Comparison

PP+ Image Formation vs Astable

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

Head to head
About

PP+ Image Formation

Features
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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+ Newtonโ€™s 2nd Law lab. For those whoโ€™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.

About

Astable

This application provides a powerful structural mechanics solver with a graphic editor, code editor, and workspace. It allows for detailed mechanics parameter settings and offers a rich theme color scheme, making it ideal for large screen devices.

Highlights
  • Graphic editor
  • Code editor
  • Workspace
  • Mechanics parameter settings
  • Rich theme color scheme
  • Large screen device optimized
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Astable Grand is a beautiful and powerful structural mechanics solver with graphic editor, code editor, workspace, mechanics parameter settings, rich theme color scheme, etc. It is suitable for large screen devices such as tablet and PC.

Screenshots

Astable4 screens

Verdict

The call

The clearest difference is update cadence: Astable at every 2 weeks against PP+ Image Formation's every 3 months. Astable also leads on device support (4 vs 1) and iOS requirement (12.0 vs 18.0). PP+ Image Formation's advantage is price ($1.99 vs $4.99). On ads and in-app purchases there is nothing between them.

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

CostPrice ยท In-app purchases ยท Ads ยท Monetization

PP+ Image Formation costs $1.99 and Astable $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

PP+ Image Formation ships an update every 3 months, Astable every 2 weeks. The most recent releases landed on February 1, 2026 and July 8, 2026 respectively.

Scorecard4 real differences ยท 4 level
PP+ Image Formation versus Astable: the parameters behind the verdict, then further details
ParameterPP+ Image FormationAstable
Price$1.99 โ€” better$4.99
Positive reviewsโ€”50.0% of reviews
Update frequencyEvery 3 monthsEvery 2 weeks โ€” better
AdsNoNo
In-app purchasesNoNo
Monetizationโ€”Paid
DevicesiPadiPhone, iPad, iPod, Mac โ€” better
Requires iOS18.012.0 โ€” better
Further details โ€” not scored
Size91 MB35 MB
Age rating4+4+
DeveloperPolyhedron Learning Media, Inc.ๅฎถ่ฑช ้ฒ

In-app purchases

None

PP+ Image Formation

No in-app purchases

None

Astable

No in-app purchases

Questions

Is PP+ Image Formation free?
PP+ Image Formation costs $1.99, with no in-app purchases.
Is Astable free?
Astable costs $4.99, with no in-app purchases.
Do PP+ Image Formation or Astable have ads?
Neither PP+ Image Formation nor Astable shows ads.
Which is updated more often, PP+ Image Formation or Astable?
PP+ Image Formation ships an update every 3 months, and Astable every 2 weeks. Most recently, PP+ Image Formation was updated on February 1, 2026 and Astable on July 8, 2026.

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