Concrete is made of water, a fine aggregate such as sand, a coarse aggregate such as gravel, and cement, which is a fine binding powder composed of limestone, clay, shells, and silica sand.

Roman concrete lasts longer than modern recipes—and even gets stronger

Today's concrete is made by binding ingredients, including chalk and silica sand, at high temperatures. Unfortunately, it weakens when exposed to salt water. This article explores how and why scientists are studying ancient Roman concrete, which grows stronger when exposed to salt water.

Local limestone made waterproof cement for the Erie Canal

In 1818, engineer Canvass White discovered that limestone near Chittenango, New York, could be processed into hydraulic (or waterproof) cement. This breakthrough replaced costly European imports, enabling watertight locks and aqueducts and revolutionizing American construction.

Nearly all of China's construction sand is artificial

Roughly 50 billion tons of sand are used in construction every year, mostly extracted from oceans, beaches, and rivers. To avoid depleting natural sand deposits, China crushes rocks and used materials to create an artificial sand, which it uses in 80% of its construction projects.

Where does your glass come from?

Glass is created from silica sand, soda ash, and limestone. The more transparent you want your glass to be, the higher the purity you need from your silica—a rarity. Colorless, low-iron glass featured in skyscraper windows and Apple's cube-shaped showrooms has increased demand for such pure silica.

Diamonds have been made from substances such as peanut butter and carbon dioxide, though they can be created from any carbon-rich material under extreme pressure and temperature.

A breakdown of gelling agents used to modify a liquid's texture

Gelatin, agar, and other substances form a structural network that traps liquid, making it appear solid and enabling chefs to create stable layers in pastries and confectionery products. In different concentrations, they can also be used to thicken liquids into gels or encase them in gelatinous spheres.

The composition of magma affects the explosivity of volcanic eruptions

Silicate-rich magma contains extensive molecular chains that trap dissolved gases like water and carbon dioxide. These gases build pressure until they violently escape, creating explosive eruptions. Low-silica magmas produce gentler eruptions categorized as effusive.

The ancient engineers inspiring modern building practices

Modern concrete structures need replacing every 50 to 100 years, so why are buildings by the Maya, ancient Rome, and ancient China still standing strong? This article details how scientists are looking into humanity's past for clues on how to craft long-lasting structures. Part of the problem is adopting old material recipes to hold up to modern demands.

Stony corals form a type of calcium carbonate called aragonite from ions brought to the ocean by rivers that have broken down terrestrial rocks.

Cloud formation requires water vapor and condensation nuclei to build from

The nuclei—particles like dust, salt, and smoke—act like jumpstarts that water molecules can start to accumulate onto to form clouds. Condensation nuclei are about 1/100th the size of cloud droplets, which are mostly water.

Additive manufacturing consists of seven different process categories

Although 3D printing has become synonymous with the term, objects can be fabricated without filaments of hot plastic or light-sensitive powders. For example, during sheet lamination, ultrasonic waves—high-frequency vibrations—can join metal sheets by creating molecular bonds through friction.

Volcanic activity can lead to the formation of fertile soils

Ejected rock can introduce key minerals found in fertilizers, including iron, magnesium, and potassium, to improve soil quality. Ash and basalt crystals can be easily absorbed into soils, infusing them with sulfur, oxygen, chlorine, phosphorus, calcium, and other critical elements.

Explore the chemical compounds found in fireworks

Besides the various salts and metals used to produce fireworks colors, shells are also filled with gunpowder and oxidizers to help fuel and accelerate reactions. Chlorates help strengthen colors, while dextrin, a starch, helps hold mixtures together.

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.

Minerals, crystals, rocks, and gems explained

Have you ever wondered what differentiates a mineral from a rock or a crystal from a gem? This three-minute video from the American Museum of Natural History elaborates on the unique properties and compositions that separate minerals, rocks,...

Glass can be endlessly recycled without losing quality

Sand from specialized mines is thoroughly cleaned and melted at more than 1,600 degrees Celsius before being poured onto liquid tin and evenly spread out to form glass sheets. Some factories are designed to reprocess 100% of glass scraps created when cutting glass with diamond-tipped blades or lasers.

How chemical bonds between atoms form molecules and large geometric structures

In ionic bonding, one atom transfers at least one electron to another atom, forming two atoms of opposite charge. These atoms attract one another and can stack up in a 3D grid called a lattice. Covalent bonding, where electrons are instead shared, can produce enormous molecules, such as the two found in human chromosome 13, which each contain 37 billion atoms.

Engineering tall structures requires managing wind, earthquakes, and other destabilizing factors

Reinforced concrete, energy dampers, braced frames, flexible structures, and aerodynamic decks were among the methods implemented when building structures such as the Shanghai Tower, the Texas Super Skyscraper, and the South Rangitīkei Viaduct.

Volcanic ash is composed of fragments of volcanic rock, minerals, and glass

These abrasive particles are hazardous to aircraft. They can melt within engines and re-solidify on turbine blades, preventing forward propulsion. If inhaled, chemicals within ash can be toxic, and the particles can embed themselves into the lungs' ducts, causing suffocation.

Silicon must be 99.9999999% pure to be used in creating microchips

After the mined quartz is processed in an electric-arc furnace to remove oxygen from the silica, it undergoes the Siemens process, where it is bathed in hydrochloric acid. The liquid produced in the reaction undergoes multiple distillations to produce ultra-pure silicon in the end.

Geode formation begins with trapped gas bubbles in igneous or sedimentary rock

Over thousands or millions of years, water seeps into the cavity created by the bubble and deposits minerals, which slowly build and crystallize into quartz, agate, amethyst or other crystals.

Clouds can be categorized into 10 basic types based on their height and composition.

Among the features of these types, cirrus clouds can display various colors at sunrise and sunset, while altocumulus clouds can produce a corona phenomenon around the sun or moon. Nimbostratus clouds are thick enough to block out the sun entirely.

The ingredients that make up severe weather

A seven-minute video illustrating how a storm is made. These factors—moisture, instability, lift, and shear—are explained through a series of data sets and creative, descriptive diagrams.

The ancient uses of asphalt

Asphalt is derived from bitumen, a naturally occurring byproduct of decomposed organic materials. As one of the thickest forms of petroleum, the substance has been in use by humans and their ancestors for at least 40,000 years for various purposes, including as a sealant, an adhesive, decoration, and more. Learn more about this ancient material here.

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.

Jam and jelly differ in texture because of how fruit is processed

Jam contains crushed fruit with preserved pulp and fibers for a thicker, spreadable texture. Jelly is made from filtered fruit juice and produces a smooth, translucent gel. The distinction reflects preservation methods developed to extend fruit shelf life while tailoring texture and appearance.

Lava flow viscosity plays a significant role in the type of volcano formed

Thin, runny flows spread quickly before cooling, producing expansive layers that build over time into wide shield volcanoes. The ejection and fast hardening of thicker lava flows and pyroclastic material create steep slopes and the characteristic cone shape of composite volcanoes.

Water is naturally tinted with a slight blue, but sediments and organics can alter its color

The innate coloration comes from water absorbing red light in the visible spectrum more than green or blue, giving shallow waters in some parts of the Caribbean their turquoise hue. If sand is light, it can be churned up by turbulent water, clouding its appearance. Plankton and other organisms can color water by affecting how the rest of the spectrum is absorbed or reflected.

The three types of coral reefs—fringing, barrier, and atoll—are categorized by where they form.

Explaining concentrate and how concentrate-derived juice differs from its source

Developed to reduce the volume of goods—thus lowering storage and shipping costs—the concentration process uses pressure and heat to remove water, pulp, and skin from fruits. Concentrates provide significant flavor, sugar, and calories to foods in small quantities, but do not retain most of the fiber, vitamins, and other nutrients from the source fruit.

What's inside an Oreo?

If you look at the ingredient list on your Oreo packaging, you may discover that you don't recognize—or can't even pronounce—some of the listed ingredients, let alone know what they're used for! For instance: Did you know that soy lecithin helps makes oil and water mix? Or that cocoa processed with alkali becomes darker and less acidic? A food scientist breaks down what's inside an Oreo in this seven-minute video.

How are scientists turning deserts into farmland?

This article explores how engineers are using a liquid nanoclay solution to transform barren deserts into productive fruit farms, drawing inspiration from how clay particles carried by floodwaters in the Nile Delta used to improve the fertility of...

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.

The three theories explaining how the pyramids were built

There's no consensus over how the ancient monuments were built, and no blueprints left behind. But centuries of study have produced three competing theories: a simple, massive external ramp, a more complex internal ramp, or a highly sophisticated water elevator.

Scientists can determine Earth's past environmental conditions by analyzing sediment cores—accumulated layers of mud and remains of charcoal, pollen, plants, algae, and other organic material.

Modern landfills use layered liners, leachate systems, and gas monitors to safely contain waste

Today, landfill engineering is far more complex than a hole in the ground, which was largely the system cities used less than a century ago. This video explains how it actually works.

View a sample of objects surprisingly derived from crude oil, including chewing gum and lipstick

Crude oil processing produces a variety of fuels and the building blocks for plastics, but it also distills out the hydrocarbons used to make aspirin, Teflon, vinyl, crayons, candles, Tupperware, roofing shingles, asphalt pavement, hair dye, anesthetics, food-grade lubricants, polyester, synthetic rubber, and resins for items like dentures.

Stonehenge was built using giant wooden rollers and precisely carved tongue-and-groove joints to lock the stones in place.

This short animation shows how human beings managed to lug 30-ton stones over miles of prehistoric English countryside and stand them up The Stone Age engineering involved using giant wooden rollers and carving precisely interlocking tongue-and-groove joints to hold the heavy stones in place.

Solar panel manufacturing begins with silicon extracted from sand

The silicon is purified and shaped into wafers less than 0.2 millimeters thick, coated and connected through a criss-cross pattern of narrow and wider metal, followed by multiple rounds of lamination before bonding to a weatherproof panel.

About 99% of Earth's atmosphere is made of nitrogen and oxygen

At 78% and 21% respectively, the two elements are followed by argon with almost 1%. Trace amounts of other molecules, including greenhouse gases such as methane and carbon dioxide, and particulate matter such as dust and pollen, make up the remainder of the atmosphere's contents.

The composition of comets earned them the nickname 'dirty snowballs'

The icy relics of the solar system are composed of rock, gravel, dust, and frozen molecules, such as carbon dioxide, carbon monoxide, methane, ammonia, and water. Once close to the sun, these compounds sublimate into gases, creating a fuzzy cloud that earned the comets another nickname in history: hairy stars.

Before dynamite was invented, Erie Canal builders blasted rock with gunpowder

Constructed decades before the invention of dynamite, the Erie Canal’s toughest obstacles were blasted through using black powder charges.

How diamonds form in the deep earth

Deep within Earth's mantle, diamonds form from carbon-bearing fluids. The formation of these beautiful gemstones, the only direct samples we have of the mantle, helps scientists uncover how carbon functions deep inside our planet. Understanding this complex process aids in the exploration for new diamond deposits.

View a gallery of diagrams for each volcano type with glossaries

The three major types of volcanoes—cinder cone, composite, and shield—each exhibit unique, lesser-known subterranean and surface features, including lava bombs, lahars, and spatter. Other types of volcanoes include lava domes, calderas, fissure volcanoes, and Maars and tuff rings.

Distinguishing the three types of mineral deposits collected via deep-sea mining

The greatest interest is in polymetallic nodules—structures formed from metals in seawater collecting around a core of shell, bone, or rock. Cobalt-rich ferromanganese crusts cover underwater mountain ranges and form over millions of years of metal deposition. Polymetallic sulfide deposits accumulate when seawater seeps into volcanic rocks.

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.

A collection of molecular gastronomy techniques, from flavored air to turning oils into powder

Soy lecithin can be blended with flavored mixtures, such as herbs and Parmesan, to produce edible bubbles, which can be frozen into a solid foam. Maltodextrin can be combined with liquid fats in a food processor to create light, flavorful powders.

Understanding how atomic structure contributes to each element's properties

The outermost layer of electrons in an atom dictates how it will bond to other atoms. These bonds determine whether elements exist as solids, liquids, or gases in the environment and other characteristics. For example, electrons are freely shared between atoms in metallic bonds, allowing them to immediately re-emit light that strikes them, thus making most metals shiny.

How cultured meat is made

In recent years, a number of companies have debuted meatless alternatives to traditional burgers, chicken, and more. Some are made from soy, while others use molecular formulations to recreate the flavor profile and texture of meat. Now, actual meat...

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.