KORAKU vs Motion Physics Gallery

KORAKU is an interactive educational app that visualizes how light behaves in real time. Bend rays with lenses and mirrors, overlap light as a wave, and explore color and photons to connect the equations with what you see. Developer: Fuji Bit Inc. KORAKU is the optics edition of the "-raku" physics simulation series. It turns the optics of school and university physics into moving pictures, not just formulas. 12 simulations in 3 categories: - Rays & Images - Lens: Trace rays through convex and concave lenses. Change the focal length, object distance and height to see the image switch between real and virtual, inverted and upright. Explore 1/f = 1/a + 1/b. - Mirror: Switch between concave and convex mirrors. Move the radius R and object distance a to see how the image changes around the focal point F and center of curvature C, and why a virtual image appears behind the mirror. - Eye & Glasses (new): See the cornea and lens focus an image on the retina. Choose a normal, nearsighted or farsighted eye and change the viewing distance, glasses power (diopters) and accommodation to see where the image forms and how blurry it looks. One tap sets matching glasses. - Prism: Watch white light split into a spectrum. Change the apex angle, angle of incidence and refractive index to see dispersion bend each color differently, with the deviation and minimum deviation. - Optical fiber: See light travel by total internal reflection. Change the launch angle and refractive indices to explore the critical angle, numerical aperture (NA) and when light leaks into the cladding. - Light as a Wave - Diffraction grating: Change the number of slits, spacing and wavelength to find the bright lines at d sin(theta) = m lambda, and watch them sharpen as slits are added. - Thin film: Recreate the colors of soap bubbles and oil films. Change the thickness, refractive index and angle to shift the bright and dark wavelengths. - Polarization: Rotate a polarizer and an analyzer to see Malus's law, I = I0 cos^2(theta): brightest at 0 and 180 degrees, blocked at 90. - Color & the Nature of Light - Color mixing: Compare additive mixing of light (RGB) with subtractive mixing of paint (CMY) using three sliders. - Rainbow: Follow sunlight as it refracts into a raindrop, reflects inside and refracts out. See why the primary bow appears about 42 degrees from the antisolar point, the secondary about 51 degrees, with the colors reversed. - Blue Sky & Sunset (new): See sunlight scattered in the atmosphere. Switch between Rayleigh scattering (proportional to 1/lambda^4) and Mie scattering (cloud droplets, haze), and change the sun altitude and air density. As the air mass grows, the sky and sun turn from daytime blue to sunset colors. - Photoelectric effect: Shine light on a metal and watch electrons fly out. Change the frequency, intensity and work function to explore E = hf, Kmax = hf - W and the threshold frequency f0, with the visible and UV bands marked. Features: - Clean, modern design (dark and light themes) - Home screen organized by category - Tips and a play button in the control panel - Parameter sliders with results that update in real time - Legends and labels for every symbol and colored ray on screen - An explanation sheet with formulas for every simulation - In landscape, the canvas and control panel are shown side by side - Supports larger text sizes - VoiceOver reads out each screen's result (real or virtual image, total internal reflection, and more) - 73 languages including English and Japanese, 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 The "-raku" educational app series: - SUUGAKU - Mathematics - BUTURAKU - Mechanics - DENRAKU - Electromagnetism - HARAKU - Waves - KORAKU - Optics

Motion Physics Gallery is a collection of interactive physics simulations. The app interface and learning explanations are in Japanese. Change height, gravity, mass, speed, angle, wavelength, focal length or voltage, then tap GO. Run A and B together to observe how changing one condition affects the result while keeping the other conditions shared. 11 INTERACTIVE EXHIBITS - Motion under gravity: falling, upward throws, horizontal and angled launches, and air resistance. - Pendulum: length, gravity, amplitude and period. - Collisions: mass, velocity and motion before and after a collision. - Levers: the fulcrum, lever arms and balance of forces. - Buoyancy: object and liquid density, floating and sinking. - Wave superposition: two waves and their combined wave. - Standing waves: string length, frequency, nodes and antinodes. - Doppler effect: a moving sound source and changes in observed pitch. - Reflection and refraction: angle of incidence, refractive index and total internal reflection. - Lenses: converging and diverging lenses, focus, images and two-lens setups. - Electric circuits: voltage, resistance, current and bulb brightness. CHANGE, RUN AND COMPARE - Compare A and B with one selected condition changed. - Start synchronized animations with GO. - Adjust sliders. Selected experiments also let you drag objects or controls directly in the experiment area. - Observe motion using time-spaced images, vectors and scales. - In Motion under Gravity, switch between 2D and a 3D view that you can rotate and zoom. - In Doppler Effect, compare the source tone with the observed tone. - Animated tutorials demonstrate how to use the experiments. Each exhibit uses a simplified educational model, with its assumptions explained in the app. The models do not reproduce every real-world effect of friction, shape or the environment. The experiments run on your device and can be used offline. No account registration or ads. LANGUAGE The app interface and learning explanations are in Japanese. This store listing is provided in English.