A lot of people think the hole in the cap of a ballpoint pen is there to keep the pen from drying out, or that it’s there to keep a pressure balance that prevents the pen from leaking. The real reason it’s there is much more straightforward:
It’s there to lower the risk of suffocation. If a small child was chewing on the cap and choked on it, the hole keeps their airway from closing up entirely.
2. Ever notice the little holes in the windows of airplanes?
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That little hole is there for two reasons:
The first reason is to compensate for air pressure. When the plane climbs to cruising altitude, there’s a huge pressure difference between the inside and outside of the plane. The hole is there to regulate some of that difference so that the outer window doesn’t have to do all the work.
The other reason is that it prevents the windows from fogging up.
3. You know that extra piece of fabric that comes with new clothes?
You probably always thought it was there for patches, right? Wrong! The manufacturer includes that little sample of material so you can test how different laundry detergents will react to your new garment.
4. And this little pocket on your jeans?
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The purpose of that little pocket is obvious to any Wild West cowboys or 19th-century gold miners reading this. It’s where you kept your pocket watch when jeans were first invented.
5. Okay, but what about the studs?
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When Levi Strauss made his first pair of jeans, it was a pretty common problem for the seams of the trousers to tear due to the stress being put on them by the workmen and miners who wore them.
This one is going to blow your mind. The hole’s primary purpose to strain the pasta and let the water drain out, but on many spoons, the hole is just about the size of one person’s portion of spaghetti.
11. What’s that arrow next to your gas gauge there for?
Maybe you’ve never even noticed it before, but that little arrow is secretly the most convenient feature on any car. It indicates which side of the car the gas cap is on. Believe me, it comes in handy when you’re driving a rental car.
12. Why is one side of a bobby pin bent into a zigzag?
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That’s an easy one! The grooved side is the bottom of the pin and should face toward the scalp. The grooves help the hairpin hold the hair better.
13. Ever notice a little hole in the bottom of a padlock?
That little hole is there for a few reasons. The first is that it lets water drain out of the lock if you’re using it outdoors, so it won’t rust in the rain or freeze and break in the winter. The hole can also be used to oil the lock to keep it working well.
14. What about this thick bit found on many cables?
Those little cylinder-shaped lumps are ferrite cores or chokes, and they’re essentially just chunks of magnetic iron oxide that are there to suppress high-frequency electromagnetic interference.
Have you ever heard weird interference when your cell phone goes off too close to a speaker? Well, ferrite cores are there to keep that from happening to your monitors, power supplies, and everything else.
15. Do you even know how utility blades work?
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Take a close look at the blade on your box cutter or utility knife. Notice the little score lines? You can break off the end of the blade to give yourself a fresh, sharp blade whenever you want.
To do so, take that back cap off, slide the blade out the back end, and use the cap to snap off the end of the blade before putting it all back together again.
16. And why do some caps have a little spike in them?
Unscrew the lid, flip it around, and push it in. The little spike will punch right through the protective foil on a new container.
17. And the little bumps on the “F” and “J” keys on a keyboard?
Most trained typists will already know what they’re there for. In 10-finger typing, the “F” and “J” keys are the home keys, where your index fingers rest. The little bumps let you find your way back to the home position without looking down at your keyboard.
The wings flip up to give you something to wrap the cable around. Start by wrapping the thicker section of cable around the power block, then the thinner part of the cable around the wings, and secure the whole thing with the little clamp on the very end.
20. And while we’re at it, what’s the dot next to the camera on an iPhone for?
Maybe you’ve noticed the little indentation on the lid of a package of Tic Tacs before and figured it was there to tightly seal the container, right? Well, it also serves as a dispenser that gives you one Tic Tac at a time.
22. And the little disc under the lid of a plastic bottle?
You’ve always heard that it could erase pen ink. Well, it can. But it only really works on very strong, thick paper.
The blue side is harder and more abrasive that the softer pink side, and takes a lot more paper off when you use it, which is why you’ve probably erased clean through the paper any time you’ve tried to use it.
24. And why do wine and champagne bottles have those indentations in the bottom?
It’s not there so that the sommelier can get a better grip while they’re pouring, which is probably what you’ve always heard.
It’s actually there to compensate for the pressure that the contents of the bottle go through during the corking process. The sides and bottoms of bottles are weak spots, and the indentation helps evenly distribute the pressure inside the bottle. That’s why it’s so much deeper on champagne bottles, which are under much more pressure due to the carbonation.