High-frequency sound waves have been used to brew espresso with room-temperature water and about one-fourth the energy of a traditional espresso machine, which relies on hot water and pressure.

Slow pour-over coffee resists the haste of 'espresso' and commodification of drip

Pour-over coffee involves what its name suggests: slowly pouring hot water from a gooseneck kettle over a funnel of ground coffee, usually requiring at least 3 minutes. This trend developed in the 1970s in opposition to on-demand drip coffee and "espresso," literally invented as an "express" option to save time.

Different brewing methods require different grinding methods

With so many brewing methods—AeroPress, Moka Pot, and French press to name a few—knowing the right grind size for your coffee beans is essential. Danish coffee expert Asser Christensen, also known as the Coffee Chronicler, explains how grinding works and recommends the best grind choice for different coffee makers.

Ultrasound machines emit and receive high-frequency sound waves to construct images of the body's interior, with differences in the penetrating power of different frequencies allowing medical professionals to identify different structures.

Interacting sound waves can create regions where the pressure from each wave combines, allowing objects to levitate in place against gravity or be manipulated for touch-free construction.

Coffee contains an average of 15mg of caffeine per fluid ounce

Coffee has three times the amount of caffeine contained in most caffeinated sodas, but significantly less than espresso and cocoa powder.

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

Objects that move faster than the speed of sound—Mach 1—create shockwaves called sonic booms by building up and forcing sound waves to combine as they lag behind the object.

Understand distinctions between coffee types and other popular cafe beverages with this visual guide.

Some geothermal power plants make electricity using a secondary fluid

Direct dry-steam systems pull underground steam into a turbine-generator system, while flash and double-flash cycle systems spray extracted liquid water into a low-pressure tank, causing it to rapidly vaporize—"flash"—before moving to the turbine. Binary cycle systems use the extracted steam and water to flash a second fluid that easily boils, which then drives the turbine.

Water vapor is used to manage heat in high-end smartphones

While smartphones have traditionally been cooled using a highly conductive plate that dissipates heat from the chip, vapor chambers offer a higher heat-removal capacity. This technology has been utilized in laptops for decades to absorb heat by cycling a fluid between liquid and gaseous phases.

Microwave ovens heat food by agitating certain molecules with non-ionizing light

Molecules with resonant frequencies within the microwave range vibrate, producing heat between adjacent matter, just as hands warm when rubbed together. The mesh in front of an oven's door confines the microwaves to the container, while the rotating plate allows different parts of food to travel through regions of maximum vibration.

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.

The benefits of sous vide: cooking food in bags immersed in water

Through this technique, food can be prepared to precise temperatures lower than those of open flames, without the risk of overcooking, with less oil, fat, and salt, and without requiring ongoing attention. By allowing for long cooking times, tougher cuts of meat can also be prepared at lower temperatures.

How to cook food with lasers

Creative Machines Lab at Columbia Engineering have developed a system of software-controlled lasers to cook food with precision, retain moisture with the final-cooked product, brown food within its original packaging, and create an entirely new meal creation process for a consumer. Watch this three-minute video to see for yourself.

Coffee brewing likely originated in Ethiopa and the Arabian Peninsula

A mixture of merchants and colonialism then launched the drink across Europe and the New World. Many European coffee traditions, like the Viennese custom of serving it alongside a small cup of water, are remnants of how coffee has been prepared in the Middle East for centuries.

Since 2026, the Large Hadron Collider has provided heat to thousands of French homes and businesses through a system that harnesses hot water from the accelerator's cooling circuits.

Geothermal power can generate electricity and provide direct heating for homes

By drilling several kilometers through penetrable rock, wells can access highly pressurized groundwater warmed by thermal energy trapped beneath Earth's surface. This water can be turned into steam to create electricity in generators. Heating systems several meters deep can pump fluid underground before circulating it through buildings.

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.

Although PFAS, or forever chemicals, are intentionally designed to be extremely stable and long-lasting because of their strong carbon-fluorine bonds, these bonds can be broken by heat, plasma, and supercritical water.

By igniting flammable gas in a tube filled with holes and playing music into it, the fire will take the shape of the sound waves, enabling the visualization of audio.

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.

Some materials can absorb low-energy light and emit high-energy radiation

Through anti-Stokes cooling, incoming energy is combined with vibrations in a material's crystal lattice to produce a net reduction in its temperature. Using this effect, lasers can be directed at microchip hot spots to help keep data centers cool.

Desalination involves costly, energy-intensive methods for producing freshwater

Thermal desalination heats saltwater to produce steam, and reverse osmosis forces saltwater through a membrane that only allows water through. In both cases, freshwater is collected and remineralized for consumption, while wastewater brine is often returned to the ocean, where it may harm marine organisms.

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.

Enhanced geothermal power systems can trigger earthquakes by injecting fluid into rock, increasing subterranean pressure.

Within an anechoic chamber, all surfaces are covered with specialized materials that prevent wave reflection, helping prevent sound from echoing in the space.

Fracking technology can help make geothermal power possible almost everywhere

Generating electricity from Earth's thermal energy has previously required existing underground reservoirs of hot water and permeable rocks through which the fluid naturally escapes. Today, fractures can be artificially created to form fluid pathways, and surface water can be injected underground and brought back to the surface.

Through sonoluminescence, concentrated sound waves can produce short, high-intensity flashes of light by rapidly collapsing microscopic bubbles to temperatures up to twice that of the sun's surface.

Geothermal power can be used beyond heating and energy production

Depending on the depth of the natural vents or artificial wells drilled, the surrounding fluid temperature will vary greatly—from 10 to 371 degrees Celsius (50 to 700 degrees Fahrenheit)—allowing for various applications, including the drying of cement, concrete, and lumber, as well as the processing of pulp and paper.

Roasting controls how your coffee will taste

James Hoffmann, winner of the 2007 World Barista Championship, is the best person to break down the importance of the roasting process. Arguably, along with where beans are grown, roasting is the most important variable in the flavor of your favorite drink.

Beanless 'coffee' is an eco-friendly alternative

As we consider the role of agriculture in climate change, many people are seeking alternatives to the most resource-hungry crops—coffee included. Are new synthetic alternatives the answer? Startups are exploring beanless “coffee” made in a variety of ways.

Aquifer thermal energy storage systems bank water heated during the summer in aquifers—layers of porous rock, gravel, and sand filled with groundwater—which are then collected in winter to warm homes.

The American Heart Association says adults can safely drink up to five cups of coffee per day and regular consumption may improve cardiovascular health.

Cultivate your coffee taste with this interactive flavor wheel

Coffee is one of the more complex things humans consume, and taste can vary drastically based on bean genetics, roasting technique, and more. Using this flavor wheel, you can more accurately describe your coffee's aroma by starting from the center and moving outward.

Washing dishware before putting it in a dishwasher may reduce the appliance's effectiveness because it dynamically adjusts wash time and temperature based on a sensor that detects dirtiness.

Why the James Beard Awards finally recognized a coffee professional

Jack Benchakul is the sole coffee maker at Los Angeles' Endorffeine and the first in the coffee world to be recognized by the prestigious food and drink awards. His attention to detail mirrors the level of craft cocktail makers whom the awards have historically praised.

Coffee is made by brewing the seeds from the coffeea plant

The cherries from the coffeea plant are milled into coffee beans. After processing, the beans are dried and roasted.

A person's voice sounds different when breathing helium, sulfur hexafluoride, or gases other than air because the speed of sound varies with the properties of the material through which it travels.