# HARAKU - Wave Physics — Interactive Wave Simulator

> Interactive Wave Simulator (iPhone/iPad app by Fuji Bit Inc..)

- Source: https://appshunter.io/ios/app/haraku-wave-physics/id6759958253 (this page in markdown: same URL + `.md`)
- Developer: [Fuji Bit Inc.](https://appshunter.io/developer/1874205957)
- Category: Education, Utilities
- Price: Free
- Age rating: 4+
- Requires: iOS 15.0 · 24 MB
- Languages: American English, French (France), German (Germany), Hindi, Indonesian, Italian, Japanese, Korean, Brazilian Portuguese, Russian and 6 more
- Released: 2026-03-24
- Data updated: 2026-10-22

## What is HARAKU?

HARAKU is an interactive educational app that visualizes the physics of waves in real time. Designed for students, teachers and anyone curious about science, it lets you control how waves behave just by moving sliders, so you can intuitively connect the equations with what you see.

Developer: Fuji Bit Inc.

HARAKU is the waves edition of the "-raku" physics simulation series. It helps you understand the wave concepts taught in middle school, high school and university physics as moving pictures, not just formulas.

12 simulations in 3 categories:

- Wave basics
- Superposition: Combine two sine waves and watch them reinforce or cancel. Change the amplitude, frequency and phase of each wave independently to see the principle of superposition.
- Reflection: See the moment a traveling wave reflects at a boundary. Switch between a fixed end (phase inverts) and a free end (phase is kept), with the incident, reflected and total waves shown in three layers.
- Standing waves: Watch standing waves on a string fixed at both ends while changing the harmonic. Check the positions of nodes and antinodes and the effect of tension and damping.
- Fourier synthesis: See how square, triangle and sawtooth waves are made of sine waves (harmonics). The more terms you add, the closer the sum gets to the target waveform.

- Sound waves
- Beats: Overlap two waves with slightly different frequencies and feel the beats. The envelope clearly shows how the amplitude changes.
- Doppler effect: Drag the source and see the wavefronts bunch up in front and spread out behind. Go past Mach 1 to create a shock wave.
- Air column resonance (new): Switch between closed and open pipes and change the length, air temperature and resonance number to see the resonant frequency and wavelength. The motion of air particles (a longitudinal wave) is shown next to a graph that draws the displacement as a transverse wave, so you can find the nodes and antinodes.

- Waves in a plane & light
- 2D ripples: Tap the screen to place sources; a numerical solution of the wave equation draws the interference pattern in real time.
- Interference: See the lines of reinforcement and cancellation made by two point sources. The fringe spacing changes with the source separation, frequency and speed.
- Diffraction: See waves spread through a slit according to Huygens' principle. The ratio of slit width to wavelength changes how strongly they diffract.
- Refraction: Visualize Snell's law, including how waves bend at a boundary and total internal reflection at large angles.
- Thin-film interference (new): See why soap films and oil slicks shine in color by changing the film thickness, refractive index, angle and what lies below (air or glass). The phase shift on reflection, the color seen under white light, a color-vs-thickness strip and a reflectance-vs-wavelength graph are shown together.

Features:
- Clean, easy-to-read design (dark and light themes)
- Home screen organized by category
- Intuitive parameter sliders: touch, try and understand
- An explanation sheet with formulas for every simulation
- On iPad in landscape, the canvas 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

## Is HARAKU safe?

Not enough ratings yet to assess HARAKU.

## Is HARAKU legit?

HARAKU - Wave Physics appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for HARAKU is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 5 releases)

### 6.0.1 — 2026-10-19

- Redesigned screens (home organized by category, tips and a play button in the control panel)
- New modes: air column resonance and thin-film interference (12 modes in total)
- Now in 16 languages (added Chinese Simplified/Traditional, Korean, Spanish, Portuguese, German, French, Hindi, Indonesian, Russian, Italian, Turkish, Thai and Vietnamese)
- On iPad in landscape, the canvas and control panel are shown side by side
- Ads are now provided by Pangle; "Ad settings" added to "About"
- Requires iOS 15.0 or later

### 5.0 — 2026-05-10

- New "Fourier Synthesis" simulation - build square, triangle, and sawtooth waves from harmonics in real time
- New "Reflection" simulation - toggle between fixed and free boundaries and watch standing waves form from incident and reflected waves
- Corrected the sawtooth harmonic coefficients to match the target waveform

### 4.0 — 2026-04-30

- New "Interference" simulation — visualize two-point-source interference fringes in real time
- New "Diffraction" simulation — a plane wave through a slit, spreading via Huygens' principle
- Developer attribution unified to Fuji Bit Inc.

### 3.0 — 2026-03-29

We've made the app free

### 2.0 — 2026-03-24

• Added English localization — the app now supports both Japanese and English
• Localized app name and system dialogs for English users
• Minor formula display improvements

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## More apps by Fuji Bit Inc.

- [SUUGAKU](https://appshunter.io/ios/app/suugaku/id6759102221)
- [BUTURAKU](https://appshunter.io/ios/app/buturaku/id6759213255)
- [PAKEDOU](https://appshunter.io/ios/app/pakedou/id6759820254)
- [OKURERUNA！](https://appshunter.io/ios/app/okureruna/id6759956971)
- [KORAKU](https://appshunter.io/ios/app/koraku/id6760215571)

All apps by Fuji Bit Inc.: https://appshunter.io/developer/1874205957

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-22.*