https://flashscience.org/ Carefully sourced science explainers that take one mechanism at a time and explain it properly. en © 2026 Flash Science contact@flashscience.org (Sok Heng Oeun) contact@flashscience.org (Sok Heng Oeun) Mon, 24 Aug 2026 09:00:00 +0000 https://flashscience.org/how-does-camera-autofocus-find-a-sharp-image.html https://flashscience.org/how-does-camera-autofocus-find-a-sharp-image.html See how contrast and phase detection measure blur, move lens groups and track subjects—and why blank walls, darkness and motion make autofocus fail. Technology & Engineering Sok Heng Oeun Thu, 20 Aug 2026 09:00:00 +0000 https://flashscience.org/how-do-undersea-internet-cables-carry-the-world-s-data.html https://flashscience.org/how-do-undersea-internet-cables-carry-the-world-s-data.html Follow Internet data through a landing station, optical fibre and powered repeaters to a deep-sea repair — and why ocean distance makes some latency unavoidable. Technology & Engineering Sok Heng Oeun Wed, 19 Aug 2026 09:00:00 +0000 https://flashscience.org/a-day-on-venus-outlasts-its-year.html https://flashscience.org/a-day-on-venus-outlasts-its-year.html Venus takes about 243 Earth days to rotate but only 225 days to orbit the Sun. The headline is true—depending on what ‘day’ means. Space & Astronomy Sok Heng Oeun Tue, 18 Aug 2026 09:00:00 +0000 https://flashscience.org/how-does-password-hashing-protect-accounts.html https://flashscience.org/how-does-password-hashing-protect-accounts.html See how salts, slow password hashes, work factors and optional peppers limit database-breach damage—and why hashing cannot stop phishing or reused passwords. Technology & Engineering Sok Heng Oeun Mon, 17 Aug 2026 09:00:00 +0000 https://flashscience.org/why-is-the-sky-blue.html https://flashscience.org/why-is-the-sky-blue.html The sky is blue because tiny air molecules scatter short blue wavelengths of sunlight far more than longer red ones, spreading blue light across the whole sky. Earth & Environment Sok Heng Oeun Sun, 16 Aug 2026 09:00:00 +0000 https://flashscience.org/how-does-an-led-produce-light.html https://flashscience.org/how-does-an-led-produce-light.html Follow electrons and holes through an LED, calculate photon energy, see how blue LEDs make white light, and learn why efficient lamps still get hot. Technology & Engineering Sok Heng Oeun Sat, 15 Aug 2026 09:00:00 +0000 https://flashscience.org/why-is-the-ocean-salty.html https://flashscience.org/why-is-the-ocean-salty.html The ocean is salty because acidic rain dissolves minerals from rock and rivers carry them to sea, where salt builds up to about 3.5% and stays steady. Earth & Environment Sok Heng Oeun Fri, 14 Aug 2026 09:00:00 +0000 https://flashscience.org/how-does-a-computer-chip-use-ones-and-zeros.html https://flashscience.org/how-does-a-computer-chip-use-ones-and-zeros.html See how voltage ranges, CMOS transistors, logic gates, memory and clocks turn analog physics into reliable binary computation. Technology & Engineering Sok Heng Oeun Thu, 13 Aug 2026 09:00:00 +0000 https://flashscience.org/why-does-the-moon-cause-tides.html https://flashscience.org/why-does-the-moon-cause-tides.html The Moon's gravity stretches Earth's oceans into two bulges, and as the planet spins beneath them we get two high and two low tides a day. The Sun helps too. Earth & Environment Sok Heng Oeun Wed, 12 Aug 2026 09:00:00 +0000 https://flashscience.org/how-do-the-northern-lights-glow.html https://flashscience.org/how-do-the-northern-lights-glow.html Aurora colors come from excited oxygen and nitrogen—not colored solar wind. See why altitude, atomic lifetime and camera exposure change the sky. Space & Astronomy Sok Heng Oeun Tue, 11 Aug 2026 09:00:00 +0000 https://flashscience.org/why-does-earth-spin.html https://flashscience.org/why-does-earth-spin.html Earth spins because it inherited angular momentum from the spinning cloud it formed in 4.5 billion years ago. With almost nothing to slow it, it just keeps turning. Space & Astronomy Sok Heng Oeun Mon, 10 Aug 2026 09:00:00 +0000 https://flashscience.org/why-moon-shows-same-face.html https://flashscience.org/why-moon-shows-same-face.html See why the Moon must rotate to keep one face toward Earth, how tidal torque created synchronism, and why libration reveals more. Space & Astronomy Sok Heng Oeun Sun, 09 Aug 2026 09:00:00 +0000 https://flashscience.org/why-do-we-have-seasons.html https://flashscience.org/why-do-we-have-seasons.html Seasons come from Earth’s ~23.4-degree axial tilt changing the angle of sunlight and length of day, not from the planet’s distance to the Sun. Earth & Environment Sok Heng Oeun Sat, 08 Aug 2026 09:00:00 +0000 https://flashscience.org/how-black-hole-traps-light.html https://flashscience.org/how-black-hole-traps-light.html Learn why light still moves locally at c near a black hole, while curved spacetime removes every future-directed route from inside the event horizon. Space & Astronomy Sok Heng Oeun Fri, 07 Aug 2026 09:00:00 +0000 https://flashscience.org/why-do-onions-make-you-cry.html https://flashscience.org/why-do-onions-make-you-cry.html Onions make you cry because cutting them releases enzymes that build a volatile tear-inducing gas. Learn the chemistry — and how to stop the tears. Life & Chemistry Sok Heng Oeun Thu, 06 Aug 2026 09:00:00 +0000 https://flashscience.org/how-do-caves-form.html https://flashscience.org/how-do-caves-form.html See how weakly acidic groundwater enlarges fractures, why stalactites arrive later, and how sulfuric acid, lava, waves and ice form other caves. Earth & Environment Sok Heng Oeun Wed, 05 Aug 2026 09:00:00 +0000 https://flashscience.org/what-would-happen-if-earth-stopped-spinning.html https://flashscience.org/what-would-happen-if-earth-stopped-spinning.html If Earth stopped spinning suddenly, everything would keep moving at up to 1,600 km/h. Even a gradual stop would bring six-month days and a reshaped world. Space & Astronomy Sok Heng Oeun Tue, 04 Aug 2026 09:00:00 +0000 https://flashscience.org/how-do-clouds-stay-in-the-sky.html https://flashscience.org/how-do-clouds-stay-in-the-sky.html Cloud droplets do fall—but often only centimeters per second. See how drag, updrafts, condensation and particle growth keep a cloud visible. Earth & Environment Sok Heng Oeun Mon, 03 Aug 2026 09:00:00 +0000 https://flashscience.org/what-if-the-sun-disappeared.html https://flashscience.org/what-if-the-sun-disappeared.html A physics thought experiment: if the Sun vanished, Earth would keep light and gravity for ~8 min 20 sec, then fly off in a straight line and slowly freeze. Space & Astronomy Sok Heng Oeun Sun, 02 Aug 2026 09:00:00 +0000 https://flashscience.org/how-does-a-hurricane-grow.html https://flashscience.org/how-does-a-hurricane-grow.html A hurricane grows through a fragile ocean–atmosphere feedback. Follow moisture, latent heat, pressure and rotation—and see why warm water is not enough. Earth & Environment Sok Heng Oeun Sat, 01 Aug 2026 09:00:00 +0000