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YouTube // engineerguy

How Retractable Ballpoint Pens Work

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YouTube // engineerguy

We've all used clicky ballpoint pens. I'll admit, I fiddle with one on a daily basis, clicking it over and over—those clicks are very satisfying. But what are the details of the mechanism that allows the tip to be extended or retracted? Although I've taken apart many of my pens (another nervous habit that I enjoy, especially during long meetings), I never spent much time thinking about the engineering involved.

It turns out that there are various different ways to build a retractable pen. But in this four-minute video, we see how the hugely popular Parker Jotter ink pen works, using a series of surprisingly clever cams and a spring. Let Bill Hammack, The Engineer Guy, explain:

Note: If you'd like to read the original patent, Google has it (complete with plenty of minor scanning errors in the text). The illustrations are beautiful.

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This Just In
Want to Become a Billionaire? Study Engineering
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If you want to get rich—really, really rich—chances are, you should get yourself an engineering degree. As The Telegraph reports, a new analysis from the UK firm Aaron Wallis Sales Recruitment finds that more of the top 100 richest people in the world (according to Forbes) studied engineering than any other major.

The survey found that 75 of the 100 richest people in the world got some kind of four-year degree (though others, like Bill Gates and Mark Zuckerberg, attended a university but dropped out before graduation). Out of those who graduated, 22 of those billionaires received engineering degrees, 16 received business degrees, and 11 received finance degrees.

However, the survey doesn't seem to distinguish between the wide range of studies that fall under the "engineering" umbrella. Building a bridge, after all, is a little different than electrical engineering or computing. Four of those 100 individuals studied computer science, but the company behind the survey cites Amazon's Jeff Bezos (who got a bachelor's degree in electrical engineering and computer science from Princeton) and Google's Larry Page (who studied computer engineering at the University of Michigan and computer science at Stanford) as engineers, not computer scientists, so the list might be a little misleading on that front. (And we're pretty sure Bezos wouldn't be quite so rich if he had stuck just to electrical engineering.)

Aaron Wallis Sales Recruitment is, obviously, a sales-focused company, so there's a sales-related angle to the survey. It found that for people who started out working at an organization they didn't found (as opposed to immediately starting their own company, a la Zuckerberg with Facebook), the most common first job was as a salesperson, followed by a stock trader. Investor George Soros was a traveling salesman for a toy and gift company, and Michael Dell sold newspaper subscriptions in high school before going on to found Dell. (Dell also worked as a maitre d’ in a Chinese restaurant.)

All these findings come with some caveats, naturally, so don't go out and change your major—or head back to college—just yet. Right now, Silicon Valley has created a high demand for engineers, and many of the world's richest people, including Bezos and Page, earned their money through the tech boom. It's plausible that in the future, a different kind of boom will make a different kind of background just as lucrative. 

But maybe don't hold your breath waiting for the kind of industry boom that makes creative writing the most valuable major of them all. You can be fairly certain that becoming an engineer will be lucrative for a while.

[h/t The Telegraph]

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science
Here's Why It's So Hard to Achieve the Perfect Temperature While Taking a Shower
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The only thing worse than stepping out of a warm shower into a chilly bathroom is owning a shower that seems to only have two temperatures—scalding or freezing—unless the knob is positioned just so. Curious as to why it’s so hard to achieve bathing nirvana with a simple twist of the wrist? In the video below, SciShow host Stefan Chin broke down the intricacies of home plumbing, and offered advice on how to keep your shower from going from blissfully warm to bitingly cold.

With home water heaters, “adding really hot water to cold water changes the temperature more than adding the same amount of water that’s just warm,” Chin explains. “So if the water is too hot, tiny changes in how much hot water is sent your way can lead to big changes in the temperature of the mixed water hitting your body.”

And “the water in water heaters is usually very hot,” he adds. “It’s generally set to around 50°C [about 122°F] to kill bacteria.”

Meanwhile, some small water heaters simply don’t hold enough hot water at any one time for a long shower—plus, lots of plumbing simply isn’t designed to check the temperature of the hot-cold water balance.

A hot shower is perhaps the simplest—yet most universal—luxury you can enjoy, so you probably don’t want to waste your precious relaxing time fiddling with the dial. (Plus, some creative types find that their best ideas often emerge when they’re relaxed and sudsed up—something that can't really happen when you're being doused with cold water.) Rest assured, Chin has some shower solutions, which you can learn by watching the video below.

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