Kayf vs HOW?

Kayf is an illustrated encyclopedia of how things work. Pick any device, from the fan on your desk to the refrigerator, the microwave, your phone, a car engine, a wind turbine or an MRI scanner, and open it up. See every part, what it is made of and what it does. Then follow the animated step-by-step sequence of how the device actually works, with each part lighting up as it plays its role. 100 DEVICES IN 8 CATEGORIES - Home appliances: fan, refrigerator, air conditioner, washing machine, vacuum cleaner, water heater, iron, hair dryer, dishwasher, dryer, sewing machine, dehumidifier - Kitchen: microwave, kettle, blender, toaster, espresso machine, induction cooktop, gas stove, pressure cooker, rice cooker, air fryer, oven - Electronics: LED bulb, loudspeaker, microphone, noise-cancelling headphones, camera, television, remote control, lithium battery, electric motor, transformer, smartwatch, wireless charger - Computing and communication: smartphone, touchscreen, Wi-Fi router, processor, SSD and hard drive, printer, GPS, barcode scanner, fiber optics, Bluetooth, LiDAR scanner, NFC reader and tag - Transport: car engine, electric car, bicycle, jet engine, helicopter, how planes fly, ABS brakes, submarine, drone, elevator, escalator, traffic light, hydraulic excavator, liquid-fuel rocket engine - Energy: solar panel, wind turbine, hydroelectric dam, nuclear reactor, generator, power grid, gas power plant, desalination, UPS, geothermal, hydrogen fuel cell - Everyday mechanisms: lock and key, toilet flush, mechanical watch, zipper, bicycle pump, thermostat, smoke detector, doorbell, digital scale, ballpoint pen, aerosol can, fire extinguisher, faucet, 3D printer, power drill, industrial robotic arm - Medical and science: X-ray, MRI, ultrasound, blood pressure monitor, stethoscope, pulse oximeter, infrared thermometer, microscope, pacemaker, defibrillator, telescope, CT scanner FOR EVERY DEVICE - Interactive exploded view: tap a part to learn its role and material - Animated how-it-works sequence, step by step - The science: several paragraphs on the physics and the design choices - By the numbers: power, speed, temperature, efficiency, lifespan - Surprising facts, types and variants, safety notes - Related devices and the principles they share ALWAYS-FREE ENGINEERING LAB - What If Lab: make predictions and explore motor, wind and compression models with live graphs - Fault Detective: inspect virtual measurements and identify a fault - Assembly Bench: solve a five-part fan assembly puzzle THE PHYSICS - 36 principles from electromagnetic induction to Bernoulli, each explained with a formula and everyday examples and linked to every device that uses it - A glossary of 162 technical terms in plain words KAYF PRO (one-time purchase) - All 100 devices - Troubleshooting guides: real symptoms, likely causes and what to do - Every quiz: five questions per device, category quizzes and the mixed challenge - Compare two devices side by side Paid features also offer one-visit trials through optional rewarded ads. A new visit or paid quiz replay requires a new ad. Ads need an internet connection and available inventory. Monthly drops keep their release schedule. Automatic App Store update checks with a manual check in Settings. Fully in English and Arabic with true right-to-left layout. No account needed, and all content works offline. The free version shows ads; Kayf Pro removes them. Kayf is an educational reference. Always follow the manufacturer's manual and a qualified technician for repairs.

Discover the mechanisms hiding inside everyday objects. A wheel, a computer mouse, a pair of scissors: you use them without thinking. HOW? invites you to look closer, with a daily discovery told through interactive exploded-view drawings. GUESS FIRST Start with a question and make your guess. Then reveal the answer and explore the mechanism behind it. TAKE IT APART Follow the numbered steps as the drawing comes apart. Each highlighted piece has a job: see what it does and how it works with the others. Try the interactive controls to explore further. BUILD YOUR LIBRARY Return to previous discoveries and look at familiar objects with fresh eyes. CHOOSE WHAT COMES NEXT Suggest an object you are curious about and vote for topics you would like to see explained. HOW? is free, with no account required, no subscriptions and no in-app purchases. Available in English and French, with light and dark appearances and optional reminders. One object. A few parts. Something new to understand.