Quick Thinking: Rapid-Fire Q&A

Hi everyone, welcome to Cold-Knowledge Blind Box. I'm Qiao Yulan, your listener-host.

Have you ever run into some everyday phenomenon or belief, and when you really thought about it, you couldn't say why it exists?

For example, why does scanning a simple QR code unlock all kinds of services? Why does the first thing you think of when eating lychees or oranges be that they'll "heat you up"? And why does your whole body get so itchy once the weather turns cold?

Then there's the "survivorship bias" everyone talks about. And why running your phone battery down to 0% is so damaging to it. And so on.

So today we're doing a rapid-fire Q&A of common-knowledge trivia. In the shortest possible time, we'll help you understand the interesting stories behind some phenomena, giving your thinking a quick jolt of energy.

Let's warm up with the most familiar thing, the QR code. What do you know about QR codes?

The QR code was invented by a Japanese company in 1994, and around 2011, riding the wave of the mobile internet, it swept across China. As the name suggests, the "2D" in QR code comes from the fact that it's a square made of horizontal and vertical lines, which together form an information space. So was the predecessor of the QR code called the "1D code"?

Exactly. A 1D code has only one line. It's also called a barcode, the kind the cashier scans with a handheld device when you check out.

In the era of 1D codes, people often complained that there wasn't enough information. A barcode could only record 25 letters or digits. With the explosion of internet applications today, that amount of information is clearly not enough.

A QR code records information in both the horizontal and vertical dimensions, so its information density is much higher. It can now store thousands of characters. It also has built-in redundancy, which means that even if part of the image is damaged, the code can still be scanned and its content can still come out.

Have you noticed the large dot-like markers in the corners of a QR code? Those are called position detection patterns, and they tell the phone where to start reading the information. This means that when you scan, the phone knows where to begin, so whether you scan it upright, upside down, or at an angle, the phone can still read the content.

In a sense, the QR code is a gateway to the internet. It takes a long string of links, or characters that look meaningless to people but that a machine can understand, and carries them in a neat little square. (It might be a bit claustrophobic, I admit.) People no longer have to type characters one by one into a browser. Adding a friend can be this elegant: scan once, and the result pops up. That's the past and present of the QR code. Did you get it?

Car owners in Guangdong often hear the word "shanghuo," which means "getting heaty." Especially when faced with foods like lychees, oranges, fried chicken, or barbecue, after eating them people are always worried about getting heaty, so they immediately go drink a sip of herbal tea to push that heat down. If you don't, you'll break out in acne, and then coughing and a dry throat show up right away.

Barbecue is understandable, since it's cooked over fire. But how do translucent fruits like lychee and orange flesh get connected with "heatiness"?

It should be noted that "shanghuo" is a concept from traditional Chinese medicine. From the perspective of modern medicine, "heatiness" is essentially an inflammatory response.

The sore, dry throat that follows eating lychees and oranges is caused by taking in too much sugar in a short time. A rapid rise in blood sugar makes insulin spike and forces the pancreas into emergency overtime. The oxidation reactions that metabolize this sugar then increase free radicals in the body, and these free radicals damage cell membranes, triggering a small inflammatory reaction. The throat is also a base camp for immune cells, and white blood cells gather in the throat to surround abnormal cells, and then the body starts coughing.

Why do such small fruits pack so much energy? Because you eat too much. Lychees and oranges are both small, and once you start eating them, it's hard to stop. And these fruits are actually very high in sugar: 100 grams of lychee contains 15 to 20 grams of sugar, and 100 grams of orange contains 8 to 10 grams. By contrast, the so-called "sugar bomb" watermelon has only about 6 grams of sugar per 100 grams of flesh. Plus, watermelon is very watery and fills you up easily, so it doesn't seem to cause heatiness as much.

Barbecue works the same way. It's very high in fat. If the body takes in sugar and fat too quickly in the short term, the pancreas first gets overloaded. Then, metabolizing these nutrients can briefly change the body's hormone levels, and the gut microbiome environment also shifts. That in turn can lead to breakouts and constipation. So in today's age of material abundance, cutting back on these sweet burdens a little can also ease the pressure on the body's hardworking cells.

Once winter arrives, many friends feel their bodies suddenly itch: first the arms, then the thighs. Without any acne, why does the body get itchy so easily in winter? This is because winter air is very dry, which makes moisture on the surface of the body evaporate more easily. Add the drop in temperature, and the skin produces less of its own oil, so its ability to lock in moisture declines. When skin is too dry, it itches easily. In a way, it's also a signal from the body.

That's why products like hand cream and body lotion sell very well in winter. Their principle is to form a protective layer of oil on the body, locking in moisture. But if you can't be bothered to apply these products, another approach might be to reduce how often you shower in winter. I know that's hard for people from Guangdong to accept, though. So another good method is to shower without using shower gel, or without soap, so that the body keeps some of its natural oils, which also reduces dryness.

That's where this rapid-fire Q&A episode of Cold-Knowledge Blind Box ends. If there's any other knowledge you'd like to hear about, you can also open the NIO app, go to the friends section, find the community, and look for NIO Radio's Shenzhen city channel. Let's share the cold facts you love together!

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