O-rings contain fluid within a system

Low temperatures led to the equipment failure that caused the Challenger disaster

The polymer chains that make up an O-ring give it the ability to quickly deform and fill in gaps to seal fluids, including the hot gases from the Challenger's rocket boosters. Cold weather on the day of launch stiffened the O-rings, reducing their flexibility and sealing properties.

A tube-and-diaphragm system tells gas pumps when to stop providing fuel

As long as air passes freely through a small hole at the end of the nozzle, the diaphragm is inflated, and fuel flows normally. Once fluid reaches the hole, the change in pressure from the difference in air and fluid densities collapses the diaphragm, which cuts the flow of gas.

Friction is the force that resists the sliding of surfaces along one another

Friction always acts to resist movement and is determined by how rough the surfaces are and how hard they are pressed together. In the case of fluids, friction arises from the relative motion between adjacent fluid layers, which act like sliding surfaces.

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.

Adhesion molecules and intercellular junctions allow cells to connect together

While some organic structures are mostly composed of non-cellular components (e.g., collagen and calcium phosphate minerals in bones), tissues and organs composed of connected cells rely on specialized proteins and connections to create watertight seals that protect cells within the interior from environmental molecules.

Manholes connect underground sewer and water drain pipes

Wherever a portion of sewer is connected to another, a manhole is built. These serve both as access points for maintenance and as connectors for the system. This video shows how crucial manholes are for proper sewer functioning.

Scientific applications of bubbles include logic gates, laser production, and medical imaging

Microbubbles of nonreactive gas can be administered to improve the reflection of sound waves and the resulting imaging during an ultrasound. Bouncing light waves within a bubble can stimulate emission of light from a trapped chemical, just as occurs within a laser, and bubbles can act as valves that control the flow and reaction rates in microfluidic systems.

O'Neill cylinders are free-space habitats that spin to create artificial gravity

Popularized in the 1970s by Princeton physicist Gerard K. O'Neill, the 15-mile-long structures would be manufactured from lunar and asteroid materials and house human colonies. His space colony ideas have since influenced works of science fiction.

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.

Ring galaxies, the rarest kind in the universe

Galaxies come in different sizes, but when it comes to shapes there are just four kinds: spiral, elliptical, irregular, and the rarest kind, ring. Ring galaxies only form in the event of a small galaxy passing through a large one, but there's more to them that that. This page explores these rare and beautiful heavenly bodies.

The collapse of gas bubbles in the joint synovial fluid causes 'cracking' knuckles

The human population can be divided into two categories: those who crack their knuckles and those who don't. Do you know the technical term for this phenomenon is "tribonucleation?" What actually happens inside a knuckle when it pops? This visual explainer breaks down finger joint popping in real time.

Mid-ocean ridges are underwater volcano systems where tectonic plates diverge

New ocean crust is formed at these ridges as magma rises from Earth’s mantle and fills the space between the spreading plates. The speed of divergence influences ridge shape, with slow spreads forming rugged valleys and fast spreading creating smooth, wide slopes.

Meet the Earth's 'radiation donuts'

Radiation donuts might summon up a certain television cartoon character's favorite snack, but they're something else entirely. Also known as Van Allen belts, these zones of radiation arise from charged particles emitted from the sun and subsequently captured by the Earth's magnetic field. Understanding the underlying physics of the Van Allen belts is critical to modern-day telecommunications.

Infants are particularly at-risk for ear infections

The Eustachian tubes, which connect the middle ear to the upper throat and help to drain fluids and equalize pressure, are relatively flat at birth, making it hard for gravity to assist with drainage. The angle of these tubes changes and becomes steeper as we age, making fluid buildup in the ear canal less common.

How the body produces its own opioids

Opioids act on the body's own opioid receptor system. The endogenous opioid system comprises four molecule receptor types found throughout the body. When activated, these receptor types trigger the release of dopamine and suppression of noradrenaline, neurotransmitters, respectively, associated with reward and alertness. This opioid system helps regulate emotions, and its disruption is linked to neuropsychiatric conditions, including depression, PTSD, and Alzheimer's disease.

Nearly all natural rubber comes from cloned trees in Southeast Asia

Synthetic rubbers have been unable to mimic the strength and tolerance to heat and pressure provided by natural rubber. This makes rubber trees essential to major global infrastructure, despite being vulnerable to disease due to a lack of genetic diversity.

Explaining how water's movement between different salt concentrations can generate electricity

Water naturally moves from regions of low salinity, such as freshwater, to regions of high salinity, such as ocean water, across a semipermeable membrane. This movement produces pressure that can be harnessed in osmotic power systems to drive turbines and generate electricity, much like in hydroelectric plants.

Series I bonds are a form of government savings bonds created to shield your investments from inflation

Specifically, I bonds earn interest from both a fixed rate and an inflation rate. This article explains who might benefit from investing in I Bonds—for instance, people seeking to invest savings they do not need to access in the near future.

Why new Rolexes can cost less than used ones

It's reasonable to assume a new Rolex watch—which often sell for thousands of dollars each—would be more expensive than a used version. However, that's increasingly not always the case. This video explains why some used Rolexes cost more than their new counterparts. Watch it here.

Many chemicals used in fracking fluid have been classified as toxic

Although the fluid has been known to leach into drinking water supplies, raising health concerns, fracking is exempt from federal clean water regulations due to a loophole in the Energy Policy Act of 2005 championed by former US Vice President Dick Cheney.

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.

Understanding R0, a measure of how contagious a pathogen is

The R0 value is a basic measure of how many people an infected person will transmit a pathogen to, on average. If R0 is less than 1, transmission dies out; if greater than 1, an outbreak is likely. Measles has one of the highest known R0 values at almost 18, meaning that after four transmission steps, more than 100,000 people could be infected.

Exercise helps make your arteries more elastic

Regular aerobic exercise releases nitric oxide, a key molecule that relaxes blood vessel walls and improves vascular function. These exercise-induced adaptations make the heart work more efficiently and blood vessels become more elastic, leading to improved circulation and lowered cardiovascular risk.

Drum shields help prevent mic bleed and dampen drum sound

Made of plexiglass or acrylic, the shields are commonly seen in churches and live venues to prevent drums from overpowering other instruments, improving the quality of the audio mix.

An oligopoly is a market structure where a few large businesses dominate the entire market

When a few large companies dominate a market, changes in pricing for goods and services affect the entire market. Airlines are a common example of an oligopoly. Because the barrier to entry in the aviation industry is high, only a few airline companies offer the majority of the industry's services. While there is some competition, pricing across the board is largely intertwined and based on other companies' prices.

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.

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

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

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

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

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.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

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.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

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

Tattoos remain visible on your skin thanks to immune cells called macrophages

Explore what it's like inside a patient isolation unit, used in situations such as treating a patient or suspected patient with Ebola.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

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.

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

A pickleball's loud 'pop' sound can reach 120 decibels, which is equivalent to a hammer hitting a nail

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.

The first robot in literature may have been a 'mechanical man' in 1907's 'Ozma of Oz,' a book in L Frank Baum's 'Wizard of Oz' series.

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states