An eight-project Arduino simulator! Every project includes real Arduino code, a live circuit diagram, and a Serial Monitor at the bottom. 💡 LED Blink — The "Hello World" of hardware. A 220Ω resistor and LED circuit, digitalWrite(13, HIGH/LOW) code, and a PWM timing diagram all run simultaneously. 🔘 Button & LED — A live visualisation of INPUT_PULLUP. Click the button to light the LED, and see the inverted logic (LOW = pressed) explained in context. 🌓 PWM Fade — Controls LED brightness with analogWrite(9, 0–255). The PWM waveform and duty cycle update in real time as the LED breathes. 🌡️ Analog Sensor — Turn the potentiometer dial to read ADC values from 0 to 1023, then watch map() rescale them to the PWM range (0–255). Includes a voltage divider explanation. ⚙️ Servo Motor — Control the servo with an angle slider. The relationship between PWM pulse width (0.5ms – 2.5ms) and output angle is visualised live. 🎨 RGB LED — Mix any colour with the R, G, and B sliders. Press AUTO for an automatic rainbow cycle. A colour wheel is shown alongside. 📡 Ultrasonic Sensor — Shows how the HC-SR04 works with a TRIG/ECHO timing diagram. Verify the formula cm = round-trip time (µs) / 58 directly. 🚦 Traffic Light — Demonstrates a Finite State Machine (FSM). The RED → RED+YELLOW → GREEN → YELLOW cycle runs alongside a live state-transition diagram.

🪐 Orrery Real-time orbital simulation using logarithmic distance scaling. Click any planet to reveal its age, formation date on the Cosmic Calendar, orbital period, surface temperature, gravity, and an age-bar showing what percentage of the Universe's lifetime it has existed. Sliders control simulation speed, orbit ring opacity, and planet display scale. Saturn's rings and the Moon's orbit are rendered separately. ⏳ Cosmic Clock Carl Sagan's Cosmic Calendar — 13.8 billion years compressed into a single year. A circular clock face marks key events from the Big Bang to the present: galaxy formation, the Sun igniting, Earth's birth, the Cambrian Explosion, dinosaurs, and the appearance of humans. The current real-world time updates live at the centre every second. 📅 Timeline 22 major cosmic events from the Big Bang to the present, laid out on a horizontal timeline. Labels alternate above and below the axis for readability. A scrollable side panel provides a detailed description of each event alongside its age in billions of years. ⚖️ Age Compare Horizontal bar chart comparing the ages of the Universe, the Milky Way, the Sun, all eight planets, and the Moon. Each bar shows how many billion years after the Big Bang the object formed, its age as a percentage of the Universe's total age, and its equivalent position on the Cosmic Calendar in months. 🌡 Properties Five switchable data modes — Size, Temperature, Gravity, Density, and Moon count — displayed as bubbles positioned along a logarithmic distance axis. Bubble size and colour update instantly when switching modes, letting you compare the physical extremes of the Solar System at a glance.

This is an English HTML that visualizes the water cycle in four different ways. 01 · Live Scene — In a landscape with a sun, ocean, mountain, and river, this shows a real-time animation of water vapor rising from the ocean as the sun heats it, clouds condensing and eventually saturating to release rain over the mountain, and the river flowing back down to the ocean. The "Sun intensity" slider lets you control the evaporation rate. 02 · Process Loop — A circular diagram connecting Evaporation → Transpiration → Condensation → Precipitation → Infiltration → Runoff/Collection. Clicking each stage displays its description. 03 · Earth's Water — A donut chart showing the actual distribution of Earth's water (oceans 96.5%, glaciers 1.74%, groundwater 1.69%, surface water 0.06%, atmosphere 0.001%), based on approximate USGS figures. 04 · Stages — Each of the six stages is explained in a card with an accompanying icon.

01 · Generate Electromagnetic induction: Shows a magnet rotating next to a coil to induce alternating current (AC), visualized through animation and a live oscilloscope waveform. Adjustable via a rotation speed slider. Photovoltaic effect: Visualizes photons striking a solar panel, freeing electrons that flow through the wiring to spin a motor (fan). Adjustable via a sunlight intensity slider. 02 · Store Battery: Shows the anode/cathode and electrolyte of a chemical cell, and how the charge level drops as electrons flow through the external circuit when a load is connected. Capacitor: Using charge/discharge buttons, visualizes how charge builds up and drains between the plates (the RC time-constant curve) through field lines and a charge-level gauge. 03 · Use Ohm's law circuit: Adjusting the voltage and resistance sliders calculates the current via V=IR, with electron flow speed and bulb brightness responding in real time.

🌠 Tab 1 — Classic The core meteor shower visualisation against a night sky backdrop. Each meteor has its own independent speed, trail length, and brightness, with gradient trails that fade naturally. Includes a Milky Way band background. The Rate slider adjusts the spawn rate from 5 to 120 meteors per minute. A live counter at the bottom shows total count, currently active meteors, and estimated hourly rate. 🌍 Tab 2 — Radiant Point Visualises the perspective effect that makes all meteors in a shower appear to radiate from a single point — the radiant. Choose from four real meteor showers: Perseids, Leonids, Geminids, and Orionids. A perspective projection accelerates meteors as they move away from the radiant, just as parallel lines converge at a vanishing point. The radiant position, entry speed, and peak date are displayed for each shower. 💥 Tab 3 — Impact Simulation A physics simulation from atmospheric entry through to ground impact. Meteor colour shifts from blue-white to red as friction heats it during descent. On impact: debris fragments with gravity and restitution, expanding shockwave rings, and a crater. Three scale presets: Pebble (centimetres), Boulder (metres), and Bolide (10 metres). 🔭 Tab 4 — Spectrograph An elemental spectral analysis tool for meteors. Sliders control the emission intensity of four elements — Mg (blue-white), Na (orange), Fe (red), Ca (cyan) — and both the meteor trail colour and the emission lines in the spectrum panel at the bottom update in real time. Each line is positioned at its correct wavelength (nm) against a true-colour rainbow spectrum background. 🪐 Tab 5 — Solar System Shows the orbital mechanics behind meteor showers: Earth crossing the debris trail left by a comet along its orbit. Collision events are counted as Earth passes through the yellow debris cloud. The comet tail direction is calculated dynamically to always point away from the Sun, and Earth's orbital year is displayed in real time.

🌌 Tab 1 — Curtains Recreates the folded curtain structure of real auroras. Six glowing ribbons ripple like waves, each particle dancing with its own independent phase and velocity. Visualises how solar particles spiral down along Earth's magnetic field lines, exciting oxygen and nitrogen atoms to emit their characteristic light. 🌀 Tab 2 — Vortex The auroral corona as seen looking straight up at the magnetic pole. Particles spiral inward along converging field lines, and the Arms slider lets you adjust the spiral structure from 1 to 8 arms. Built on Float32Array typed arrays for smooth handling of 1,200 particles with minimal memory overhead. ✨ Tab 3 — Particle Storm Simulates a Kp-9 extreme geomagnetic storm — the most intense class of aurora event. Four modes: Cascade — solar particles raining down from above Explosion — particles bursting outward from a central point River — a flowing stream of particles channelled along magnetic field lines Neural — plasma connecting between nodes like a living neural network 🎵 Tab 4 — Resonance Visualises the Schumann resonance of Earth's ionosphere (7.83 Hz). Aurora particles vibrate in sync with the planet's own electromagnetic frequency. Raising the Harmonics slider adds more complex waveforms in superposition. Pulsing rings and particles move in perfect phase synchronisation. ❄️ Tab 5 — Arctic Scene A complete Arctic night scene. Twinkling starfield, moonlight glow, three-layer aurora, snow-dusted tundra silhouette, pine tree shadows, ice surface shimmer, and wind-driven snowfall — all capturing the atmosphere of Tromsø, Norway or Fairbanks, Alaska on a clear winter night.

📊 탭 1 — 핵심 확률 KPI 4개: 화석화 확률(0.00001%), 지표 노출(1/1천만), 발견·수집(1/10억), 현재 명명 종 수(~1,000종) 단계별 확률 감소 바 차트 (로그 스케일) 도트 매트릭스 2개: 1만 마리 중 화석화 1개 / 화석 1,000개 중 발견 1개 1억 마리 공룡으로 시작하는 퍼널 차트 🔬 탭 2 — 단계별 분석 사망→매몰→광물화→지각 생존→노출→파손 방지→발견까지 7단계 막대 그래프 각 단계 설명 카드 6장 서식 환경별 화석화 성공률 비교 (강·호수 85% ~ 오픈 평원 5%) 🌍 탭 3 — 지역별 발견율 대륙별 누적 발견 종 수 막대 그래프 (중국 350종 1위) 지역 카드 6장 (면적당 밀도 포함) 1824~2024년 신종 기재 누적 꺾은선 그래프 (시대별 에라 배경 포함) ⚖️ 탭 4 — 비교 시각화 공룡 화석 발견 vs 로또 1등·번개·비행기 사고 확률 로그 스케일 비교 화석 유형별 희귀도 버블 차트 (이빨~피부 인상 8종) 지질시대별 화석 발견 밀도 타임라인 (트라이아스기~백악기 후기) 🧮 탭 5 — 확률 계산기 6개 조건(서식 환경·개체 크기·뼈 밀도·퇴적 속도·경과 시간·탐사 접근성) 설정 실시간 확률 계산 및 탐사 접근성 곡선 업데이트 시나리오별 예상 확률 카드 6장 (이상적 조건~깃털 인상) 확률 계산 공식 및 참고 문헌 표시

A genealogical map of how today's Indo-European languages descend from a shared ancestor. Click any branch to expand or collapse it, or search for a language to trace its lineage back to the root.

π (pi) is the ratio of a circle's circumference to its diameter — the same number, no matter how big or small the circle. Below are four different ways people have calculated it, from ancient geometry to modern random sampling. Drag the sliders and press the buttons to see each one work.

This is an HTML page that visualizes an animated Perlin noise field in real time, styled as a terrain (contour) map. Canvas: 3D Perlin noise (x, y, time) is computed per pixel using fBm (octave summation) and mapped to terrain colors (water–sand–grassland–forest–rock–snow). Hovering the mouse over the canvas shows the noise value at that coordinate in real time. Controls: Scale, Octaves, Persistence, and animation speed sliders / Terrain·Thermal·Grayscale palette switcher / Contour bands toggle / a Reseed button to generate a new terrain.

6 Strike Modes 🖱 Click Strike — Fires a bolt from the top of the canvas to your cursor. Every click generates a unique fractal path. ✏️ Drag Path — Draw a route by clicking and dragging; bolts are generated along the entire path when you release. 💥 Multi-Bolt — One click spawns 3–5 bolts simultaneously at slightly offset positions, each with a small staggered delay. 🔗 Chain Lightning — Lightning hops through a midpoint before reaching the target, creating a relay-style chain strike. ⚪ Ball Lightning — Spawns a physics-simulated plasma orb with gravity, wall reflection, and surface sparks. ⬆️ Upward Strike — Simulates a ground-to-cloud return stroke — the actual visible flash that shoots upward in real lightning. ⚙️ Shape Controls Five sliders to fully customise the bolt shape: Jaggedness · Segments · Branching (0–0.7) · Branch length · Core width. ✨ Appearance Controls Core width · Glow radius · Flash duration · Auto interval 8 colour presets — Classic (white/blue), Gold, Purple, Green, Red, Cyan, Pink, Orange Hue shift slider for real-time colour rotation using CSS filter: hue-rotate() 🌩 Storm BG — Activates a dark cloud gradient background with 60 animated rain streaks rendered via Float32Arrays. 🔊 Sound — Web Audio API generates a low-frequency thunder rumble using a noise buffer filtered through a lowpass filter. ⌨️ Keyboard Shortcuts Space — instant strike at a random position A — toggle auto-strike C — clear the canvas G — toggle glow effect 1 – 6 — switch strike mode ↑ / ↓ — adjust jaggedness

🧱 Tab 1 — Anatomy Breaks a real prompt down into six colour-coded blocks. Click any block to open a detailed explanation in the right panel covering the component's purpose, how to write it, common mistakes, and actionable tips. 🎭 Role (purple) — persona definition 📋 Context (blue) — background information 🎯 Task (green) — the core instruction 📐 Format (yellow) — output structure 📸 Examples (orange) — few-shot samples 🚧 Constraints (red) — what to exclude Six quality score bars are shown at the bottom — Clarity, Specificity, Context depth, and more. The six technique cards below the blocks link directly to Tab 3 when clicked. ⚖️ Tab 2 — Before / After Places a weak prompt and a fully engineered prompt side by side for the same request. Four real-world scenarios included: 📧 Sales email writing 💻 Code review 📊 Data analysis ✍️ Creative writing Each pair shows actual AI response examples alongside quality tags (❌ Vague / ✅ Role defined, etc.). 🎯 Tab 3 — Techniques Eight techniques explained using a left-side navigation and right-side detail panel layout: Chain of Thought · Few-Shot · Role Prompting · Output Formatting · Self-Consistency · Tree of Thought · Iterative Refinement · Constraint Prompting Each technique includes a concept explanation, a side-by-side prompt comparison (❌ without the technique / ✅ with it), and four practical tips. 🛠️ Tab 4 — Playground Build your own prompt using four text inputs (Role · Context · Task · Format) and four technique toggles (Chain of Thought · Role Prompting · Few-Shot · Structured Output). Clicking ⚡ Build & Analyse produces: A fully assembled prompt preview with each component highlighted in its own colour A quality score (0–100) plus estimated token and word count A component checklist (✓ / ✗) showing what is present and what is missing Specific improvement suggestions — add a role, prompt too short or too long, consider CoT, and so on

☁️ 8 Cloud Types Cloud Altitude Description ⛅ Cumulus 600–2,000 m Multiple cloud clusters drifting with the wind 🌫 Stratus 0–600 m Uniform layer blanketing the entire sky 🌤 Cirrus 6,000–12,000 m Ice-crystal streaks in wispy mare's-tail shapes ⛈ Cumulonimbus All levels 8-layer towering cell with anvil top at tropopause 🌥 Altocumulus 2,000–6,000 m Grid-like pattern of rounded white-grey puffs 🌧 Nimbostratus Low–mid level Thick dark sheet producing continuous precipitation 🌁 Fog / Mist Ground level 5-layer flowing fog rendered at surface level 🔮 Mammatus Underside of Cb Hanging pouch formations (3 rows × multiple columns) 🎮 Interactive Features ☀️ Day / 🌙 Night — Toggles the sky gradient; night mode renders stars and a crescent moon 💨 Wind — 80 wind-streak particles linked to the Wind speed slider 🌧 Rain — 400-raindrop physics simulation with wind-angle deflection ⚡ Lightning — Fractal lightning bolts generated at random intervals, with higher frequency during Cumulonimbus and high-instability conditions ⏸ Pause — Freezes the animation ⚙️ Atmosphere Sliders — Temperature · Humidity · Wind speed · Atmospheric instability · Time of day (sunrise / midday / sunset / night auto-transition) 📊 Live Weather Readouts — Dew point · Cloud base altitude (LCL) · CAPE (Convective Available Potential Energy) · Visibility 🖼 Background Elements — Rolling hill silhouette + 18-tree treeline + surface fog layer tied to the humidity slider 📋 Right Panel — Per-cloud description · Step-by-step formation process · Weather forecast significance · Atmospheric layer altitude reference

🏗️ Architecture Presets (5 layouts) XOR — 2→4→1. The simplest non-linear classification example. Classifier — 4→6→6→3. Iris dataset-style multi-class classification. Deep — 3→5→5→5→5→2. A deep network for observing vanishing gradient behaviour. Autoencoder — 6→3→3→6. Bottleneck structure for dimensionality reduction. CNN-like — 6→8→8→4. Wide hidden layers resembling a convolutional network. 📐 Layer Editor — Use the Input / Hidden layers / Nodes per layer / Output sliders to build any custom architecture on the fly. ⚡ 6 Activation Functions — ReLU · Sigmoid · Tanh · Leaky ReLU · ELU · Softmax. Switching between them instantly updates the mini function plot in the top-left corner and the description in the right panel. 🎬 3 Modes Training — SGD simulation. Blue circular particles (forward pass) and red triangular particles (backpropagation) flow simultaneously while Loss, Accuracy, and Epoch update in real time. Forward pass — Only the forward-pass particles flow through the network. Backprop — Only the backward gradient particles flow toward the input. 🎨 Node colour meaning 🟢 Green — High activation (> 0.7) 🔵 Cyan — Mid-range activation 🔴 Red — Negative activation ⭕ Dashed circle × — Node deactivated by Dropout 🖱 Interactive Hover a node → tooltip showing its activation and bias values Hover a connection → weight value displayed at the midpoint Click an input node → randomises its activation and propagates the new values forward 📊 Right panel Live statistics: Epoch · Loss · Accuracy · Parameters Dual-line chart: Loss (red) and Accuracy (green) over training time Weight distribution histogram with a rainbow colour gradient Four-step Forward Pass walkthrough and activation function concept guide

10 interactive Network Effects visualizers! 📡 Metcalfe's Law — Animates every edge formed as n users connect in real time. Adjust the user count slider and the number of connections (n(n-1)/2) and network value (n²) update instantly. A comparison chart overlays the Linear, Metcalfe, and Reed's Law growth curves side by side. 📈 Adoption Curve — Rogers' technology adoption S-curve unfolds along a time axis. Adjust the tipping point position and growth rate k to visualise the exact moment of "crossing the chasm," with a five-segment adoption band (Innovators → Laggards) displayed below the chart. 🦠 Viral Spreading (SIR) — 200 particles move between S (blue), I (red), and R (grey) states as the epidemic spreads. An R₀ = β/γ gauge updates in real time — above 1 the infection spreads, below 1 it dies out. Includes an explanation of how this maps to the product K-factor. 🗂️ Network Types — Five types (Direct, Indirect, Data, Social, Local) are laid out as interactive cards, each containing a live mini network graph of its own structure. A bar chart at the bottom compares the competitive moat strength of each type. 💥 Critical Mass — A live level gauge and time-series chart show whether a network self-sustains or collapses depending on whether it sits above or below the threshold. Adjust the threshold and seed percentage to catch the exact moment a tipping point is crossed. 🏗️ Platform Competition — A pie chart and time-series graph together show how two platforms' market shares converge toward natural monopoly under network effects. Tune initial size and product quality to experiment with the conditions that trigger Winner-Take-All dominance. 🌀 Churn & Retention — A spinning flywheel diagram visualises how retention rate, viral coefficient, and new user acquisition interlock. The long-run user count trend and LTV estimate update in real time as you adjust the sliders. 🌍 Geographic Spread — Diffusion waves (expanding rings) radiate from the launch city and claim neighbouring cities one by one. A cascade effect is implemented — an adopted city shortens the adoption timer of nearby cities — letting you experience the city-by-city rollout strategy used by Uber and Airbnb. 📱 Social Network — Nodes are added in real time through invite loops, and nodes with more connections are rendered larger. The right-hand panel covers social graph growth insights including Facebook's north-star metric of "7 friends in 10 days." 🛒 Marketplace (Two-Sided) — Live transactions (yellow $ particles) flow back and forth between the buyer zone (blue) and seller zone (green), and both sides grow automatically as transactions accumulate. The right panel explains liquidity score, the cold-start problem, and the concept of rake rate.

Sorting — 6 Algorithms 🫧 Bubble Sort — Compares adjacent elements and "bubbles" the larger value to the right. Each pass is colour-coded to show the maximum value settling at the end. Live counters track comparisons (red), swaps (yellow), and sorted elements (green). 🎯 Selection Sort — Scans the unsorted region for the minimum value (blue pivot · orange current minimum) and swaps it to the front. Always performs O(n²) comparisons, but keeps the number of swaps to a minimum. 📌 Insertion Sort — Takes the next element and inserts it into its correct position within the already-sorted region. An adaptive algorithm that approaches O(n) on nearly-sorted arrays. 🔀 Merge Sort — Recursively splits the array in half, then merges the halves back together. The merge step — comparing two sub-arrays and placing elements in order — is shown as blue bars. Stable sort with a guaranteed O(n log n) time. ⚡ Quick Sort — Picks a pivot (orange) and partitions the array so smaller values go left and larger values go right, then recurses on each side. Average O(n log n), worst case O(n²). Once a pivot's final position is confirmed, it turns green. 🏔️ Heap Sort — Builds a Max-Heap from the array (heapification), then repeatedly extracts the root (maximum). In-place sort with a guaranteed O(n log n) time. Graph — 4 Algorithms 🌊 BFS — Explores outward from the start node one layer (hop) at a time. Guarantees the shortest path by hop count in unweighted graphs, then traces the route back through parent pointers once the goal is reached. 🔍 DFS — Recurses as deep as possible along each branch before backtracking. Does not guarantee the shortest path, but is the foundation for connectivity checks, topological sorting, and cycle detection. 🗺️ Dijkstra — Finds the true shortest distance in a weighted graph. A priority queue ensures the lowest-cost node is always processed first; edge weights are displayed inside each node. ⭐ A* — Dijkstra plus a heuristic (Euclidean distance to the goal). The formula f(n) = g(n) + h(n) steers the search toward the target, making it faster than Dijkstra in practice. Guarantees an optimal path as long as the heuristic is admissible.

An eleven-experiment high school chemistry lab visualiser! 🦷 Elephant Toothpaste — Raise the H₂O₂ concentration and KI catalyst sliders to watch foam erupt in real time. Includes a live reaction rate meter (%), a temperature gauge showing the exothermic heat release, and a full equation panel. 🌋 Baking Soda Volcano — Press the ERUPT! button on the 3D volcano to trigger a burst of CO₂ bubbles and flowing lava. Demonstrates the NaHCO₃ + CH₃COOH acid-base neutralisation reaction. 🟢 Polymer Slime — Click and drag to pull the slime blob around. PVA and borax sliders adjust cross-link density in real time, changing viscosity, elasticity, and stretchiness on the fly. 💡 Lava Lamp — Simulates density changes with a temperature slider. Heated wax becomes less dense and rises; it cools at the top, regains density, and sinks. Includes a "Like Dissolves Like" polarity guide and a density comparison chart. 🌈 pH Color Indicator — Sliding the pH scale from 1 to 14 shifts the red cabbage juice indicator through red → orange → yellow → green → blue → purple. Features seven reference test tubes and a table of everyday substances with their pH values. 🖊️ Chromatography — Solvent climbs the paper strip and separates six pigments according to their Rf values, with each band's Rf displayed live. Also covers five types of chromatography from paper to HPLC. 💎 Crystal Growing — Adjust concentration and temperature until the solution enters the supersaturated zone — crystals nucleate and grow in real time. The solubility curve marks your current state, accompanied by hexagonal crystal system graphics. ⚡ Electrolysis — Voltage and electrolyte concentration sliders control the rate of H₂ (blue bubbles) and O₂ (red bubbles) production at a 2:1 ratio. Animated electrode half-reactions and ion migration are shown inside the cell. 🔋 Fruit Battery — Click lemon, orange, apple, or potato tabs and stack cells in series to add voltages — the LED lights up once total voltage exceeds 1.5 V. Demonstrates the galvanic cell principle with half-reaction equations. 🧊 Endothermic Mix — Increasing the Ba(OH)₂ + NH₄SCN reagent amount drives the temperature down to −20°C, triggering a snowflake and frost animation. An energy profile diagram shows ΔH > 0. 🔥 Exothermic Reaction — Raising the Mg + H₂SO₄ concentration and temperature accelerates the reaction, spawning flame and spark particles. Includes an Arrhenius rate law visualisation and an energy profile diagram with activation energy marked.

Pre-algebra is a common name for a course taught in middle school mathematics in the United States, usually taught in the 6th, 7th, 8th, or 9th grade.

Derivative — The Slope tab Move the mouse along the curve to draw the tangent line (in red) at that point in real time A dashed secant line is shown alongside it, visually demonstrating the concept of a limit Shrink the gap between the two secant points using the Step h slider to watch it converge toward the tangent The slope angle and f′(x) value are displayed live Integral — The Area tab Drag the blue dot (a) to set the left boundary, then move the mouse to position the right boundary (b) The Riemann rectangles approximating the area are rendered step by step Increase the number of rectangles with the Rectangles slider to see the sum converge to the definite integral The ∫f(x)dx value is calculated in real time 6 available functions — sin(x), cos(x), x², x³, √x, and |x|. The absolute value function |x| is especially interesting: try hovering over x = 0 to experience a point where the derivative does not exist.

The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). https://en.wikipedia.org/wiki/Periodic_table