ENGINEERING

How Does a Black Box Survive a Plane Crash?

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By July 13, 2026 Updated: July 14, 2026

In the aftermath of a plane crash, investigators typically comb through debris for answers. Much like a jigsaw puzzle, they use their findings to piece together a clearer picture of what went wrong and, importantly, how to prevent it from happening again. Among the most useful tools during these investigations is a flight recorder, also known as a black box.

Even when the rest of the aircraft is reduced to rubble, black boxes are expertly designed to withstand immense physical force and other destructive factors. You may be wondering, if a flight recorder can survive a crash, why not make the entire plane out of that material? Unfortunately, it’s not as simple as that.

It’s not just the material it’s made of, but also multiple other security layers that ensure a flight recorder’s durability.

Built To Last

The name “black box” is actually a misnomer, as these devices are painted bright orange — like a traffic cone or safety vest – to make them easier to spot and recover from crash sites. There are actually two black boxes located in all large passenger aircraft (and certain smaller airplanes), a requirement of the Federal Aviation Administration.

One black box is the flight data recorder, which stores thousands of different important metrics, including the plane’s altitude, airspeed, and heading. The other is the cockpit voice recorder, which stores audible radio transmissions, general engine noises, and the sound of the pilots talking to one another, whether it’s about what they ate for lunch or problems with the controls.

Both of these recording devices are designed to withstand the same extreme thresholds. Black boxes can endure up to 3,400 Gs of physical impact, which is equal to being thrust into a concrete wall at 310 miles per hour. At most, Formula 1 drivers only sustain about 6.5 Gs, or 6.5 times the force of Earth’s gravity.

Black boxes are also built to survive temperatures of up to 2,000 degrees Fahrenheit, roughly equal to the temperature of flowing molten lava. Since planes often fly over the ocean, flight recorders are also designed to endure depths of up to 20,000 feet beneath the waves — roughly 7,500 feet deeper than the location of the Titanic.

To make underwater recovery easier, black boxes are outfitted with a built-in pinging device, which is activated when immersed in water. The box can transmit a clear homing signal from depths up to 14,000 feet. The underwater locator beacon (#6 in the illustration below) is kept on the outside of the box so it can transmit a clear signal.

Diagram of flight recorder components — Image 3: Illustration in photo folder
Credit: Encyclopædia Britannica, Inc.; Photo illustration How Everything Works

The ability to endure extreme force, heat, and pressure is made possible by the way that black boxes are constructed. A black box keeps its recording electronics (#5 in the illustration above) and power supply (#4) on one end — it’s not protected by much because it doesn’t need to be. The information the instruments gather is immediately saved to memory boards (#1), and thus the electronics are expendable after a crash.

It’s the data that’s needed, which is why the memory boards lie at the very core of the flight recorder. The central data storage unit is wrapped in a thin layer of aluminum and a 1-inch-thick layer of dry silica (#2), which works to absorb heat and protect the central component from melting.

This layer is itself encased within a quarter-inch of stainless steel or titanium (#3), providing much-needed protection against potential corrosion or any traumatic impacts. While it would be nice if airplanes were built entirely out of these durable metals, stainless steel is too heavy and titanium too expensive for that to be practical.

Once a black box is built, it’s put through the ringer to make sure it’s up to snuff. Tests include being launched out of an air cannon into an aluminum target, being crushed by 5,000 pounds per square inch of force for five minutes, and being subjected to 2,000-degree flames for an hour straight. It even has a 500-pound weight (with a protruding pin) dropped onto it like some unfortunate cartoon character.

Testing a flight recorder is no laughing matter, though. The information retrieved from one after a crash can potentially save many lives in the future.

Short Answer

Flight recorders, or black boxes, store flight metrics and cockpit audio and are designed to survive the extreme conditions of a plane crash, even if it’s over the ocean. They are data recording and storage electronics encased in multiple layers of various heat-resistant, anti-corrosive, and impact-resistant materials. Bright orange coloring and a homing signal help investigators locate a black box and what it protects: essential flight data that may point to how and why a plane has crashed.

HEALTH

What’s Holding Your Skeleton Together?

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By July 13, 2026 Updated: July 15, 2026

“What’s holding my bones together?” sounds like something a curious toddler would ask — and that you just don’t know how to answer. Muscles? Joints? It’s a good question!

Think about it: Every time you take a step, reach for a cup of coffee, or turn your head to look out the window, more than 200 bones are bending and pivoting and bearing weight, all without flying apart. So what, exactly, is keeping them all in place?

There isn’t one specific body part to point to (which you couldn’t do without your hand bones), but rather an intricate network of connective tissues. But two stand out in particular (and allow us to stand to begin with).

The Leading Cast

Diagram of the anatomical structure of a human knee — Credit: designua/stock.adobe.com; illustration How Everything Works

When it comes to keeping your skeleton together, ligaments and tendons are the most important of your connective tissues. Ligaments are small, fibrous bands that connect bones to other bones. They’re flexible yet tough, kind of like internal bungee cords — strong enough to keep everything stable, but with enough give to allow for movement.

Ligaments direct your joints (where one bone meets another) to move in the right ways and, hopefully, not to move in the wrong ways. Without them, your knee would buckle sideways, your ankle would roll out of its socket, and your shoulder would slip anytime you reached overhead.

There are more than 900 ligaments in the human body (compared to 206 bones), and they come in different shapes and sizes. Some look like strings, some like wide bands. Ligaments are mostly made up of woven strands of collagen and elastin proteins. Depending on the types of movements they’re likely to be needed for, some have more collagen for toughness, and others have more elastin for elasticity.

The other important players keeping your skeleton together are tendons, which connect muscle to bone. These transmit the force of a muscle contraction into actual movement, since your bones can’t move on their own. Together, ligaments and tendons form the connective framework that lets the skeleton function as more than just a pile of bones.

The Supporting Characters

An arm with biceps flexed — Image 3
Credit: Curated Lifestyle/Unsplash.com

While ligaments and tendons are doing most of the heavy lifting (sometimes quite literally), there are a few other things that help keep your skeleton moving smoothly. Bursas are fluid-filled sacs that help reduce friction in joints. The synovial membrane seals the joint (turning it into what’s known as a “joint capsule”) and secretes a thick fluid that aids in lubrication and provides nutrients to the surrounding cartilage.

Cartilage is a type of connective tissue that acts as a shock-absorbing buffer at the ends of bones, preventing them from grinding directly against one another. Grinding and friction between bones lead to wear and tear, just as they do in garden shears or bicycle chains. Rather than just holding bones together, these tissues help protect them, especially over time.

When most of us think about joints in our body, we think about the moveable ones: hinge joints (such as your elbows and fingers), pivot joints (the top of your spine), and ball-and-socket joints (shoulders and hips), for example. But some joints barely move at all. Your skull, for example, is made of different pieces, but they’re fused together so tightly that they don’t move, making up a type of stationary joint called sutures.

The next time you turn a doorknob or switch on a light without injuring yourself, remember that there’s a whole intricate system working together to get the job done. Without it, we’d all fall apart.

Short Answer

Your skeleton is held together by a variety of connective tissues. Ligaments are flexible-yet-tough bands that link bone to bone while tendons connect muscle to bone, translating muscle contractions into motion. Together with cartilage, synovial fluid, and fluid-filled bursas, these tissues form the connective system that keeps your skeleton functional and, both figuratively and literally, in shape.

SCIENCE

Why Doesn’t Stainless Steel Rust?

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By July 8, 2026 Updated: July 8, 2026

Leaving a garden tool out in the rain seems like a simple oversight until you need to use it and find how quickly ordinary steel can turn orange and flaky. Meanwhile, the stainless steel spoon in your kitchen drawer, the sink in your bathroom, and even the metal on city skyscrapers can stay shiny for years despite constant exposure to water and air.

So what gives? If both types of steel are made mostly of iron, why does one rust while the other seems immune from the phenomenon? The answer is that the iron atoms in stainless steel are protected by another metal.

This metal not only prevents rust, but does so by teaming up with the very thing that causes it in the first place.

Iron Needs Its Own Armor

Rust is a type of corrosion that occurs when iron reacts with oxygen and water. That’s why it often occurs when something metal is left outside or gets wet. The reddish-brown material that forms — technically known as iron oxide — is weak and flaky.

Worse, it doesn’t stay put. As it flakes away, it exposes fresh iron underneath, allowing the corrosion to continue in a vicious, damaging cycle. Stainless steel contains iron too. Not mass-produced until the 19th century, steel is an alloy that adds carbon to iron to make it a stronger, harder metal.

There are different types of steel alloys — which include different proportions of various metals like nickel and manganese — for different applications. Stainless steel is at least 10.5% chromium (and no more than 1.2% carbon), which is its secret weapon against rust. That small addition makes a big difference.

You can think of the included chromium as a microscopic suit of armor. When it comes into contact with oxygen in the air, it forms an extremely thin layer of chromium oxide on the surface of the metal.

Unlike rust, this layer is stable, tightly bonded, and remarkably durable. It acts as a barrier that prevents oxygen and water from reaching the iron below. The layer is microscopic — you can’t see this invisible shield with the naked eye.

The chromium oxide forms so quickly and effectively that it prevents the deeper, destructive corrosion we recognize as rust. The protective coating is only a few atoms thick, yet that’s enough. Better still, this coating can repair itself. If the surface of the metal is scratched, fresh chromium is exposed, and a new protective layer forms almost immediately as long as oxygen is present.

A self-healing suit of armor? It doesn’t get much cooler than that. That doesn’t mean stainless steel is indestructible, though.

Chromium cell on the Periodic Table — Credit: Encyclopædia Britannica, Inc.

In extremely harsh conditions — such as prolonged exposure to saltwater or certain chemicals — can eat away at the chromium layer. A lack of oxygen also prevents chromium oxide from replenishing itself. Then, the iron in the steel is unprotected from the elements that cause it to rust.

That’s why marine-grade stainless steel used on ships often contains additional elements such as molybdenum, which provide additional defense.

Still, for everyday uses, stainless steel’s self-renewing shield makes it one of the most durable materials around. It might not be nearly as valuable per pound as gold or platinum, but when it comes to keeping the sink shiny and the knives rust-free, it’s an MVP.

Short Answer

The iron in steel will rust when exposed to oxygen and water. Stainless steel resists rust because it contains chromium. When chromium reacts with oxygen, it quickly forms a thin, invisible layer that shields the iron underneath. This protective layer continually repairs itself if damaged.

SCIENCE

Why Does Helium Change Your Voice?

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By July 8, 2026 Updated: July 8, 2026

It’s a familiar (though potentially dangerous) party trick: inhaling helium from a balloon to make yourself sound like you sing backup for Alvin and the Chipmunks. But have you ever considered why helium makes a baritone voice sound like Mickey Mouse?

It’s actually the same reason it makes balloons float: Helium is less dense than air. Here’s how that affects what’s going on in your throat.

The Shape of Your Voice

Diagram of the vocal tract — Credit: Spencer Sutton/Science Source

Helium doesn’t actually change the pitch of your voice at all. Instead, it alters the timbre, or sound quality. Every voice has a unique timbre in the same way that every musical instrument has a unique sound. An F-sharp, for instance, will sound very different on guitar as opposed to a piano — they’re the same note, but the tones will be very different thanks to the physical properties of each instrument.

Similarly, the physical characteristics of an individual’s vocal tract — which is made up of a laryngeal cavity (or voice box) and the throat, mouth, and nasal cavities — creates their unique voice, whether it’s Johnny Cash or Smokey Robinson.

Your voice box contains two bands of muscle tissue covered in fleshy mucous membranes called vocal folds (or cords). When you speak, a column of air shoots through an opening, or glottis, between the folds. This sudden blast of air vibrates the vocal folds rapidly, which chops the air into discrete fluctuations, forming sound waves.

The more cycles per second (higher frequency), the higher the pitch. These sound waves travel through the throat and into the mouth and nasal passages, where they resonate and are then released – or spoken out loud.

Keeping it Light

Person speaking in front of a microphone — Credit: Getty Images/Unsplash.com

Normally, the gas in your voice box is oxygen and nitrogen, since that’s what we’re typically breathing in. Helium is a lot lighter than normal air – its atoms are literally smaller because they have fewer protons, neutrons, and electrons than oxygen. That’s why balloons filled with helium float, but balloons you fill with your own breath sink to the floor.

So what happens when you grab one of those floating balloons at a party, open it, and inhale the helium? Once you start talking, your vocal cords interact with helium atoms instead of those of normal air.

Lightweight helium atoms make the gas much less dense than normal air, so sound waves travel through it faster. The frequency is still the same, but the shape of the waves change and interact differently with your vocal cords. The higher-pitched portions of your voice become amplified. Simultaneously, lower tones are flattened. So sound traveling through a helium-filled voice box becomes squeakier.

The result? You sound like Tweety Bird. But because the helium you inhaled is flushed out of your voice box after a few breaths of normal air, the effect wears off before long.

Short Answer

Air passing through and vibrating your vocal cords creates sound and allows us to speak. Helium atoms are lighter and vibrate much faster than normal air (nitrogen and oxygen), so they resonate more strongly with the highest frequencies of your voice. This gives it a higher, squeakier sound until the helium is fully exhaled.

NATURE

Why Don’t Spiders Get Stuck in Their Webs?

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By July 8, 2026 Updated: July 8, 2026

If you’re setting up a snap trap to get rid of a mouse, you need to make sure it doesn’t accidentally catch your fingers. For the same reason, hunters need to be very careful not to step into their own bear traps. Now imagine a spider, some of which spend most of their time living inside a trap of their own design — a trap that’s also one of nature’s stickiest.

Web-building spiders (not all spiders build webs, and web structures vary widely among species that do) construct elaborate silk structures designed to ensnare fast-moving insects. Yet the architects themselves can race across the strands, hang upside down, and sit motionless in the center without getting stuck.

What’s their secret? The answer comes down to creative engineering, specialized anatomy, and some fancy footwork.

A Sticky Situation

Spiderweb — Credit: Zdeněk Macháček/Unsplash.com

The most famous examples of sticky webs are the classic, circular webs made by common garden spiders. Orb-weavers begin by laying down a structural skeleton of radial lines — the spokes of the wheel — that support the rest of the web. This framework is made from a type of silk that is incredibly strong but often completely dry and nonsticky.

To understand why a web-weaving spider doesn’t get trapped, you first have to look at how its web is built. A web is not a uniform sheet of glue, and in fact, some webs don’t use sticky silk at all. Sheet-web weavers, for example, rely on a chaotic grid of nonsticky threads to physically trip and entangle prey rather than glue it down.

Once this safe scaffolding is secure, a spider begins to spin the viscid spiral, where the silk is coated in microscopic glue droplets. Just as many of us can navigate our home in the middle of the night without turning on the lights, a spider instinctively knows its own web’s blueprint.

This allows the creature to intentionally avoid the sticky spirals as it meticulously walks along the dry radial spokes. When it does touch a gluey line, a spider uses careful leg movements to minimize further contact and delicately avoids pulling the strands toward itself.

Fancy Footwear

Spider walking on its web — Credit: RMT Photography, LLC/stock.adobe.com

Orb-weavers are also equipped with unique, branching claws at the tips of their legs, surrounded by dense, stiff bristles. These specialized hairs minimize the surface area that comes into contact with sticky silk, preventing glue droplets from fully grabbing hold — even when the spider is maneuvering close to a captured meal that’s covered in the stuff.

Researchers have discovered that these spiders’ legs are coated in a specialized, nonstick chemical layer that acts much like cooking spray on a frying pan. Even if a leg brushes against a sticky droplet, the adhesive struggles to cling on.

That doesn’t mean spiders are completely immune to their own traps. If forced into a sticky strand incorrectly, a spider can become just as entangled as its prey. Still, a spider casually strolling across its sticky web is a testament to evolution, a diverse toolkit of specialized silks, and a lifetime of taking things one step at a time.

Short Answer

Though there are different types of spiderwebs, many are made from a silk coated in microscopic glue droplets to entrap prey. Web-building spiders avoid getting stuck in their own traps by walking primarily on dry, structural strands and by utilizing specialized leg bristles and nonstick chemical coatings to repel the glue.

HEALTH

Why Can’t We Drink Salt Water?

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By July 8, 2026 Updated: July 8, 2026

Most sports drinks, such as Gatorade, are designed to hydrate us even better than plain water because they’re loaded with electrolytes. Electrolytes are what we call various minerals essential to our basic life functions, including the two that make up salt — sodium and chloride.

We lose these minerals as we perspire (which is why sweat is so salty), so electrolyte drinks help replenish them in addition to quenching your thirst. But if salt is made of purely electrolytes, why can’t we just take in a mouthful of salt water to replenish our energy? After all, it’s common knowledge that you can’t drink seawater because, rather than rehydrate you, it dehydrates you.

So what makes the salt in Gatorade healthier than the salt in the ocean? The answer is quantity, not quality.

Everything in Moderation

Underwater POV — Credit: Cristian Palmer/Unsplash.com

While it would certainly make things easier when it comes to spending time out on the ocean, drinking seawater isn’t an option for humans. A pinch of salt in our blood is a good thing, but high salt content affects kidney function and can lead to high blood pressure, strokes, and heart attacks.

Salt is composed of two elements: sodium and chloride. Among other roles, the elements are used by our nerves to communicate with one another, using it to send signals and impulses throughout our body. It’s also employed by our body to contract and relax our muscles, so we actually need it to move around.

On average, we humans require around 500 mg of sodium each day for the element to properly do its job. When we consume salt through food, it’s diluted with the intake of freshwater that we drink directly or through water-based drinks and foods. This helps our kidneys remove any excess salt from the bloodstream through urine.

When you ingest too much salt in comparison to the amount of freshwater you’ve taken in, our kidneys struggle to remove the excess salt from your bloodstream. Even if you drink a lot of seawater, being unable to flush out the salt not being used by your body actually makes you more thirsty, not less.

And if you can’t get enough freshwater to bring your salt-to-water ratio down, water from other parts of your body, such as muscle tissue, will be used in an attempt to dilute it. Borrowing this water needed elsewhere in your body is what makes you dehydrated, which can cause sickness and even be fatal in extreme cases.

A Pinch of Salt

Person adding electrolytes to their drink — Credit: George Dagerotip/Unsplash.com

But if you’re thinking: “If salt is an electrolyte, then it should help with hydration, not make it worse,” here’s the difference. The salt you ingest during or after a particularly tough workout or a few hours spent in the sun typically comes through a water-based sports drink, snacks, or a meal.

These electrolyte solutions have a far smaller proportion of salt than seawater does, and the freshwater it includes also helps flush any excess sodium chloride from your blood. Electrolytes, whether from a sports drink or a banana, also help relieve symptoms of electrolyte imbalance (including brain fog, fatigue, irritability, and more), which can be caused when you lose too much electrolytes through sweat.

That’s why it’s a good idea to pack a salty snack or your favorite Gatorade flavor alongside your largest reusable water bottle before working up a sweat at the beach. The ocean is for swimming, not drinking.

Short Answer

The sodium and chloride in salt are electrolytes, essential minerals our body needs to function, but they’re depleted when we sweat. Certain foods and drinks, such as Gatorade, can replenish our electrolyte levels but have a much lower concentration of sodium chloride (salt) compared to seawater. Our kidneys can’t process all the salt in seawater, leaving too much of it in our bloodstream, which dehydrates us and makes us sick.

TECHNOLOGY

Could We Build an Elevator to Space?

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By July 7, 2026 Updated: July 8, 2026

Is it possible for humans to get to space without blasting off on a rocket? After all, the transporter that beams people up on Star Trek doesn’t exist in real life and it’s not like we can just call an Uber to Saturn.

A space elevator may be one possible option. It’s a theorized structure that functions very similarly to the same type of elevator you ride up and down a tall building, except that you can take it from the ground all the way to Earth’s orbit. Instead of flying to the moon, you’d ascend up a very long elevator cable. This would arguably be a safer and far less expensive way to move astronauts and cargo beyond Earth’s atmosphere.

But building a space elevator would be a daunting task for a multitude of reasons — in fact, it may be impossible. However, the idea has plenty of proponents, including some who are working to make it a reality.

How Does a Space Elevator Work?

The first question to answer is one of distance, but it’s also philosophical: Where does space begin? The most common answer is the Kármán line, an invisible boundary between 50 and 62 miles above Earth that marks the point where our atmosphere ends. To work, though, an elevator would need to have its counterweight much further out.

Instead of the moon, let’s imagine we want an elevator that gets astronauts to the International Space Station (ISS). First, we’d have to move the station to geostationary orbit over the equator so that it “stays” in place — when you look up at the sky, it would always be in the same place. (Imagine taking a building’s elevator if the roof was always moving around, and you can see why the ISS needs to be geostationary.)

To remain geostationary, the ISS also needs to move much higher in the sky than it currently is. Today, it’s roughly 400 km above the surface, but the center of mass for a space elevator must be at least 35,786 km high to stay in sync with Earth’s rotation and its ground-level base. That means the cable running from the ground to the ISS would be more than 22,000 miles long. The cable would also need to run much, much further out from the ISS, with its end being the counterweight that allows elevators to function.

At this point, the ISS doesn’t need to use any boosters or rockets to move. It’s being pulled by the Earth by centripetal force. It’s not much different than quickly spinning a yo-yo like a lasso, with the yo-yo moving around your head at a fixed distance, rather than smacking you in the face. Once a taut cable connects the ground to the ISS, an elevator car can then move up and down it at will.

If something else is used as the center of mass, the ISS can even be moved back down to 400 km and just hang off the cable. Instead of orbiting the Earth, it would be pulled along. After getting on at ground level (and pressing the “Up” button), astronauts could hop off on the ISS while others go all the way up — like coworkers in a really, really tall office building.

Diagram of how a space elevator works — Credit: How Everything Works

Can We Build a Space Elevator Right Now?

One downside to a space elevator, as opposed to a rocket, is that it would take a lot longer. If the elevator car moves at the velocity of a high-speed train, a journey to the ISS would take a few hours, but would take more than a week to get to the center-of-mass that’s at geostationary orbit. However, a bigger flaw in the space elevator idea is that we physically can’t build one — at least not yet.

Not only would the cable of a space elevator need to be thousands of miles long, but it also would need to be incredibly strong. However, it also needs to be lightweight. Stainless steel is strong, but it would collapse under its own weight if it’s used for a 22,000-mile cable.

Currently, there’s no material that we can make with the strength-to-density ratio needed for a space elevator. Graphene, carbon nanotubes, and diamond nano threads are among the low-density, high-strength materials that have been proposed as potential building blocks for the space elevator, but thus far they offer more promise than proof. A design for a space elevator recently won a prize, but even the designer admits the idea is “a bit fanciful” — for now.

Other potential issues involve clearing satellites and space debris from the path of the cable (airplanes would also need to fly around it). If the ground base of a space elevator were on a mobile ocean platform, it could theoretically shift just a little bit to dodge moving debris while still staying in sync with the top. There are also threats to the cable and base station, such as hurricanes and lightning strikes. You wouldn’t want a 22,000-mile cable snapping and falling back to Earth, even if much of it would burn up in the atmosphere.

Finally, anyone riding a space elevator would need to be shielded from radiation, which increases as you leave Earth’s atmosphere. Traveling on an airplane exposes you to cosmic radiation since the atmosphere is thinner and doesn’t block as much. Two cross-country flights expose you to as much radiation as a standard X-ray. Traveling by space elevator can take you much further from Earth’s natural shield and for longer periods of time, greatly increasing exposure.

So, even if we find the materials, money, and willpower to build an elevator to space, there will be plenty of other problems for us to solve before safely using it.

Short Answer

In theory, a space elevator can be built by running a strong cable more than 22,000 miles long from Earth’s equator to a base that orbits in sync with the elevator on the ground. In practice, this is a near-impossible task, since we don’t have any material that’s strong enough but still lightweight enough to avoid collapsing under its own weight. Even if we could build such a cable, we’d need to protect it from damage and protect its riders from cosmic radiation.

HEALTH

What Happens When You Hold in a Sneeze?

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By July 7, 2026 Updated: July 8, 2026

Have you ever been standing in a crowded elevator, or maybe sitting in an important meeting, before suddenly feeling a big sneeze coming on? Maybe you’re the type of person who will just let it rip, but most of us will do our best to hold in the sneeze. It can seem like a virtuous act of self-control — just pinch your nose, close your mouth, and wait for the urge to pass.

But a sneeze is more than a potentially germ-dispensing annoyance. It’s a powerful reflex with a specific role to play, and interrupting that process can put surprising stress on your body. Here’s what happens when you try to repress the reflex.

Under Pressure

Pollen — Credit: Alex Jones/Unsplash.com

Technically called sternutation, a sneeze begins when nerves inside your nose detect something that doesn’t belong there, whether it’s dust, pollen, germs, or even black pepper.

Your body responds by compelling you to take a deep breath and by building up pressure in your lungs and respiratory system. Your chest muscles then squeeze your lungs hard, releasing a sudden blast of air through your nose and mouth. That’s meant to force the irritants out and keep you from getting sick, the same way you’d use pressurized air to clear debris from your keyboard or power tools.

You may feel a sneeze coming as the irritated nerves in your nose are triggered. You may also feel the moments before one as those nerves send a signal to your brainstem, which prepares you for a sneeze by tightly closing your throat, eyes, and mouth. This gives you a very brief window to hold in a sneeze.

When you do, all of the built-up pressure has nowhere to go — and that’s a problem. Instead of venting through your nose and mouth, the pressurized air is redirected into other parts of the body, such as the sinuses, ears, and potentially other areas too.

Friendly Fire

Credit: Fellipe Ditadi/Unsplash.com

Researchers have found that suppressing a sneeze can increase pressure inside the respiratory system to levels from 5 to 24 times higher than those generated during the sneeze itself. Your ears are particularly vulnerable to this excess pressure, especially if it’s redirected through the eustachian tubes, which connect the back of the nose to the middle ear.

In rare cases, more serious complications can even occur, including throat injuries, infection, and damaged blood vessels. Fortunately, most people who suppress a sneeze won’t experience any lasting harm.

Still, experts generally agree that the safest approach is simply to let the sneeze happen (of course, you should be considerate of those around you and sneeze into your elbow) rather than trying to stop it altogether.

After all, that explosive “achoo” is your body’s way of keeping unwanted intruders from traveling deeper into your respiratory system. Rather than trap them inside, the healthiest thing you can do is let nature take its course and blast them from your nostrils like a spaceship purging its airlock.

Short Answer

A sneeze is the body building pressure in your chest to expel irritants and germs from your nose. Holding in a sneeze traps that pressure, which increases and is redirected elsewhere, such as your ears or sinuses. Most of the time this causes no serious harm, but in rare cases it can cause injury, which is why experts recommend letting a sneeze out rather than suppressing it.

TECHNOLOGY

How Do Earthquake Alerts Arrive So Fast?

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By July 7, 2026 Updated: July 8, 2026

Depending on where you live, earthquakes may be a common experience. The United States experiences thousands of seismic events every year, the vast majority of which are on the smaller side (between 2.0 and 3.0 on the Richter scale). Though you might not feel quakes of this size or smaller, sensitive detection systems do — usually before you even notice the ground begin to shake.

The advanced equipment used by seismologists — people who study earthquakes — is a scientific feat in its own right, but the fact that these systems can also alert you to an impending quake seconds, or even tens of seconds, in advance, is a modern-day miracle.

That may not seem like a lot of time, but it’s all you need to brace yourself and remain safe from falling debris or other hazards until the shaking has stopped. So, how do early earthquake warnings reach you so quickly?

Light on Its Feet

There’s no way to actually predict an earthquake in advance, and that likely won’t change anytime soon. That’s what makes early warning systems so remarkable — and vital. The reason alerts delivered to your phone are so fast is that, like other data you receive, they’re transmitted at the speed of light (186,000 miles per second). As for the process leading up to the alert being sent out, it’s a bit more involved but no less impressive in its speed.

Early warning alert systems, which are scattered across the globe, are delivered between five and eight seconds after a quake starts. That’s how long it takes for seismic waves to reach the nearest monitoring station and for said outpost’s computer systems to analyze the data and send out an alert with the appropriate information, such as location and intensity.

Factors including the type of terrain and how deep the earthquake originates affect how fast it travels through the ground. Different types of seismic waves, which are determined by their type of motion, also travel at different rates. Fortunately for us, the most intense and violent type — surface waves — is also the slowest, giving light-speed alerts taking off from nearby stations a huge head start.

If you’re especially close to the epicenter — usually within 10 miles — you might feel the ground shaking before receiving the alert. The rest of the time, though, you should have at least a few seconds to brace yourself.

Illustration of how earthquake alerts work — Credit: How Everything Works

Every Second Counts

A few seconds might not sound like a lot, but it could be the difference between a good outcome and a bad one. That amount of time could easily provide enough time for a driver in traffic to pull over to safety or someone at home to drop, cover, and hold on. (Despite what you may have heard, you shouldn’t stand under a doorway during an earthquake.)

Any number of high-stakes situations — a surgeon performing a procedure, a chef cutting vegetables, a farmer handling heavy machinery — would benefit greatly from even the slightest bit of advance warning. There are multiple earthquake detection apps available that can warn you on your phone, though in certain parts of the country, the loud, shrill, government emergency alerts will also warn anyone with a smartphone.

The technology is continuously being refined and advanced to make earthquake alerts even the tiniest amount faster. Some systems use the accelerometers on smartphones of participating users to monitor shaking. The equipment is far less sophisticated, but if users are closer to an epicenter than official monitoring systems, an alert sent to others in the network may come sooner than an official one.

A combination of methods may turn out to be the best, because when it comes to earthquakes, any warning is better than no warning.

Short Answer

Earthquake detection systems work incredibly fast once seismic waves reach them. The alerts they send out over cellular and radio networks travel at the speed of light, faster than the seismic waves that have passed the monitoring station and are heading toward you through the ground.

HEALTH

Why Do Your Fingers Wrinkle in Water?

Credit: asrul rowi—iStock/Getty Images

By July 1, 2026 Updated: July 1, 2026

If you love spending time soaking in the tub or swimming in the pool, you probably know that it doesn’t take very long for your fingers to transform, changing from smooth and soft to wrinkly and pruned. But why doesn’t the skin on the rest of your body wrinkle the same way? And what exactly is going on?

This is something scientists have been studying for decades. Initially, many assumed that water around you passes through the upper layers of skin, through a process known as osmosis, causing cells to swell as they get waterlogged. But modern research shows the reason your fingers prune is much more complex. And it involves your nervous system.

Shrinking in the Wash

Two hands under the water — Credit: Polina/Unsplash.com

The outer layer of your skin, called the epidermis, does absorb some water — that much is true. It usually takes between a few minutes and a half hour depending on the water’s temperature. But pruning is way more involved and is controlled by your nervous system, the same network in charge of your fight-or-flight response.

Research published in the British Medical Journal in 1973 confirmed this connection, discovering that injury to the median nerve, which helps you feel and move your fingers, prevented wrinkles from forming on fingers that were submerged in water. The median nerve is part of your sympathetic nervous system, which controls automatic bodily functions such as sweating and blood pressure.

While scientists still aren’t exactly sure why, the leading theory is that the wrinkling in your fingers happens when nerves trigger blood vessels just below your skin to narrow around sweat glands. This shrinking “pulls” your outer layer of skin inward, making your fingers look like shriveled raisins. The mechanism is called vasoconstriction and it’s controlled by your median nerve.

Vasoconstriction may be the “how” when it comes to your fingers pruning, but it doesn’t explain the “why.”

Early Humans Needed to Get a Grip

Hand touching a wet rock — Credit: Eduardo Ramos/Unsplash.com

There’s evidence that finger pruning has to do with adaptation and evolution, and our fight-or-flight instinct. In fact, several studies have shown that wrinkled or pruned fingers are better at grasping and holding wet objects than smooth and dry fingers. Like textured gloves or treads on a tire, the uneven surface of pruny fingers improves grip by concentrating friction, shifting load, and better interlocking with surface irregularities.

The grooves in waterlogged fingers also channel water away, allowing for better surface contact with what your hands are grabbing. Early humans may have evolved so that our fingers (and toes) prune just enough to help us grip slippery rocks and other slick surfaces when we’re in the water.

The process is totally normal, and it doesn’t last. Once your skin dries, your blood vessels go back to normal and the wrinkles disappear. (While having better grip 24/7 may seem like a good idea, evolutionarily speaking, it would come at the expense of touch sensitivity.)

So, the next time you’re lounging in the pool and your fingers look pruned, just know your nervous system is working exactly like it should. It’s even making it easier for you to pull yourself out of the water or grab a nearby drink without spilling it.

Short Answer

Your fingers wrinkle when they’ve been in water because your nervous system tightens tiny blood vessels, pulling your skin into folds like vacuum-sealed shrink wrap. Scientists think this may have evolved to help early humans grip wet objects better (or dry objects with wet hands).