What is freezing fog?

Partial freezing results from trying to freeze water while preventing expansion

Within a sealed container, partial freezing of water increases the contained volume and the pressure, preventing further freezing without decreasing the temperature further. Once cooled below -23 degrees Celsius (-9.4 degrees Fahrenheit), an uncommon type of ice that contracts as it forms is produced, facilitating the complete freezing of the contained water.

Freezer burn is the result of moisture leaving ice cream

The ice cream death knell occurs when water crystals melt and then refreeze on the surface of the treat, creating a crunchy (but far from delectable) shell. The best way to prevent this unfortunate outcome is by storing your ice cream in a freezer that’s colder than 0°F.

Explaining the Leidenfrost effect, where water can hover and move against gravity

Water droplets can glide across surfaces whose temperatures are well above water's boiling point. This heat instantly vaporizes the bottom of the droplet, creating a layer of steam that the rest of the droplet rides and bounces upon. This can be seen when sprinkling water on skillets to determine if the surface is hot enough to cook on.

Hail forms in freezing temperatures thousands of feet above the ground

Even if surface temperatures are well above freezing during the summer, updrafts during thunderstorms can push raindrops high into the atmosphere, where they can freeze and form hail. Giant hailstones the size of softballs require updrafts of close to 100 mph.

Permafrost, explained.

This article explains the role of permafrost—the layer of permanently frozen soil beneath the Arctic tundra—in shaping both the ecosystem and the terrain. During the summer, the permafrost keeps the soil above it moist, which in turn impacts the...

Is ice slippery because of amorphization—a chaos of molecules caused by sliding?

Traditional explanations cite three factors that make ice slippery: pressure, friction and so-called premelting. A fourth has been proposed in recent years: amorphization, that sliding along some surfaces creates molecular disorder, causing liquid-like behavior.

How the loss of Earth's atmosphere would cause oceans to boil at freezing temperatures

Many phenomena requiring air pressure, from the flight of birds and aircraft to the act of breathing, would no longer be possible. Because sound travels through vibrating air molecules, the loss of the planet's atmosphere would also create a silent environment. Even during daytime hours, the sky would resemble a clear night sky.

The conditions needed for cloud iridescence, or rainbow clouds

The relatively rare phenomenon occurs when sunlight scatters off tiny water droplets or ice crystals in thin, newly-forming or semi-transparent clouds, such as altocumulus, cirrocumulus, lenticular, and cirrus varieties. This effect is similar to what is seen in soap bubbles and mother-of-pearl shells and produces pastel-like colors.

A history of treating frostbite

Amid Napoleon's invasion of bitterly cold Russia, soldiers succumbed to frostbite by the thousands. Nineteenth century doctors recommended walking and rubbing snow around the affected area. Fast forward to recent years, and the FDA has approved its first ever drug to treat frostbite. Listen to this podcast to learn the history of this wintry affliction.

Photochemical smog forms when sunlight reacts with car and industrial emissions

The hazy phenomenon's name is a combination of "smoke" and "fog" and is composed of chemical pollutants that can cause eye irritation, lung damage and harm to crops. Smog buildup is more common in cities with sunny climates, minimal wind and surrounding mountains that trap these chemicals.

The forgotten carnivals that stood upon the frozen River Thames

The Thames Frost Fairs were unusual winter events that took place between 1607 and 1814. They happened during the so-called Little Ice Age, when the River Thames would freeze over for up to two months straight. These unique festivals transformed the frozen river into a bustling carnival-like environment where Londoners set up temporary shops, entertainment venues, and social spaces directly on the ice.

The extremophilic origins of watermelon snow and its impact on glacial melting

Also known as "blood snow," the red coloration is produced by snow algae that thrive in extremely cold conditions and take the shape of red spherical cysts in winter. To protect themselves from more intense summer solar radiation, these psychrophiles accumulate red, orange, and yellow pigments, intensifying their coloration and causing glaciers to reflect less sunlight than if they were white.

Learn all about different types of extreme weather

Find out in more detail about different types of extreme weather, from flooding to thunderstorms, from tropical cyclones to sandstorms, and more (w/ helpful videos).

The difference between ice cream, gelato, sorbet, and Italian ice

Ice cream is made of eggs and is high in fat, served cold. Gelato, on the other hand, has more milk and less cream, and is typically served warmer than ice cream. Sorbet is dairy-free and often includes alcohol, while Italian ice is grainy, lighter, and low in calories (and often doesn't contain dairy).

Ice found in another star system for the first time

NASA's James Webb Space Telescope has discovered frozen water in a young star system. The ice is similar to that found in Kuiper Belt objects in our solar system, and provides insights into planetary formation processes.

The fish in sushi is usually frozen to eliminate parasites

Most raw fish contain parasites, but sushi restaurants and fish markets use “super freezers” to make the food safe for consumption. The United States Food and Drug Administration warns that frozen raw seafood can still contain parasites, depending on the type of fish and the conditions of the “super freezer.”

Fearology, or the study of fear, explores the difference between stress and fear

Our brains involuntarily respond to our environment and signal alarm when that isn’t always needed, triggering responses that include goose bumps. But understanding fear and how to talk our brains into calming down can improve daily life.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

What are superconductors?

Superconductors are materials that carry electrical current with exactly zero electrical resistance (move electrons through it without losing energy to heat). Read more about how they work here.

HFMD can survive on surfaces for days at a time

That's why the virus can be transmitted via fomites—surfaces that have virus on them like doorknobs, kids toys, etc. These viruses are resilient—they are often even resistant to freezing (and are frequently stored at freezing temperatures in lab settings).

What is free verse?

Free verse is a style of poetry that does not conform to any set meter or rhyme scheme. In essence, it’s poetry whose form has been created by the poet.

Fulgurites are glass sculptures made by lightning vaporizing sand

Sometimes referred to as fossilized lightning, these tube-like structures are formed when high-temperature electrical currents fuse mineral grains into crystals, which can feature branching patterns resembling filaments of current. Their name derives from "fulgur," the Latin word for lightning.

Watch an AI-generated short film

The Waymark production company created "The Frost" using the AI platform DALL-E 2. Set in an apocalyptic future where the weather has been stalled, the film was made by stitching together hundreds of clips, each only a few seconds long.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

How fermentation works

Alcoholic fermentation is the process where yeast transforms grape sugars into ethanol, creating wine. Microscopic fungi (commonly known as yeast) metabolize sugars, producing alcohol and carbon dioxide. Fermentation's speed and temperature impact wine's flavor and style: cooler temps suit fruity whites, while warmer ones enhance red's tannins. Fermentation stops when sugars are depleted or by temperature extremes, and sometimes yeast removal yields sweeter wines. Get a quick breakdown of the process with this easy explainer.

Dirty lightning is a thunderstorm created from friction between rising and falling flows of ash and smoke during volcanic eruptions.

Odor blockers use nonpolar oils to trap smelly polar molecules

In the case of feces, gut bacteria produce compounds such as skatole and hydrogen sulfide, which the brain registers as unpleasant. Because oils do not dissolve in water, they can be used to create a layer on the surface that prevents smelly compounds underwater from escaping into the air.

What is the Fediverse?

The "fediverse" is a league of like-minded apps looking to make our digital identities—including posts, followers, activity—move seamlessly between networks. It's a decentralized approach, making various social networks interoperable in contrast to Facebook and Twitter, where content is platform-specific. The fediverse provides stability and control to users. Learn more here.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Shooting stars, or meteors, are fragments of asteroids and comets that burn up as they enter Earth's atmosphere, creating streaks in the sky called meteor showers.

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

View the ten deadliest tornadoes in US history.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

The United States has had a tumultuous relationship with Cuba since its 1959 revolution, highlighted by a nuclear crisis and a decades-long trade embargo.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.