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.

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.

Nitinol is an example of a shape memory alloy, which can be trained to 'remember' a specific shape and, if deformed, revert to it upon being heated.

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.

The bullwhip was the first human-made object to break the sound barrier, producing a small sonic boom heard as a crack when flicked quickly.

What makes food crispy, and how science can be used to maximize this property

The fracturing texture experienced when biting into vegetable tempura, fried chicken, pastry crusts, and other foods comes from having a dehydrated, porous surface. When frying food in hot oil, trapped water vaporizes and escapes, creating tunnels and pores in the food as it dehydrates. Breading, particularly with the large, irregular shapes of panko, and leaveners can help create more air spaces.

When helicopters fly near sandy surfaces, these granular particles can strip off fragments from a blade's abrasion strip, which then quickly react with the air and ignite, producing rings of light.

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.

Airplanes generate enough lift to fly by accelerating air faster over their moving wings, which makes the pressure above the wings lower than the pressure below.

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.

Why professional tennis players are so picky about balls before serving

Just as swimmers shave their bodies before competitions to swim faster, experiments show that tighter, less fluffy balls experience less drag forces when moving through the air and thus produce faster serves at the cost of less control. Players may select a fuzzier ball in scenarios that call for safer, more cautious play.

Real-time tracking of individual hair cells has revealed that hairs don't actually get pushed out from the root—instead, hair cells are tugged upward by surrounding tissues that act like tiny motors.

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.

Watch the engineering challenges overcome in turning a 3D printer into a tattoo machine

The DIY project required reprogramming the printer to operate on a curved, 2D surface rather than making flat layers in 3D, editing replacement firmware to bypass temperature safety checks, and developing a rapid system to stop the tattoo in case of an emergency. The final product printed "LEG" on a volunteer's leg.

Research has found that when their symbiotic algae are not producing oxygen via photosynthesis, corals twirl hairlike structures to circulate water and draw oxygen into their outer tissues.

Tennis balls get their bounce from pressurized nitrogen inside vulcanized rubber, made from heating natural rubber with sulfur to create molecular links that harden the material.

One of the Widow Clicquot’s many innovations was the process of riddling

Riddling involves storing Champagne bottles at an angle and methodically turning them in order to collect any sediment in the neck of the bottle. The technique—which was kept a strict secret—cut down on both time and waste, allowing the House of Clicquot to outsell its competitors for decades until word inevitably leaked and riddling became the standard.

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.

Horsehead-shaped features seen on the sun and the clouds of Earth and Jupiter are examples of Kelvin-Helmholtz instabilities, where a faster-moving fluid rolls atop a slower-moving fluid.

Fiber lasers used for metal engravings can’t burn your skin

These devices use diodes and mirrors to create pulses of light that vaporize metal in billionths of a second, though at wavelengths that cannot react with organic material. Pulse width, power, and speed adjustments can produce white, black, and even colored patterns through controlled heat reactions.

The perfectly rolled burrito depends on the tortilla

Experts recommend warming a tortilla before wrapping it around the filling. Once warm, you should distribute the ingredients evenly on the back half of the tortilla for a uniform shape.

Spiral galaxies get their arms, in part, from cosmic traffic jams, in which faster orbiting matter slows down and bunches up before proceeding at higher speed once more.

Flexible integrated circuits can be built from carbon nanotubes and elastic materials

Stanford researchers arranged the nanotubes in fishnet-like networks that allow deformation without loss of function. The stretchable ICs have been shown to power micro-LED displays and may be used in smart clothing.

The Koch snowflake has an infinite perimeter enclosing a finite area

Counterintuitively, although it would be impossible to build a fence along the edges of the shape because it would require an infinite amount of materials, this perimeter can be contained in a larger shape with a finite perimeter and limited area. This is equivalent to enclosing an infinitely long spiral that never reaches the center within a circle.

Watch an animation of what happens inside cookies as they bake in an oven

As temperatures rise and butter melts, trapped water expands, spreading the dough, which remains held together by a network of proteins. Maillard reactions produce browning on the surface beyond 310 degrees Fahrenheit (154 degrees Celsius), while caramelization can be triggered by baking past 356 degrees Fahrenheit (180 degrees Celsius).

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.

While most cells possess DNA, red blood cells destroy their nuclei to maximize the amount of oxygen they carry and more easily alter their shape to fit through narrow blood capillaries.

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.

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.

Some synthetic diamonds are purposely made with defects for new technologies

Grown in plasma-filled chambers or reactors where pressures reach 800,000 pounds per square inch, diamonds can develop properties like electrical conductivity and magnetic field sensitivity through exposure to elemental impurities or removal of some of their carbon atoms.

Old credit cards can be made into guitar picks, phone stands and more

Experts recommend always cutting through the chip and the card number when disposing of expired credit cards, as the magnetic strip, the chip, and the card number all contain information that thieves might be interested in.

Spiders can make up to seven types of silk, with some able to withstand twice the force of ultra-high-strength steel of the same mass and length before breaking.

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.

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.

If a sheet of standard printer paper could be folded 42 times, it would have the same thickness as the distance from the Earth to the moon.

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.

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.