The little “why?” questions we suddenly feel in everyday life.
The sights we casually look at, the sounds we hear, and the things we use might hide unexpected meanings and fascinating facts.
So why not use this article to unravel together the mysteries and little-known trivia hiding all around us? There are surprisingly many things that feel so obvious that, when asked, we can’t actually explain them! Welcome to a world of trivia that will make you say “Huh, interesting!” over and over—and give you fun tidbits you’ll want to share with others.
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Everyday little questions! Surprisingly unknown, fun trivia close to home (1–10)
What are the hiragana characters on Japanese license plates for?
Various hiragana characters appear on Japanese license plates.
What do they mean? In fact, those characters are used to broadly categorize the type of vehicle.
For example, “わ” and “れ” are reserved for rental cars, while characters from “あ” to “を” are used for private and commercial vehicles, so you can generally tell how a vehicle is used just by looking.
They’re also distinguished between standard-sized and compact cars.
By the way, hiragana that are easy to misread, such as “お,” “し,” “ん,” and “へ,” are not used.
It turns out that even the things we casually see every day have clear meanings.
What are the bumps on the “F” and “J” keys on a computer keyboard?
I think many of us often use computers for work or hobbies.
The small bumps on the F and J keys of a keyboard are called home position marks.
These bumps let you instantly find where to place your fingers without looking at the keyboard.
By typing from the correct home position, your hands strike from the right posture and unnecessary finger movement is reduced.
This also shortens input time and makes your work more efficient.
It becomes a very important keyboard feature that supports your work from behind the scenes.
Why is air invisible?
Why is air invisible? Have you ever wondered? Because air has no color, we cannot see it.
Nitrogen, which makes up about 78% of air, and oxygen, about 21%, are both colorless.
The remaining 1% includes gases such as argon and carbon dioxide, which are also colorless.
If even one component had color, the air itself would be tinted, but since that isn’t the case, air is invisible to our eyes.
You could say air is highly transparent.
What’s the difference between café au lait and café latte?
When you go to a café, you sometimes see both caffè latte and café au lait on the menu, right? Do you know the difference between the two? Literally, both mean coffee with milk.
However, the origins differ—one is Italian and the other is French.
In Italy, caffè latte refers to a drink made by mixing espresso with hot milk.
In France, café au lait is typically made by combining drip coffee and hot milk, each served from its own pot.
Also, caffè latte generally has a higher ratio of milk than café au lait.
Why do we yawn?
Yawns come on suddenly, don’t they? They happen when you’re sleepy, when you “catch” one from someone else, or even for no particular reason.
The timing varies from person to person, but why do we yawn in the first place? It’s thought that yawning is triggered by the paraventricular nucleus in the hypothalamus.
It’s also said to help the brain switch gears and refresh itself.
Yawning itself isn’t a bad thing, but if you really want to stop one, moving your mouth can help.
Why is it that only the 5-yen and 50-yen coins have holes in them?
It seems there are fewer chances to carry cash these days, but have you ever wondered about something when using coins? Only the 5-yen and 50-yen coins have holes, right? The reason is said to be to prevent counterfeiting and to distinguish them from other similar coins.
Having a hole in the coin makes it harder to counterfeit.
Around 1957, the 100-yen coin, which was introduced after the 50-yen coin, was considered confusingly similar and became an issue.
Also, the 5-yen coin was given a hole to distinguish it from the 1-yen coin.
Unlike the current 1-yen coin, the 1-yen coin that existed around 1948 was very similar to the 5-yen coin at the time.
In addition, punching a hole also helps save on the raw materials used for coins.
How can airplanes fly?
Have you ever looked at an airplane flying in the sky and wondered, “How can that hunk of metal fly?” Paper airplanes are light, so they ride the wind, right? So how do real airplanes fly? Four forces are involved in moving an airplane: thrust, drag, weight (gravity), and lift.
Among these, thrust and lift play especially big roles in keeping an airplane aloft.
The engine generates forward “thrust,” and as the plane moves forward, “lift” arises acting upward from below the wings, causing the aircraft to rise.
Where does dust come from?
Even though you’ve just cleaned, dust somehow piles up before you know it.
Where does dust come from? Dust is made up of shed fibers from clothing, sofas, and carpets, as well as fragments of human skin, dandruff, mold, and bacteria.
It’s said that air currents caused by human movement, temperature differences, and wind from air conditioners or open windows bring these particles together to form dust.
What’s more, mold and bacteria can rapidly multiply within the accumulated dust.
There are also cleaning methods that can help prevent dust from building up, so if you’re interested, try looking them up.
Are traffic lights three colors: red, yellow, and green?
Traffic lights have three colors: green, yellow, and red.
So, why were these three chosen? In fact, these colors are not a Japan-specific rule; they are defined by the International Commission on Illumination.
Traffic signal colors are designated as five colors—red, green, yellow, white, and blue—and three of these are assigned for traffic signal lamps.
In Japan, the green light is commonly called “blue” (ao shingō).
There are various explanations for this, including the broad traditional range covered by the term “ao” (blue/green), the influence of the three primary colors, and the perception that blue is the opposite of red.
Why do cats like boxes?
Cats really do love boxes, don’t they? There are several instinctive reasons why.
First, a box is enclosed on multiple sides, creating a safe, secure shelter that protects them from potential threats.
By rubbing and leaving their scent, they can mark territory and maintain a sense of privacy.
Tight spaces also help them retain body heat, making boxes great for comfortable temperature regulation.
Climbing inside stimulates their playful and exploratory nature, satisfying their curiosity.
It’s also said that boxes reduce outside stimuli, which can help lower stress.
In a way, it’s similar to the human urge to hunker down and cocoon ourselves!