SEIRAKU vs 元素カード119

SEIRAKU is an interactive educational app for exploring celestial mechanics through beautiful, real-time simulations. Part of the popular science learning series including SUUGAKU (math), BUTURAKU (physics), DENRAKU (electricity), HARAKU (waves), and NETURAKU (thermodynamics). This installment focuses on celestial mechanics — ten simulations that let you experience the elegant laws governing our universe. 【10 Simulations】 ▶ Orbital Motion Simulate planets orbiting a central body under gravity. Freely adjust mass, speed, and the number of planets. Stable Verlet (leapfrog) integration produces beautiful orbital trails in real time. ▶ Universal Gravitation Visualize the gravitational field of multiple massive bodies using vector arrows. Tap anywhere to add test particles and watch how they move through the field. Experience Newton's law of gravitation. ▶ Three-Body Problem When three stars pull on one another, the motion turns wildly complex — most starting conditions diverge completely, while a few special ones trace beautiful periodic orbits. Choose between Stable Triangle, Figure-8 Orbit, Collinear, and Unstable presets to feel how gravity and velocity intertwine. ▶ Tidal Force Visualize the tidal deformation that the Moon's gravity exerts on Earth. Observe how tidal force vectors and ocean bulges (3cos²θ − 1) change in real time as the Moon orbits. Adjust distance and mass to explore the concept of the Roche limit. ▶ Kepler's Laws Experience Johannes Kepler's three laws of planetary motion in a single screen. Adjust eccentricity and semi-major axis freely, and see the equal-area law (2nd law) visualized through swept sectors. Compare the speed difference between perihelion and aphelion. ▶ Gravity Slingshot A spacecraft uses a planet's gravity to change speed and direction — the technique used by Voyager and Hayabusa. Adjust planet mass, launch speed, and approach offset to see how the trajectory, speed gain, and deflection angle change. ▶ Hohmann Transfer Visualize the classical minimum-fuel two-burn transfer between two circular orbits. The first burn (Δv₁) places the craft on a half-elliptical transfer; the second (Δv₂) circularizes onto the outer orbit. Watch Δv, the transfer half-period, and eccentricity update live — the same maneuver used in real interplanetary missions. ▶ Exoplanet Transit Simulate the dimming when a planet passes in front of its host star, along with the resulting light curve. Tune the planet/star radius ratio and impact parameter to see how transit depth and shape change, with limb-darkening producing the characteristic U-shaped curve — the technique used by NASA's Kepler and TESS missions. ▶ Gravitational Lens Visualize how light passing near a massive object (a galaxy or black hole) is bent by the curvature of spacetime. Change the lens mass and source position to watch parallel rays focus and form the Einstein ring when the source lines up directly behind it. Deflection uses the general-relativistic value (twice the Newtonian result). ▶ Axial Precession Visualize, in pseudo-3D, how the spin axis of a rapidly rotating body slowly sweeps out a cone under gravitational torque. Adjust tilt, spin rate, and torque to observe the cone, the changing pole star, and the precession period — the same phenomenon that makes Earth's axis complete one circuit in about 25,800 years. 【Features】 • Real-time parameter adjustment in all simulations • Physics formulas and live numerical readouts • Dark mode / Light mode support • Intuitive, beautiful UI • Japanese / English supported • Minimal ads — banner only at the bottom 【Pricing & Purchases】 • This app is free to use. • There are no in-app purchases. • It is supported by advertising (Google AdMob banner ads). 【Who is this for?】 • Students studying celestial mechanics in physics class • Anyone who wants to intuitively understand the laws of the universe • Teachers looking for interactive teaching materials • Everyone curious about astronomy and space

「元素カード119」は、元素周期表の全119元素をカード形式で学べる学習アプリです。 【元素カード】 各元素をカードで表示。元素記号、原子番号、原子量、電子配置などの基本情報を一覧できます。カードをめくるように楽しく学習できます。 【周期表ビュー】 インタラクティブな周期表から各元素の詳細情報にアクセス。元素の位置関係や族・周期の特徴を視覚的に理解できます。 【グループ別学習】 アルカリ金属、ハロゲン、希ガスなど、元素グループごとにまとめて学習。共通の特性を効率的に把握できます。 【暗記テスト】 元素記号や原子番号の暗記テストで理解度をチェック。繰り返し学習で確実に覚えられます。 中学・高校の理科学習から、大学受験の化学対策、化学に興味をお持ちの方まで、幅広くお使いいただけます。