Light Lab vs KORAKU

Move light. Refract it. Reflect it. Light Lab is an interactive science app where you learn by playing with light. 【Discover the Magic of Light】 Touch the screen and move the light source. Rotate lenses and change refractive indices. Watch light rays change in real-time! Create rainbows, bounce light off mirrors. "Why does this happen?" As you play, you'll naturally understand how light works. 【Perfect For】 ・Students learning about light in elementary or middle school ・Anyone studying light propagation, reflection, and refraction ・Teachers who want to make science class more engaging ・Anyone curious about optics 【What You Can Do】 ◆ Real-Time Light Manipulation Move light sources and lenses to see light rays change instantly. Rotation, translation, refractive index changes—all operations reflect in real-time. ◆ Place Various Lenses Triangular prisms, convex lenses, concave lenses, diamonds, spheres, mirrors, and more. Place up to 10 lenses simultaneously to recreate complex light behaviors. ※2 lens types are free (triangle prism, biconvex lens) ◆ 3 Types of Light Sources ・Parallel: Like sunlight ・Spotlight: Like a light bulb ・Dispersion: Rainbow-colored light ◆ Create Animations Save lens and light arrangements as "scenes." Connect multiple scenes to create animations showing how light transforms. ◆ Save and Share Save your creations in the app. Generate QR codes to share with friends and classmates. 【For Teachers】 Designed as an educational tool for classroom use. ・Visually understand light propagation, reflection, and refraction ・Simulate phenomena that are difficult to explain, like total internal reflection and dispersion ・Students can experiment independently—perfect for inquiry-based learning ・Save and share scenes as teaching materials Try it for free first! 【Features in Detail】 ＜Light Source Adjustments＞ ・Position and rotation ・Adjust number of rays and width ＜Lens Adjustments＞ ・Position and rotation ・Refractive index settings ・Size adjustment ・Curvature adjustment for convex and concave lenses ＜Scene Features＞ ・Create up to 5 scenes ・Smooth animations between scenes ＜File Features＞ ・Local saving ・QR code sharing 【Pricing】 Basic features are free. ◆ Lens Unlock (One-time purchase) One-time purchase. Unlock premium lenses (plano-convex lens, biconcave lens, diamond, sphere, mirror, reflector). ◆ Lens Ticket Issuing Feature (One-time purchase) ※Requires "Lens Unlock" purchase first Generate QR codes to unlock all lenses on other devices for 1 year. Tickets can be issued repeatedly—perfect for teachers adopting the app school-wide or classroom-wide. 【Privacy】 ・No personal information is collected ・Works offline by default ・Internet connection required only for accurate time retrieval when using Lens Ticket feature 【Requirements】 ・iPhone / iPad ・iOS 16.0 or later 【Support】 Detailed instructions are available in the in-app "How to Use" menu. For questions, contact us via the support page. Bring the world of light closer. Let's play with light!

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