HEALTH

Why Is Morning Breath Worse Than Your Regular Breath?

Credit: Stephanie Berbec/Unsplash.com

By October 2, 2026 Updated: October 2, 2026

Waking up with stinky morning breath isn’t uncommon — and it has nothing to do with your dental hygiene, either. While certain foods or not brushing and flossing can lead to bad breath, morning breath is completely natural. In fact, it’s directly connected to your mouth’s natural cleaning system. Here’s how.

When Saliva Clocks Out

Close-up of a mouth — Credit: Edu Bastidas/Unsplash.com

Saliva is one of the most important features of the body’s digestive system because it actually breaks food down before you swallow, thanks to its natural enzymes and proteins. But, that’s not its only purpose. In addition to supporting digestion, saliva is the mouth’s natural cleaning system.

It’s easy to see how your saliva acts as an internal rinse cycle for your mouth. Your body is constantly secreting it (i.e. your mouth is watering) and you’re often swallowing, even if you don’t realize it, to cycle it out. As saliva makes this round trip, it washes away food particles, removes harmful acids, and kills germs.

But, like many bodily functions, saliva production slows down as we sleep. After all, it’s not like you’ll be eating anything while you’re catching your Z’s. This slowdown is what leads to morning breath. Much like a wet/dry vac that hasn’t had its water replaced, the lack of saliva can cause a stale stench in your mouth.

With less saliva, the mouth becomes drier than usual, creating an environment ripe for anaerobic bacteria to grow. The bacteria don’t need much oxygen to thrive in your closed mouth, either, and saliva’s antibacterial properties aren’t available to help curb their growth.

As you sleep, these bacteria break down proteins in your mouth. When the cat’s away, the mice will play — and in this case, your saliva is the cat. Sulfur compounds are produced as a byproduct of the bacteria going to town on your mouth’s proteins.

It’s those compounds that result in a foul odor. So even if your breath is normally fine during the day, you’ll wake up needing some mouthwash. This is also why you might still notice a bout of morning breath after taking a short afternoon nap.

Mouth breathing can accelerate overnight dryness, making an even stronger environment for these bacteria to survive. Snoring can also contribute, since it increases saliva evaporation and is often accompanied by mouth breathing. But, even if you use mouth tape and address your snoring, there’s no way to fully escape morning breath, since it’s a side effect of saliva production ramping down for the night, alongside the rest of your body.

Applying toothpaste to toothbrush — Credit: Toa Heftiba/Unsplash.com

If you don’t floss before bedtime, you might have some food particles wedged between your teeth. This trapped food decays overnight, like scraps rotting in your garbage disposal, which can also contribute to bad breath in the morning.

If you have postnasal drip while you sleep, mucus can pool in the throat and feed the odor-causing bacteria. Stomach acid might also play a role, especially for people with acid reflux or GERD, since it allows for acid to flow up into the esophagus and throat while you’re lying flat.

Once you wake up, you can quickly get rid of morning breath the same way you prevent bad breath during the day: with good oral hygiene. You can also follow up with a sip of water to rehydrate your mouth and encourage saliva production again.

And, while morning breath is natural and largely unavoidable, you can help reduce it by performing a few steps shortly before you go to sleep, as well. Brush your teeth thoroughly for two minutes. Floss to remove any food particles and plaque buildup. Follow up with a tongue scraper to remove bacteria buildup on the tongue. If you can, rinse your mouth with an alcohol-free, antibacterial mouthwash, which can also kill residual germs.

The less odor-causing bacteria you leave in your mouth before your saliva clocks out for the evening, the less they can multiply.

Short Answer

Even if you have excellent dental hygiene and your breath is fine during the day, morning breath is hard to avoid since it’s the direct result of saliva production slowing down when we sleep. The lack of saliva and resulting dry environment in your mouth creates a breeding ground for odor-causing bacteria to thrive, breaking down proteins and producing sulfur compounds that smell and taste unpleasant.

SCIENCE

Why Do Wheels Sometimes Look Like They’re Spinning Backwards?

Credit: Nate Johnston/Unsplash.com

By October 2, 2026 Updated: October 2, 2026

You’ve heard of the five basic senses: sight, hearing, smell, taste, and touch. But the way we perceive the world around us is more complicated than that. Every day your brain is constantly interpreting the physical inputs these senses take in. It uses that information to form a “controlled hallucination” that, in a sense, constitutes the reality we live in.

But despite the immense sophistication of the brain and its ability to dictate what is real, sometimes that hallucination breaks down. How your brain may interpret a given sense can be incorrect, feeding you misinformation. When the sense is sight, these mental miscalculations are known as optical illusions. And one of the most common of these sensory snafus often occurs when you’re driving down the highway.

Known as the “wagon-wheel effect,” the illusion makes the wheels on the vehicles speeding by appear as if they’re spinning backwards, even as the cars are clearly moving forward. Sometimes, they may just appear to rotate more slowly, or perhaps oddest of all, look as if they’re not spinning at all.

If you’re wondering how such an obviously contradictory illusion can occur, even when you stare at it and try to “correct” it, here’s a look at why your brain is getting turned around.

The Wagon-Wheel Effect in Motion

Camera shutter — Credit: Wan San Yip/Unsplash.com

To understand why wheels sometimes appear to spin backwards, on the highway or otherwise, it’s helpful to first explore a phenomenon first noticed in films, called the wagon-wheel effect.

It may be easier to understand the phenomenon with a bicycle wheel — go ahead and picture one slowly accelerating. At first, the spokes of the wheel are easily distinguishable as the bicycle moves forward, but the faster it goes, things begin to blur until, suddenly, it appears as if the wheel is now moving backwards.

The wagon-wheel effect is a reference to early Western films where audiences would encounter this visual phenomenon during speedy horse-and-buggy chases. And coincidentally, it’s movies — and the methods with which they’re made — that can help us understand what’s happening in the human mind.

Cameras don’t record a steady stream of visual information but instead record and display motion as individual still frames, sort of like an extended flip-book. Historically, cameras film 24 frames per second, meaning the camera’s shutter opens and closes 24 times a second, creating 24 images that together make up one second of video.

The number isn’t totally random — around this rate, the human eye can’t detect these breaks in motion and interprets the “flip-book” as continuous movement. However, spinning objects such as spokes, fan blades, or engine propellers mess with this perception of motion.

If you had a wheel with 24 spokes that was moving at the same speed as the camera, it would appear not to be moving at all. That’s because every time the camera is taking an individual “picture” of the wheel (24 times per second) a new spoke has moved 1/24th of the wheel’s circumference and into the exact same position as the previous one. When you combine the still images one after another, the 24 rotating wheel spokes appear as a single, unmoving one.

If you’re not a fan of Westerns, you may also see the effect when helicopter blades are spinning in sync with the camera, seemingly floating midair with the engine turned off. That’s when the speed of the camera and the wheel line up at just the right time and rate of motion, though.

When film is moving through the camera a little slower than a wheel, the spokes won’t line up perfectly in the same spot every frame. Instead, the next spoke may be almost to where the last one was. When you see the two images side by side, it looks like the same spoke just moved a bit backwards.

String a bunch of these frames together as a wheel is quickly spinning and your brain sees the spokes going in the wrong direction, as if the wheel is spinning in reverse — even as the wagon train, bicycle, or car is moving forward.

Eyes on the Road

The wagon-wheel effect is part of a larger family of visual illusions known as the “stroboscopic effect,” referring to how strobe lights force the human eye to take in visual information through intermittent “still” images. But even in direct lighting, the naked eye can sometimes perceive the wagon-wheel effect.

A simple way to understand how the human eye works is to compare it to a movie camera, though eyes are much more complicated. Your eyes don’t perceive motion quite the same way as a camera, but your brain processes information in discrete packets at a specific frequency — somewhat similar to the individual frames a film strip strings together.

Because of this, you don’t need a camera to see the wagon-wheel effect; it can occur even with the naked eye, as fast-moving, ambiguous information can confuse the visual cortex. Temporal aliasing is rarer with human eyesight, though, since eyes are continually taking in light. Spokes of a wheel tend to look blurry instead of appearing frozen in time or moving in reverse. However, under certain conditions, even the human eye can be fooled, including when seeing fast-moving wheels on the highway.

This can be dangerous in certain situations, such as when using lathes or saws. If the sharp teeth of a saw blade are spinning in just the right way, the blade may appear not to be moving at all — just as wheel spokes might. The effect can even be exacerbated by fluorescent lighting, which is rapidly pulsating on and off, not unlike a camera shutter.

The last thing you want to do is grab a spinning saw that looks as if it’s not even powered on. Luckily, most workshops use lighting that works around this momentary lapse in our brain’s “controlled hallucination” of reality.

Short Answer

Seen most commonly in movies, the “wagon-wheel effect” describes how fast-moving wheels, propellers, or blades appear to freeze or travel in reverse due to a mismatch between the speed of the object and the speed of the camera. Typically filming around 24 frames per second, cameras can’t accurately capture circular movement because the rate that spokes move between frames makes it seem as if they’re in the same location or even slightly behind where they were in the previous frame. When these frames are stitched together, the movement appears frozen or even going in reverse. Like a film camera, human vision also processes motion as discrete images, so the wagon-wheel effect can be observed by the naked eye, including on the highway.

HEALTH

Why Do You See Eye Floaters?

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By October 1, 2026 Updated: October 1, 2026

If you’ve ever looked up at the sky or stared at a blank wall, you might have noticed small particles floating across your eye. Appropriately enough, these are called eye floaters. (Though technically, they’re known as vitreous opacities.)

Despite appearing like solid fibers or flecks of dust, they aren’t physically floating across your pupil (that would hurt). They are actually shadows drifting across the retina, kind of like a cloud casting a shadow on the ground. But what are they shadows of, exactly?

A Look Behind the Lens

Diagram of eye anatomy — Credit: Encyclopædia Britannica, Inc.

When you look in a mirror, you only see parts of your eye, such as the pupil, iris, and cornea. But there’s a lot more going on behind the lid. The eyes contain a clear, gel-like substance called vitreous humor, which fills around 80% of the eye’s volume in the back of the eye, between the retina and the lens. Though mostly water, this substance consists of collagen fibers, hyaluronic acid, proteins, salts, and electrolytes.

The vitreous humor also acts as a filler, supporting overall eye shape and keeping the retina in place. When you’re young, it’s relatively firm and tightly pressed against the retina, but as you age, the gel becomes more watery. Like the elastic in your favorite sweatpants or a rubber band that’s been reused too many times, it becomes looser.

As this happens, the collagen fibers in your vitreous humor begin to clump together. All of this happens behind the eye’s lens, which is what focuses light for a sharper image, just like the lenses in eyeglasses. The light itself goes to the retina, which sends signals to your brain, telling it what you’re looking at.

Since the floating collagen fibers are between your lens and retina, they block light, casting fleeting shadows across the retina. Because floaters originate in your actual eye, it’s impossible to focus on them directly. When you try to, the vitreous humor also moves with your eye, shifting the suspended collagen clumps alongside your line of sight. This keeps them mostly in your peripheral vision.

Gravity also has some pull on these fibers and gives them a little bit of movement, even when your eye is completely still. This creates an illusion of active evasion, as if they’re shy and trying to avoid your attention.

Illustration showing how eye floaters work — Credit: KAMAKSI/stock.adobe.com; Illustration How Everything Works

For the most part, eye floaters are nothing to be concerned about — they’re a natural part of aging. However, in some cases, they can serve as a warning sign for some more serious conditions, especially if you notice a sudden increase in floaters or if they’re accompanied by flashes of light.

If you experience these additional symptoms, it’s worth booking an appointment with your eye doctor to get a better idea of what is happening back there and rule out concerns such as detached retinas, bleeding, inflammation, or tumors.

While floaters can be a bit distracting or annoying (especially when they tend to linger), the brain eventually learns to tune them out and they become less noticeable. If only you could do that with anything you don’t want to be looking at.

Short Answer

As you age, a gel-like fluid in your eye called the vitreous humor breaks down, causing collagen fibers to clump together. You can’t see these clumps directly, but they create shadows that seemingly “float” over your retina. They’re typically a harmless side effect of aging eyes, though they can occasionally indicate more serious concerns, especially when accompanied by flashes of light.

ENGINEERING

How Do Boomerangs Always Come Back?

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By September 23, 2026 Updated: September 24, 2026

Throw a baseball or your dog’s favorite fetch toy, and it lands wherever your arm sends it. Give it your all with a boomerang, though, and watch it sail right back into your hand, as if it changed its mind mid-flight.

Unlike its path, a boomerang’s mechanics are fairly straightforward. In fact, its design provides the same aerodynamics that keep an airplane aloft.

Return Flight

Several wooden boomerangs — Credit: Elena Pochesneva/stock.adobe.com

The first boomerangs didn’t boomerang back at all. Called kylies, early boomerangs were heavy, straight-flying hunting weapons built to strike prey with force. The returning version we recognize today was likely an accidental offshoot, refined over time by Australian Aboriginal peoples who found that lighter, curved variants were useful for sport, recreation, and mimicking predatory hawks to flush birds into nets.

The shape of a kylie originally intended to fly in only one direction was likely off in such a way that — to the surprise of the thrower — that the item came back. Take a close look at the arms of a modern boomerang. You’ll notice they’re shaped a lot like airplane wings: flat on one side, curved on the other. That’s not a design flourish — it’s an airfoil, and the reason a boomerang flies instead of tumbling to the ground like a poorly folded paper airplane.

As a boomerang spins through the air, its curved shape forces air to move faster over the top of each arm than underneath it. Faster-moving air means lower pressure pressing down, so the arm gets pushed upward. It’s the same basic principle that keeps a 747 aloft. That upward push is lift, and a well-thrown boomerang generates it on both arms as it spins.

Diagram explaining how boomerang works — Credit: How Everything Works

Here’s where it gets interesting: Because the boomerang is spinning rapidly while also flying forward, lift isn’t distributed evenly. One arm is swinging in the same direction as the throw, so it’s moving fast, while the other arm is swinging against the throw, so it’s moving slower. The faster arm generates more lift than the slower one.

You might expect that imbalance to tip the boomerang over. Instead, a phenomenon called gyroscopic precession redirects it into a turn, where a force applied in one direction ends up shifting the object’s motion 90 degrees away. (Just like a spinning top.) The result is a flight path that curves instead of running straight. Rather than changing direction mid-flight, the boomerang is really coming back toward you the entire time — assuming you throw it correctly, that is.

A few factors need to line up for a successful boomerang throw. First, you have to throw it vertically, not flat like a Frisbee, so the loop it traces curves back toward you. It also needs enough spin to stay stable. Without significant force, it’ll fly off in a lopsided arc instead of a clean circle.

If that were to happen, a boomerang’s path would be even more surprising — at least it would be to the unsuspecting person in the park you’ve just accidentally clobbered with it.

Short Answer

A boomerang comes back because it’s spinning fast while also flying forward. That spin creates uneven lift between its two wing-shaped arms, with one always moving faster through the air than the other. Instead of tipping the boomerang over, that imbalance triggers gyroscopic precession, which slowly rotates the whole spin axis and bends the flight path into a curve. Thrown at the right angle and spin speed, that curve loops all the way back around to where it started.

CULTURE

Why Does Beer Get ‘Skunked’?

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By September 23, 2026 Updated: September 23, 2026

Beer lovers agree: Nothing tastes more refreshing than a cold brew on a sweltering day. That’s not the case for beer left sitting out in the summer sun, though — one stale sip and you may decide it’s “skunked.” While it’s true that heat isn’t beer’s friend, and can leave it tasting flat and cardboard-like, that’s not the same as skunking.

The real skunking culprit is something else that coincides with a sunny day. “Skunked” isn’t solely a colorful insult for bad beer either; the term is surprisingly literal.

Don’t Let There Be Light

Two pints of beer and a coaster — Credit: Maria Klichik/Unsplash.com

First, let’s clear up a common misconception: Not only is skunking unrelated to heat, but it’s also not due to temperature swings. Letting a straight-from-the-fridge beer warm up, then chilling it back down doesn’t skunk it up.

Heat is mistakenly associated with skunking because it can affect the taste of beer by accelerating oxidation. When oxygen reacts with compounds in beer, it creates a chemical called trans-2-nonenal, which turns beer flat and makes it taste like wet cardboard. But skunking is a different reaction entirely, as it leaves a different taste and has a different origin — it’s triggered by light. (Perhaps you’ve heard skunking called by its technical term, “lightstruck.”)

Here’s how skunking works. Hops, the small green flowers used to brew beer, are used to add bitterness to the overall flavor to help balance out natural sugars. This bitterness comes from compounds in the hops called isohumulones. When those compounds are hit with ultraviolet (UV) light, they break apart. This light can come from the sun (since you’re likely not rubbing SPF 50 on your beer bottle), as well as the fluorescent lights used in the stores that sell the beverage.

The fragments of broken-down isohumulones then react with trace amounts of sulfur, which are also naturally present in beer. Together, they form a new molecule called MBT (3-methyl-2-butene-1-thiol). MBT, which can form in mere minutes in intense sunlight, is what your nose recognizes as “skunk.”

Three glass beer bottles — Credit: felix jiricka/Unsplash.com

Humans are extraordinarily sensitive to MBT. Our sense of smell can detect it at parts-per-trillion concentrations — roughly the equivalent of detecting just one millimeter diluted in an Olympic-sized swimming pool.

The term “skunked” isn’t a coincidence, either. MBT is chemically similar to the compound in skunk spray. Our sensitivity to the chemical is why you can often smell a skunk from down the street and why getting blasted with a full dose can be so traumatizing. So, when someone says a beer smells “skunked,” they’re not exaggerating.

Because sulfur is also related to certain toxins and spoiled food, humans have evolved to find it distasteful .That said, skunked beer may leave a bad taste in your mouth, but it can’t make you sick, as MBT isn’t harmful to your body.

Beer brewers and manufacturers are very aware of how skunking occurs. This is why you don’t often find beer in clear glass bottles, which provide no light protection. The industry standard is brown or amber glass, which blocks up to 99% of the UV light that triggers the skunking reaction. Green glass, associated with some famously “skunky” imported beers, only blocks about 20%. The most foolproof packaging? Aluminum cans, which block light entirely.

Next time you crack open a cold brew, remember that the packaging isn’t solely an aesthetic choice — it’s protecting the beer from a chemical reaction that gives “skunked” its apt name.

Short Answer

Beer gets “skunked” when UV light triggers a chemical reaction between two ingredients in beer: hops and sulfur. A molecule called MBT forms that provides the foul taste and smell — it’s chemically similar to actual skunk spray and humans are very sensitive to perceiving it. This is why brewers use UV-blocking brown glass or aluminum cans to prevent light from creating MBT.

HEALTH

Why Do You Jump When You’re Startled?

Credit: Curated Lifestyle/Unsplash.com

By September 23, 2026 Updated: September 23, 2026

A book crashes to the floor, a balloon pops, or someone speaks when you thought you were all alone. Before you even know what’s happened, your eyes squeeze, your shoulders shoot upward, and your entire body jerks. Your hands may fly up, and anything you were holding may make a break for freedom.

Even when you know the toaster is about to pop, your body can behave as though the bread is coming out of a cannon. What produces that sudden full-body punctuation mark?

A Reflex From Head to Toe

Startled person with eyes shut — Credit: Curated Lifestyle/Unsplash.com

The culprit is the startle reflex, a rapid series of involuntary muscle contractions triggered by an abrupt, intense sensation. Loud noises are particularly effective (especially more than 110 decibels — about the roar of a chainsaw 3 feet away), but an unexpected touch or sudden movement can also set it off.

In humans, the response begins around the eyes and spreads downward. You blink, muscles in your face and neck contract, your shoulders rise, and muscles in your trunk and limbs flex. When enough of those muscles contract almost simultaneously, you don’t merely blink or flinch: You appear to jump, as if you’re a marionette and someone just yanked your string.

The eye blink is the reflex’s fastest and most reliable component. Those muscles can react within 35 milliseconds of a startling sound, followed shortly afterward by muscles in the neck. The sequence happens far too quickly for you to consciously decide what to do — which means you didn’t mean to shoot out of your chair like it was spring-loaded.

Illustration of lower brainstem — Credit: Dr Faiz/stock.adobe.com; Illustration How Everything Works

That speed is possible because the basic response is coordinated primarily in the lower brainstem. It’s not just physically closer to your spine and the rest of your body, giving signals less distance to travel, but — unlike the higher parts of the brain that interpret the situation — it doesn’t rely on more complicated, time-consuming neurological mechanisms.

This relatively short route lets your muscles react more quickly and without stalling or second-guessing as the rest of your brain works out whether the crash came from an intruder or just a pan sliding off the dish rack. Basically, the more primal parts of your instincts have you shooting up from your seat first, and asking questions (milliseconds) later.

Scientists have proposed that this pattern may have evolved to protect against predators or attacks by quickly shielding vulnerable areas, minimizing injury, and preparing the body for fight or flight. Scrunching your face and tightly closing your eyes, for instance, may help protect your eyes, which are not only easy to injure but are also needed to help defend yourself against whatever comes next. But the true evolutionary purpose of the human startle reflex remains more of a theory than a settled fact.

Fortunately, a healthy nervous system generally learns to turn down the volume after the first jump. If the same harmless noise occurs repeatedly, the reflex usually weakens through a process called habituation. That’s why the first bang may send you airborne, while the fifth earns only an irritated glance.

Short Answer

Sudden sounds, movements, or sensations activate an extremely fast, involuntary reflex that makes muscles in your face, neck, trunk, and limbs contract in a sequence so rapid that it seems instantaneous — and makes you appear to jump. The part of your brain controlling these movements acts more quickly than the part that interprets the situation for you to respond consciously. Scientists theorize that the instinctive movement evolved to help protect vulnerable body parts and prepare you to deal with possible danger.

NATURE

Can Pets See What’s on Your TV?

Credit: Louis-Paul Photo/stock.adobe.com

By September 23, 2026 Updated: September 23, 2026

When your dog growls at a television character or your cat locks onto a video of a darting bird, what exactly is happening? Pets can see images on screens, but what they experience varies from pet to pet, and even depends on the type of TV they’re watching.

Then there’s another question: If an animal can discern what’s happening in a movie, show, or other video, does it believe that action is really occurring right there in the room?

Since we (unfortunately) can’t just ask our pets what’s going on in their heads, researchers can only infer the truth from various experiments and studies. Here’s what experts think is actually happening when Fido or Princess joins you on the couch for reruns.

Through a Dog’s Eyes

Dog watching multiple TVs — Credit: Vadim Babenko/Unsplash.com

Like a film projector, television creates the illusion of continuous action by presenting images in rapid succession. Once those images change quickly enough, the action appears smooth. Most media has a frame rate between 24 and 60 frames per second (fps), which is the number of still images whizzing by each second.

TVs and computer monitors also have a refresh rate, which is distinct from a frame rate. Measured in hertz (Hz), or cycles per second, a refresh rate is how many times per second the entire display is updated (or “refreshed”). Something at 120 Hz is refreshing the pixels on the screen 120 times per second — even if you pause a movie on one individual frame.

For humans, smooth motion is usually perceived at around 55 hertz. At slower rates, humans see flickering in the image. You might sometimes notice a flickering TV in the background of a movie or show you’re watching — that’s because the appliance’s frame rate is often not in sync with the speed of the camera filming the scene.

That distracting flicker may be very similar to what dogs see on the living room TV all the time. Dogs can detect flickering at higher rates — experiments with beagles have placed the threshold at around 75 hertz, out of sync with many older televisions engineered for human eyes.

Modern flat-screen televisions form images differently than the old boxy CRT “tube” TVs you likely grew up with. In addition to having ultra-high resolution that allows you to see individual skin pores on an actor’s face, these newer displays may also be a big improvement for channel-surfing pups. That’s because many include innovations such as continuous backlight and motion smoothing technology, as well as higher refresh rates that together may produce steadier pictures for dogs.

In one eye-tracking experiment, dogs followed a Frisbee moving across a 60-Hz screen (the refresh rate of most modern TVs). After watching it travel between two people several times, they began looking toward the catcher even before it arrived, suggesting the dogs had a very clear understanding of what they were looking at.

Even then, dogs don’t see the same Technicolor production we do. Their vision is less sharp, and while not fully colorblind, they see less distinction between colors than we do. Humans typically possess three types of color receptors (called cones), but dogs only have two, so they primarily distinguish blues and yellows and lack the ability to see red.

That means motion, sound, brightness, and contrast probably matter more than vibrant hues and sophisticated color correction. (Needless to say, the dog Oscars would have entirely different categories.)

Illustration of how humans and dogs see TV image differently — Credit: How Everything Works

Dogs can nevertheless glean surprisingly specific information from screens. In one study of 32 pets, the pups were shown either a video of a dog paired with barking or a mismatched audiovisual pairing, such as a frog croaking over video of a dog. When an on-screen dog barked, the pets acted as if nothing was unusual, but they appeared surprised by mismatched sights and sounds, indicating that they recognized the on-screen canines as fellow dogs.

Another experiment found that dogs appeared surprised when a real ball rolled across the picture of a hole rather than falling into it, suggesting that shading and perspective can create an impression of depth for them, too.

Neither result means dogs mistake television for reality. Research suggests they don’t automatically treat two-dimensional images and three-dimensional objects as interchangeable. And since Smell-O-Vision never caught on, TVs don’t provide the many layers of scents dogs often use to perceive their environment, or other information supplied by an actual canine visitor.

Still, owners report that some dogs follow TV animals with their eyes or look behind the television after the on-screen creatures disappear, suggesting that the boundary can occasionally get fuzzy.

There is much less research on cats. In a study of 125 shelter cats, the animals watched television for only about 6% of the observation period. Moving animals and objects attracted more attention than people or a blank screen, but interest declined over time. Cats, it seems, are perfectly capable of getting bored with the programming — just like they can get bored with humans in general.

Parrots may be more discerning screen users. In one experiment, pet parrots learned to select other birds on a tablet and initiate video calls. A later study found that they initiated more live calls than prerecorded ones, suggesting that genuine interaction held a special appeal — the avian equivalent of preferring Zoom or FaceTime to television.

So if you own a parrot, you won’t have to fight over the remote, but you may have to shush them when your favorite show is on.

Short Answer

Dogs and cats can see television images, but color, sharpness, and motion look different to them — namely because TVs are designed with human vision in mind, and animals don’t see the world exactly the same way as us. Less research exists on cats, but dogs appear to recognize animals and follow action on-screen, although they don’t necessarily experience a televised object as identical to the real thing.

SCIENCE

Why Do Your Ears Pop When Flying?

Credit: Victoria Dokukina/Unsplash.com

By September 22, 2026 Updated: September 23, 2026

Ear discomfort during a flight is a common annoyance, whether you’re a frequent flyer or generally try to avoid the airport. As a plane’s wheels lift off and the skyline tilts, suddenly your sense of sound feels muffled, as if you stuffed cotton balls into your ears.

Maybe you force a yawn. Maybe you chew a piece of gum. Then: sweet relief, as a small “pop” returns your hearing to normal. Where’d that pop come from? Come to think of it, why did your ears get clogged in the first place?

You might already vaguely know the answer: something to do with air pressure. But what does that mean? What exactly is going on inside your ears as you fly?

Meet Your Middle Ear

Diagram of the inner ear — Credit: How Everything Works

That popping sensation comes from air pockets in your ears working to keep the pressure around your eardrums equalized. Those air pockets — small chambers behind each eardrum, one in each ear — are part of your middle ear.

Unless you’re on a flight or winding through mountain roads at higher altitudes, chances are you don’t notice they exist. That’s because your middle ear is normally filled with air at the same pressure as the world around you. A narrow passage called the eustachian tube connects each middle ear to the back of your throat, and its job is to keep that pressure balanced.

Flying disrupts that balance. As the plane climbs in altitude, the air pressure in the cabin drops. Pressure goes hand in hand with how dense air is, i.e.how close its molecules are packed together. When air gets “thin” at higher elevations, it’s because there’s more space between molecules.

Molecules are pretty small, but they still have mass and weigh us down — we’re just used to it. When there are fewer of them — when the air is thinner — that pressure pressed down on us is lower.

Picture air molecules as M&M’s. One by itself isn’t very heavy, but you could tell the difference if you were holding 10 at once versus 1,000. Your hand will feel heavier with the denser concentration of 1,000 M&M’s because they’re exerting more pressure on your palm.

Instead of your hand, air molecules are pushing onto your entire body, and making their way into your ears. But as air pressure drops while your plane ascends, the air already in your middle ear remains at a higher, ground-level pressure. It’s denser and heavier with air molecules, so it pushes outward against your eardrum, which helps translate sound waves into vibrations for your brain, causing that muffled feeling and affecting your hearing.

While descending, the opposite occurs: Cabin pressure rises faster than the air in your middle ear can adjust, so the eardrum gets pushed inward instead. Whether you’re taking off or landing, your eustachian tube solves the problem by opening and allowing air to flow in or out of the middle ear, equalizing the pressure on both sides of your eardrum. That’s when you’ll get the (often satisfying) pop.

It’s like when you tightly press a lid onto a Tupperware container, trapping air inside and raising its internal pressure. The higher density of air bulges the plastic outward, where the surrounding pressure is lower. “Burping” the container by lifting the corner a bit acts like your eustachian tube, releasing the trapped air to equalize pressure with the kitchen.

Pop Science

Person pressing their nose with both hands — Credit: Josue Michel/Unsplash.com

For most people, the discomfort is brief, lasting between a few seconds and a couple of minutes, resolving on its own without lasting effects. Want to help the ear-popping process along? There are a few tricks that help. Yawning and swallowing activate muscles that open the eustachian tube; that’s why chewing gum or sipping water during takeoff and landing also works well, since both encourage you to swallow regularly.

Another method worth a try is the Valsalva maneuver. With your mouth closed, pinch your nose shut and gently blow, as if trying to exhale through your nose. It pushes enough air into the middle ear to encourage the eustachian tube to open.

That trick doesn’t guarantee success, though, especially if you’re sniffling from a cold or allergies. Congestion swells the tissue lining your nose and throat, which can block or narrow the eustachian tube.

That’s why a stuffy nose can turn a routine flight into an uncomfortable experience, and why frequent flyers with allergies may keep decongestants in their carry-on.

Short Answer

Your ears pop when flying because cabin air pressure changes faster than the air pressure in your ear can adjust. As the plane climbs or descends, that mismatch pushes against your eardrum, creating discomfort and muffled hearing. The pop happens when your eustachian tube — a small passage connecting your middle ear to your throat — opens and lets air flow through to equalize the pressure. Swallowing, yawning, and chewing gum can help trigger that release, though colds and allergies can make it harder by blocking the tube.

HEALTH

Why Does Your Body Age?

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By September 22, 2026 Updated: September 23, 2026

At some point, birthday candles stop being the only evidence that another year has passed. Hair silvers, skin gets more character, and recovering from a late night becomes a multiday project. The signs of aging happen to everyone who lives long enough, even if some seem to hide it better than others.

Yet aging isn’t as easy to explain as you might expect. After all, the human body is constantly repairing injuries and fighting off threats — a cut on your hand may be gone within a week, with no scar, and you’d never even know it was there. So why can’t your body keep restoring itself indefinitely?

When the Repair Crew Falls Behind

Grandparent outside with grandchildren — Credit: Nikoline Arns/Unsplash.com

There are really two ways to think about this puzzle. The first is almost existential: Why does aging have to happen at all? If evolution is driven by natural selection — survival of the fittest — why would organisms in nature develop processes that eventually make them weaker?

The answer is that aging is a trade-off. Aging probably arose as a side effect of evolution, rather than a helpful feature. Natural selection strongly favors traits that help organisms survive and reproduce: Giraffes grew long necks to reach food that other animals couldn’t; bats living in the dark learned to see with their ears.

But its influence weakens later in life, because these traits merely improve your ability to reproduce, not live forever. Once an animal has reproduced, evolutionarily speaking, its job is done. You can keep doing what you’re doing, or retire early, or start wrestling lions for fun — evolution doesn’t care at this point.

As a result, genes that may lead to issues at older ages are passed on rather than gradually weeded out. Evolution may also favor genes that provide an early-life advantage even if they cause trouble later on — a bit like accepting a great introductory offer that will eventually jack up the interest rates down the line.

The second riddle is how aging happens: What actually causes our bodies to gradually lose vim and vigor? This question is so complicated that by 1990, one researcher had already counted more than 300 theories. Today, scientists generally think that aging results from numerous biological processes that overlap and interact.

One important factor is accumulating damage to our DNA, the molecule that contains our genetic instruction manual. DNA is a chain of chemicals — you can probably picture its double-helix shape. This chain is constantly disrupted by sunlight, chemicals, and even ordinary activity inside cells, leaving it sort of like a zipper with disjointed teeth that starts snagging.

By one estimate, this damage happens a million times a day. The body mops up most of this damage — a sunburn (which is severe damage to your skin’s DNA) will fade, for instance. But the body’s maintenance systems aren’t perfect. Over many years, unrepaired errors can build up, interfering with cells’ ability to do their jobs.

Illustration of telomeres — Credit: designua/stock.adobe.com; Illustration How Everything Works

Some research has focused on the role of telomeres, the protective caps at the ends of chromosomes. Telomeres are often compared to the plastic tips on shoelaces because they keep chromosomes from becoming damaged or tangled. Every time a cell divides, however, the telomeres become a little shorter. When telomeres become too short, a cell stops dividing.

Some cells that stop dividing die, while others enter a state called senescence. These “retired” cells don’t always relax quietly: They may release substances that promote inflammation and harm neighboring cells. As senescent cells accumulate, they can interfere with the functioning of tissues and organs.

Other age-related changes affect mitochondria, the tiny structures inside cells that produce energy. As mitochondria become dysfunctional, they can disrupt several processes that cells need to work properly. Additionally, the body’s stem cells — which produce fresh cells for muscles, blood, skin, and other tissues — can also become depleted or less effective. Meanwhile, age-related changes can affect which genes cells turn on and off, sometimes causing them to follow the wrong instructions at the wrong time.

None of these processes operates alone. Aging is less like a single clock counting down and more like a repair crew gradually falling behind as small problems pile up. Genetics, environment, lifestyle, and chance all help determine how quickly that happens — which helps explain why growing older looks different for everyone.

Short Answer

Aging happens as damage and other changes accumulate in our cells and DNA, making the body less effective at maintaining and repairing itself. Because aging mostly occurs after an organism reproduces, species haven’t evolved ways to slow it down or stop it.

HEALTH

Why Do You Forget Your Dreams After Waking Up?

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By September 22, 2026 Updated: September 23, 2026

You’ve just survived a shipwreck, reunited with your childhood dog, and discovered a secret room behind the refrigerator. Then, you wake up. For a few moments, the entire adventure seems perfectly clear, as if it actually happened just a few seconds earlier. But as you reach for your phone or start thinking about coffee, the details dissolve.

Dreams can occur during any stage of sleep, although the longest and most vivid are often associated with rapid eye movement (REM) sleep. If you wake up during or immediately after REM sleep, you have a better chance of remembering what you were dreaming. But even then, the memory can vanish almost instantly.

Dream memories are notoriously fragile, and scientists are still teasing out exactly why. The answer likely has to do with what our brains are good at doing while we’re asleep — and what they’re not so good at.

Written in Disappearing Ink

Person in bed stretching — Credit: Andrej Lišakov/Unsplash.com

In order to remember something, you have to do more than just experience it. For a memory to stick, your brain has to transfer that experience from the moment you’re having it into your brain’s storage vaults, metaphorically speaking. Otherwise, no matter how distinctive or fascinating the event may be, it will remain only a fleeting blip.

While we’re asleep, our brains do a fantastic job of generating vivid, rich, bizarre, and sometimes emotionally intense narratives. You might find yourself having a heartfelt conversation with a late relative, for example, or accepting an award from a roomful of raccoons. But the sleeping brain doesn’t do such a great job at reliably encoding those internally generated narratives as long-term memories.

One possible reason has to do with neurons found deep inside the brain. During REM sleep, brain cells that produce a molecule called melanin-concentrating hormone (MCH) become especially active. These cells send signals to the hippocampus — a part of the brain that helps form memories — that appear to reduce its activity.

In a 2019 mouse study, activating these MCH-producing neurons worsened the animals’ memory of information they had learned while awake. The researchers speculated that MCH activity might similarly prevent dream content from being stored in the hippocampus, causing it to be quickly forgotten. It’s a bit like someone deliberately disabling the “save” function in an application on your computer, or covering your filing cabinet with tape so you can’t pry it open.

Illustration of hippocampus — Credit: Dr Faiz/stock.adobe.com; Illustration How Everything Works

Another biochemical called norepinephrine may also play a role. While you’re awake, it helps the brain pay attention to important experiences and turn some of them into lasting memories. During REM sleep, however, the neurons that supply most of the brain’s norepinephrine become almost completely silent (almost as if they need a good night’s sleep themselves).

Conversely, levels of another chemical neurotransmitter called acetylcholine are high during REM, keeping the brain active enough to produce vivid scenes, sounds, and emotions. This combination might be part of what allows dreams to feel so real without making them easy to preserve.

These mechanisms probably only tell part of the story, since other parts of the brain also work differently while we’re asleep. Dream recall also varies considerably from person to person. Some people rarely remember dreaming, while others regularly recall several dreams a night.

What happens right after waking matters, too. If you want to better recollect your dreams, try taking a few minutes after you wake up to deliberately recall them — you may be glad you did. That dream that was hard to remember may turn out to be unforgettable.

Short Answer

Scientists don’t know exactly why dreams disappear from your waking mind so quickly, but several mechanisms likely contribute, including the unique biochemistry of the brain during REM sleep — the stage when most dreaming occurs. The levels of certain neurotransmitters and hormones increase while others decrease, allowing the brain to produce vivid dream experiences but hindering its ability to form and store memories.