Under certain conditions, very hot liquids can freeze more quickly than cooler ones—a phenomenon called the Mbemba effect, after the Tanzanian high school student who accidentally observed it.

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.

If the temperature of water continuously decreases but it is not given room to expand, it will eventually contract and form exotic forms of ice that would sink in liquid water.

Freezer burn is the result of moisture leaving ice cream, something that's easily avoidable.

High freezing speed restricts the development of gritty crystal chunks in ice cream

For this reason, ice cream does not maintain its smoothness when refrozen in a traditional freezer over several hours. The smooth texture is also made possible by balancing fat, sugar, and emulsifiers.

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.

What is freezing fog?

Freezing fog is a weather condition in which fog containing supercooled water freezes on contact with objects, forming a layer of ice and possibly dangerous driving conditions. Get the breakdown with this explainer.

Temperatures colder than Pluto can allow electricity to flow resistance-free

Since its discovery in 1911, applications of superconductivity have made MRI machines and maglev trains possible due to quantum effects at extreme temperatures. These effects are modeled as electrons cooperating in pairs and flowing more efficiently.

Fish in polar waters contain proteins in their blood that act as antifreeze, and some manufacturers have used lab-grown versions of these proteins to help keep ice cream smooth.

A look at hydrothermal vents, where barophiles and hyperthermophiles survive boiling water

Discovered in 1977 during an exploration of the Galapagos Rift, these seafloor openings spew hot magma and chemicals that heat seawater to hundreds of degrees. Without the sunlight found at depths of less than 1,000 meters (3,281 feet), extremophiles in these environments convert released chemicals into energy to survive, alongside surviving extreme pressures.

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.

How freeze-drying leaves food with less than 4% of its original water content

In specialized equipment, foods are brought down to temperatures below freezing before a vacuum pump removes the air from the container, lowering the pressure around the food and the boiling temperature of water. Heaters beneath the food slowly raise its temperature above the now-reduced boiling point, causing the water to go from a frozen to a gaseous state.

Watch a server submerged in a fluid continue to run and stay cool by boiling the liquid away.

Different types of ice link water molecules together in unique shapes

The ice used to cool drinks—Iₕ—is composed of H₂O molecules arranged in hexagonal structures. This structure forms as ice expands during freezing, providing additional space between molecules, lowering the overall density, and allowing it to float in water. Under sufficient pressure, this spacing can collapse in many ways, creating new forms of ice.

Simulations suggest ice's slipperiness comes from rearranging molecules

Past models have proposed that slipperiness arises from a thin layer of liquid water formed at the ice's surface by frictional melting. However, new research suggests that electromagnetic forces between interacting surfaces push water molecules out of an ordered, crystalline structure and into a shapeless, soft, slippery layer. This process occurs solely through contact, independent of pressure or friction.

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.

Our bodies cool us down by sweating because water requires a significant amount of energy to change state from liquid to gas, making it an ideal medium for carrying thermal energy away from our bodies.

A guide to making ice cream with liquid nitrogen by flash-freezing dairy

Only existing in liquid form at extremely low temperatures, nitrogen can rapidly freeze cream, coconut milk, and other liquids into small crystals, producing smooth, creamy ice cream. As a safety precaution, liquid nitrogen should be handled in a well-ventilated area with safety goggles and protective gloves.

The greenhouse effect was discovered by analyzing Earth's temperature

Using mathematical techniques developed to analyze heat transfer, Jean-Baptiste Joseph Fourier showed that Earth should be significantly cooler if solar radiation were the only contributor to its surface temperature. By considering that the atmosphere could amplify the sun's warming effect, he formulated what became known as the greenhouse effect.

'Watermelon snow'—patches of pink, orange, and red in snow—is the result of extremophilic green algae that thrive in extremely frigid conditions and take the shape of red spheres in winter.

If two strands of conducting materials are connected at two junctions, electricity can be generated if one junction is heated while the other is cooled—a phenomenon known as the Seebeck effect.

Extreme temperature resilience appears to be temporary for tardigrades

Although often considered indestructible, scientists observed these creatures could endure temperatures near 150°C for only a few minutes in their tun state. Outside this state, only half the samples in a Danish study survived 37.1 degrees Celsius (98 degrees Fahrenheit) for 24 hours, making tardigrades extremotolerant rather than extremophiles.

Viscosity is a fluid's resistance to flow, which varies with temperature

Liquids become less viscous as temperature increases, while gases become more viscous and therefore flow more slowly. The increased gas collisions at higher temperatures contribute to greater friction between streamlines, increasing viscosity.

In 2009, accidentally drilling into magma provided time capsules of volcanic glass

While drilling for geothermal energy in Iceland's Krafla Geothermal Field, magma encountered at a depth of 2,100 meters quickly formed glass upon making contact with drilling fluid. By trapping dissolved gases, volatile chemicals, and the physical characteristics of magma before cooling, the glass acts as a time capsule of ancient volcanic activity and magmatic conditions.

Heatstroke treatment guidelines were built almost exclusively on research in men

Protocols for the standard treatment recommendation for heatstroke—whole-body cold water immersion—were built based on studies almost entirely in men. The research wasn't replicated in women, who typically cool faster than men during cold water immersion, raising questions about standard protocol safety for women, due to the risk of overcooling.

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.

Cold water swimming can induce positive stress

The tradition of cold water swimming (or taking a cold plunge, or even a cold shower) has been shown to release the same hormones triggered during a stress response. This can have the effect of increasing blood flow, improved mental acuity, and more.

Reduced inflammation from cold plunges lacks scientific support

The cold water triggers immediate cold shock, increasing heart rate and blood pressure, and prolonged exposure can lead to cold-water incapacitation and hypothermia. Plungers are encouraged to enter the water slowly and manage their breathing to reduce the risk of shock. Warm baths post-plunge are discouraged, and exercise is generally better for recovery.

There may be 74,963 kinds of ice, resulting from water molecules rearranging themselves

The theoretical limit greatly expands the known types of ice, with type Iₕ being the most common on Earth and forming hexagonal crystals. The extreme environments of planets like Uranus and Neptune can create a variety of ice with unique structures and properties, as these conditions can reshape these crystals into new geometries.

Webb's sunshield enables extreme cooling for precision space observation

To avoid interference from its own heat, the telescope uses a five-layer shield to stay ultra-cold and stable, allowing its instruments to function at cryogenic temperatures. One instrument, MIRI, gets so cold it needs a helium-powered cooler to reach just 7 Kelvin, or -447°F.

Watch a demonstration of the greenhouse effect with carbon dioxide, where thermal energy is trapped by the gas within a container, causing the temperature to increase.

Temperature is a value that controls how predictable or creative an LLM's output is

In large language models, temperature adjusts the randomness in text generation by modifying how often words with lower probabilities are selected next in the sequence. Lower temperatures produce more obvious outputs while higher temperatures produce more creative responses.

Feels-like temperature indicates how our skin will feel

When the wind is moving faster, we tend to feel colder due to the so-called "wind chill," which cools our bodies by moving heat away from them and making water evaporate faster. On the other hand, high levels of humidity can make us feel 10 degrees warmer at times.

Data centers can be kept cool by circulating fluid over plates atop high-temperature components or by submerging equipment in non-corrosive oil that does not conduct electricity.

Validation of the greenhouse effect may have been misattributed

Although Irish physicist John Tyndall showed in 1859 that water vapor and carbon dioxide could absorb and radiate infrared radiation, experiments by American scientist Eunice Foote three years earlier identified the same phenomenon for light in general. Historically overshadowed, her work was rediscovered by female historians over a century later.

Ice cream’s unfrozen consistency is thanks to sugar

Making ice cream is a complex, multistep scientific process. But the treat’s scoopable, chewable consistency is due to the product’s dissolved sugar.