Running a ribbon around the edge of a blade creates curls because it stretches its outer side beyond the yield—the limit at which a material can be deformed but still return to its original shape once the force is removed.

When experiencing turbulence, fluid elements undergo stretching and folding

Simulations show patches of fluid particles, such as splashes of milk, bend under turbulent flow, creating curvature that grows linearly then exponentially. This accelerated deformation enhances folding and mixing faster than other methods, such as stirring or beating.

Corkscrew roller coasters feature tracks that twist 360 degrees around their axis

Thanks to the incorporation of steel, rides have gotten increasingly versatile, daring, and smooth, performing loops and turns that are much more difficult to safely achieve with wood.

A fascinating look at why cucumber tendrils coil in opposite directions

The tendrils of cucumber plants coil when they hit a surface, creating a distinct telephone-cord look. Charles Darwin wrote about the mystery in the 1850s, though it wasn't until the 21st century that scientists figured out just how mysterious the coil is: its tendrils coil in opposite directions.

Shape memory alloys 'remember' their previous form and restore themselves if deformed

Nitinol, one such alloy, can bend back into its trained shape if exposed to heat because of a solid-to-solid phase transformation. Some showerheads already use nitinol to regulate hot water and prevent unintentional burns.

Why roller coaster loops are never circular

The beloved looped roller coaster rides used to be shapes as perfect circles and constructed with wood, resulting in wobbly machinery that gave people whiplash. After the invention of steel and further scientific understanding, Six Flags debuted The Great American Revolution—a modern, oval loop with steel that offered a safer and smoother experience.

'Viscoelasticity' allows muscles to be elongated briefly after stretching

The protective tissues around skeletal muscles consist of elastic proteins like collagen. Stretching them expands their length while retaining strength, ideal for athletes.

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

Shrink-wrap is created through a treatment of plastic with high-speed electrons

Atoms in polyethylene are bonded in long strings called polymer chains, which can be destabilized by removing hydrogen atoms via collisions with electrons. These gaps serve as bonding sites for neighboring chains to bond and undergo cross-linking, strengthening the plastic while making it more malleable.

Explore a visualization of curved spacetime under general relativity

While depictions involving bends in elastic fabrics are common to illustrate gravity, they are circular representations that rely on gravity in the real world to depict gravity in the model. The river model instead shows how bends in spacetime convert speed through time into speed through space, producing acceleration.

Turbulence is needed to make airplanes more stable and golf balls fly farther

Vortex generators—small fins placed along airplane wings—create small eddies that prevent airflow separation, maintaining lift and preventing stalls. Golf balls have dimples that create a turbulent boundary layer on their surface, minimizing drag forces.

Differences in air pressure above and below an airplane's wing allow it to fly

The bending of air around a surface causes it to flow more quickly, reducing the pressure exerted by the airflow. In a commercial airplane, the pressure difference between air diverted above the wing and air flowing undiverted below it creates enough lift to overcome gravity.

Conditioners can help unshrink garments by lubricating fibers

Textile fibers relax and shrink due to heat and moisture, disrupting hydrogen bonds. While loosely knitted fabrics are more prone to shrinkage than tightly woven ones, synthetic fibres like polyester resist shrinkage due to their crystalline structure.

For the same cost, turbines with three blades are the most resilient

Odd-numbered blade values more evenly distribute wind loads across the face of rotors, reducing bending and twisting forces on the turbine that cause wear. Modeling shows that three blades optimize efficiency and cost for everyday wind speeds.

Multi-material 3D printing produces filament waste if only one nozzle is used

When swapping between colors or materials in a fused deposition modeling system, a considerable amount of filament is purged from the nozzle before introducing a new filament. Filament extruders can create new filament from purged elements, but the device combines colors and produces filaments of inconsistent diameter.

Metal fragments can create glowing rings when sand chips them off helicopter blades

The Kopp-Etchells effect—named after two soldiers who died in action in Afghanistan—may occur when kicked-up material shaves off fragments from a helicopter blade's abrasion strip. Due to a property called pyrophoricity, the fragments react with air and ignite, producing halos.

Tiny water droplets can blur a rainbow's colors into a foggy white

When sunlight enters water droplets, it can reflect from the inside and spread out into different colors, producing a series of colorful arcs—supernumerary bows—which we refer to as rainbows. For droplets a few hundredths of a millimeter in size, these arcs overlap onto each other, producing fogbows of white light.

Tornado formation relies on wind shear to create a tube of rotating air

Once a horizontal vortex is created by air circulating between winds of different directions and speeds, an updraft, such as those seen in powerful thunderstorms, tilts the vortex vertically. The updraft then strengthens the vortex, which becomes a tornado upon touching the ground.

An exploration of what makes Olympic curling so difficult and strange

The sport is often maligned for its oddity, but this impassioned video argues it's one of the more impressive (and good-natured) sports in the Olympics. Sometimes labeled "chess on ice," curling at the Olympics uses 44-pound, 60-million-year-old granite stones all extracted from the same Scottish island.

Variations in rapidly expanding gas and mechanical elements produce fireworks sounds

Chemical compounds designed to vibrate rapidly when ignited produce whistling, screeching sounds, while crackles and pops are created by small star pellets inside the firework, which explode one after another quickly. Fluttering and chirping sounds are produced by spinning elements that rotate rapidly as the firework ascends.

Modern innovations have allowed rides to simultaneously become more extreme and safer

Several ingenious additions to roller coasters, such as extra wheels, magnetic brakes, and hydraulic system safety bars, have largely reduced discomfort and threats such as broken rides or ejected passengers.

Spikes of light around stars are artifacts of light bending around the mirror supports

Through diffraction, electromagnetic waves can bend around obstacles, as observed in the silver linings at the edges of clouds, where light should be blocked. Within reflecting telescopes, starlight diffracts around struts—beams holding a secondary mirror in place—and spreads perpendicular to them, creating pairs of spikes.

An inverted yield curve has preceded every recession that’s occurred in the last 50 years

Prolonged yield curve inversions can predict recessions, but even brief inversions can cause investors to react with knee-jerk reactions.

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.

Some earthquakes can produce smaller tremors called boomerang earthquakes, which travel in the opposite direction and ripple back to the original earthquake's source.

Winter Olympic sports highlight various laws and principles of physics

Figure skaters leverage the conservation of angular momentum during spins by tightening their bodies, and the skintight suits used in ski jumping help reduce drag. Centripetal force allows speedskaters to make tight turns, while friction on skis helps ski mountaineers climb slopes. No action can violate the conservation of energy.

Microtears in muscles from exercise cause fibers to grow back larger

Placing muscle under increased load or stress causes damage that requires rest to repair, leading to stronger, more enduring muscle over time. Muscles adapt to such increasing demands by improving their efficiency with approaches that include increasing the number of mitochondria housed in hundreds of thousands of muscle cells.

Fiberglass and epoxy resin on blades complicate the recycling of wind turbines

Between 85 and 95% of a turbine's materials—except for the blades—can be recycled. Blades have been left in landfills when not repurposed into playgrounds and sheds, but new processes may allow them to be made into pellets for injection plastics and concrete.

Paying a fee to delay paying back a loan in full is called 'rolling over' the loan

Borrowers sometimes roll over loans when they aren't able to pay back the full principal balance and accrued interest. A rollover extends the amount of time the borrower has to repay the loan, but does not decrease the amount of money the borrower has to pay back.

View the transition from laminar to turbulent flow

Using a dye released in the water, streamlines, which are parallel to one another and consistent at low flow velocities, become visible. As the water moves more quickly, viscosity cannot suppress the velocity change, and streamlines become chaotic, creating turbulence.

Laser skin treatments can promote the production of collagen

Skin resurfacing vaporizes the top layer of skin to reveal healthier, new skin, while collagen can give the skin structure and elasticity. Such procedures treat scars and burns, but may leave light spots on the skin.

Watch over a dozen fireworks effects

Adding pellets of salt to gunpowder within a fireworks shell causes them to explode with different colors, but the type of gunpowder used also has an effect. Finely ground gunpowder burns quickly, producing streaks that swiftly burn out.

Chemistry-informed advice for cooking pasta, including how to prevent clumping noodles

On a molecular level, pasta dough consists of protein structures that hold starch molecules, and the starches absorb water during cooking, forming a gel that softens the pasta. Pasta should not be rinsed after cooking. Instead, some of the pasta water should be added to the pasta sauce, as the gelatinous starch will help the sauce stick to the pasta.

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.

Hurricanes spin due to differences in air and ground speed as they move across Earth

The movement of an object across latitudes causes it to take a curved trajectory because its speed no longer matches that of the ground beneath it. This phenomenon, called the Coriolis effect, explains why hurricanes spin counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

Breaking down 'clinch covers,' a defining characteristic of '80s romance novels

As romance novels became more popular in the 1980s, publishers leaned into the books' steamier content by advertising it on their covers. Eventually, one specific kind of portrait emerged: the clinch cover, which featured a muscly man, usually shirtless, holding a woman against his chest. This episode from 99% Invisible explores the history of the trend and why it's largely disappeared from modern romance novels.

Cyclotrons move particles in spiral paths of increasing radius

After particles are injected into the center of the device, an alternating electric field and a constant magnetic field energize the particles as they spiral outward toward a target. Cyclotrons are common in hospitals that perform molecular imaging, which relies on radioactive components that decay within hours.

A barbell investment strategy focuses on balancing high-risk and low-risk investments

Barbell investment strategies emphasize bypassing medium-risk investments in favor of combinations of high-risk and low-risk investments. The idea is that the stability on the low-risk side offsets the volatility on the high-risk side, and would look like a barbell with two large weights on either end of the bar.

Random lasers can be created from biomaterials, such as peanuts and birch leaves

Rather than creating a narrow beam of light via amplification in an optical cavity, the random laser produces a red glow by scattering photons created in the natural pores of a peanut kernel after it has been injected with a solution of light-generating carbon dots derived from birch leaves.

Explore the effects of tornadoes of different scales

In this simulation, users can adjust the tornado's diameter and rotation speed to see its impact as it passes through a series of trees and a one-story home.

Sound can shatter glass if its frequency matches the material's natural vibrations

The sound made by an object when struck is its resonant frequency, which is the sound made when energy is dissipated. Providing energy at that frequency amplifies the vibrations, rather than allowing them to dissipate, which can deteriorate the object's structural integrity.

An explanation distinguishing the butterfly effect from causality, necessity, and sufficiency

In pop culture, the analogy has conveyed the impression that the flapping of a butterfly's wings has a cascading effect that directly produces a tornado somewhere else on Earth. However, butterfly-wing flapping alone is insufficient to cause tornadoes, as the complexity of atmospheric systems requires many more conditions to produce them, any of which can be the tipping point to initiate tornadogenesis.

Eating competitions can ruin a stomach's elasticity

Competitive eaters make room for all that food by toying with the stomach's ability to expand and contract. Still, doctors warn that repeated stress can destroy that ability, leading to further issues.

Some tectonic plates move faster than their underlying convection currents

Like a chain slipping off a ledge, as tectonic plates sink, their weight can pull the rest of the trailing plate forward, accelerating their movement. Plates can also break apart and fall, creating a suction effect that drives movement, resembling leaves following a passing car.

One of the leading theories behind muscle movement

According to the Sliding Filament Theory, skeletal muscle contraction is made possible by sarcomeres, which are made of bundles of myosin and actin proteins inside muscle cells. Myosin pulls itself along actin to contract a muscle, shortening the muscle and its cells and enabling physical movement. It then releases its grasp on actin so it can start the process over again if so commanded.

Bond yields are the returns investors earn from a bond's interest—and they're a key economic barometer.

Learn why magnets, like statically charged balloons, can deflect water

While the oxygen atom in water molecules strongly attracts hydrogen's electrons—producing an uneven charge distribution that pulls water toward balloons that have been rubbed against surfaces—the presence of a magnetic field alters the path of these electrons, which produce their own tiny magnetic fields. The interaction of these fields repels water away from magnets, making it diamagnetic.

Various types of tornadoes are distinguished by their shape, size, and location

Waterspouts form over water as long, thin columns of mist and air, while elephant trunks are tornadoes that elongate vertically as they become tilted during their formation, resembling the mammal's appendage. Wedge tornadoes are among the most powerful, often spanning a mile or more in width.

How jet streams, which reside in the troposphere, shape and confine pockets of atmospheric air

These fast-flowing ribbons of air are hundreds of kilometers wide and typically travel from west to east due to Earth's rotation, with the polar front and subtropical jets serving as major drivers of global circulation. Warmer air near the equator pushes the polar front jets toward the poles, which can buckle and deform them as they contain frigid polar vortex systems.

Why so many people love roller coasters even though they’re scary

When a threat arises, it triggers our bodies to go into fight-or-flight mode and prepare for danger. However, when no obvious threat to our safety is present, this natural high can become enjoyable. Some people are more likely to enjoy these thrills based on factors like individual brain chemistry or physical health.

The construction of LIGO needed to compensate for Earth's curvature

Across the 4-kilometer (2.5-mile) arms, the height of Earth's surface falls by almost a meter, preventing the lasers traveling within the arms from meeting the mirror at the end of each. Concrete slabs built beneath the arms help keep them level and provide structural support against seismic vibrations.