Comparison

PP+ Simple Harmonic Motion vs Stochastic Signal Processing

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

Head to head
About

PP+ Simple Harmonic Motion

Explore the principles of simple harmonic motion with a virtual spring-mass system. This educational tool provides realistic 3D simulations, data analysis tools, and comprehensive learning materials for students.

Highlights
  • 3D spring-mass simulation
  • Realistic data with errors
  • Data analysis and reporting tools
  • Introductory videos and background theory
  • Pre-lab quiz and post-lab questions
  • Teacher support materials
Features
Read full description

The Simple Harmonic Motion lab uses a spring-mass system to investigate relationships between the spring constant, mass, amplitude of oscillation, and period of oscillation for a mass on a spring. 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 Spring Mass System 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

Stochastic Signal Processing

Explore the processing of random signals like speech, music, and climate data. This interactive textbook offers dynamic information, films, animations, and 59 real-time laboratory experiments using your device's camera and microphone. It's designed for those with prior signal processing and probability theory knowledge.

Highlights
  • Interactive textbook format
  • Dynamic information display
  • Films and animations
  • 59 laboratory experiments
  • Real-time signal processing
  • Homework problems
Features
Read full description

Speech, music, seismic vibrations, oil prices, and climate measurements are all examples of stochastic (random) signals. In this textbook—intended for individuals with prior training in introductory signal processing and introductory probability theory—we develop techniques to process such signals to extract useful information. We present case studies ranging from music to photographic images to oil prices to climate data to the motion of individual biomolecules. This textbook, as an interactive textbook ("iBook"), makes use of your device's ability to display dynamic information through films and animations and to hear the results of the techniques applied to music. At the end of every chapter there are homework problems ranging from easy to "olympic". We make use of your device's interactive capabilities to offer 59 laboratory experiments in signal processing. The experiments use the camera, the microphone, the speakers, and the graphical user interface. These experiments are not simulations; they are examples of real digital processing of signals in your device. In this time of at-home and online learning, this is the way to learn signal processing through study and experimentation.

Screenshots

Stochastic Signal Processing4 screens

Verdict

The call

The clearest difference is review sentiment: Stochastic Signal Processing at 67% against PP+ Simple Harmonic Motion's 0%. Stochastic Signal Processing also leads on price (Free vs $1.99) and update cadence (every 5 weeks vs every 29 months). 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

CostPrice · In-app purchases · Ads · Monetization

Stochastic Signal Processing is free to download; PP+ Simple Harmonic Motion costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

PP+ Simple Harmonic Motion ships an update every 29 months, Stochastic Signal Processing every 5 weeks. The most recent releases landed on June 8, 2026 and September 25, 2026 respectively.

Scorecard6 real differences · 4 level
PP+ Simple Harmonic Motion versus Stochastic Signal Processing: the parameters behind the verdict, then further details
ParameterPP+ Simple Harmonic MotionStochastic Signal Processing
Price$1.99Free — better
Rating—4.7 (6 ratings) — better
Positive reviews0.0% of reviews66.7% of reviews — better
Number of ratings—6 — better
Update frequencyEvery 29 monthsEvery 5 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPadiPhone, iPad, iPod — better
Requires iOS18.015.0 — better
Further details — not scored
Size115 MB73 MB
Age rating4+4+
DeveloperPolyhedron Learning Media, Inc.Ian Young

Customer experience

PP+ Simple Harmonic Motion

Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

Stochastic Signal Processing

All ratings6 ratings
Positive83.3%
Neutral16.7%
Negative0.0%
Written reviews3 reviews
Positive66.7%
Neutral33.3%
Negative0.0%

In-app purchases

None

PP+ Simple Harmonic Motion

No in-app purchases

None

Stochastic Signal Processing

No in-app purchases

Questions

Is PP+ Simple Harmonic Motion free?
PP+ Simple Harmonic Motion costs $1.99, with no in-app purchases.
Is Stochastic Signal Processing free?
Stochastic Signal Processing is free to download, with no in-app purchases.
Do PP+ Simple Harmonic Motion or Stochastic Signal Processing have ads?
Neither PP+ Simple Harmonic Motion nor Stochastic Signal Processing shows ads.
Which is updated more often, PP+ Simple Harmonic Motion or Stochastic Signal Processing?
PP+ Simple Harmonic Motion ships an update every 29 months, and Stochastic Signal Processing every 5 weeks. Most recently, PP+ Simple Harmonic Motion was updated on June 8, 2026 and Stochastic Signal Processing on September 25, 2026.

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