calculations, such as topocentric ephemerides, are performed directly on the device. While the app provides convenient, on-the-fly previews of information, users are strongly encouraged to refer to the official sources mentioned above for authoritative and professionally calculated data.
Screenshots
Verdict
The clearest difference is price: StoneBusters at Free against PP+ Image Formation's $1.99. StoneBusters also leads on update cadence (every 2 weeks vs every 3 months) and device support (4 vs 1). On ads and in-app purchases 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
StoneBusters is free to download; PP+ Image Formation costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.
PP+ Image Formation ships an update every 3 months, StoneBusters every 2 weeks. The most recent releases landed on October 15, 2026 and October 4, 2026 respectively.
| Parameter | PP+ Image Formation | StoneBusters |
|---|---|---|
| Price | $1.99 | Free — better |
| Update frequency | Every 3 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Devices | iPad | iPhone, iPad, iPod, Mac — better |
| Requires iOS | 18.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 91 MB | 55 MB |
| Age rating | 4+ | 4+ |
| Developer | Polyhedron Learning Media, Inc. | FABRIZIO TOZZI |
In-app purchases
PP+ Image Formation
No in-app purchases
StoneBusters
No in-app purchases
Questions
Is PP+ Image Formation free?
Is StoneBusters free?
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Which is updated more often, PP+ Image Formation or StoneBusters?
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