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How Does Scratch and Sniff Work?

Scratch and sniff was born of the noble endeavor of making copies. In the dark ages before word processors, inkjet printers, and the Xerox machine, copies of documents were made by placing carbon paper between the sheet you were typing on and the sheet that would become the copy. In the early 1960s, an organic chemist at 3M named Gale Matson developed a way to make ink copies without carbon paper, using a process called microencapsulation.

The Matson process uses two sheets of paper "“ one for the original document and one for the copy "“ on top of one another. The top sheet of paper is coated with microcapsules of colorless ink. When someone writes or types on the paper, the capsules break and release their ink, which mixes with a developer chemical on the second sheet to create a copy.

Not wanting Matson's technology to be a one trick pony, 3M began to search for alternate uses for micro-encapsulation and found that it could be applied to scented oils as well as ink. Scratch 'N Sniff debuted in 1965 and is found in various forms, from stickers to pull-apart perfume sample strips and beyond.

How It Works

1. Scented oil is mixed with a solution of water and water-soluble (capable of being dissolved in water) polymer (3M uses polyoxymethylene urea) in a large vat called a reactor.

2. The mixture is blended at a high speed by a rotary blade. As the oil and polymer solution mix, the oil breaks into very small droplets. After about 12 hours of blending, the droplets are about 20 to 30 microns in size, invisible to the naked eye.

3. When the droplets are the right size, the blending is stopped and a chemical catalyst is added. The catalyst causes the molecular weight of the polymer to increase and become water insoluble. The polymer precipitates out of the water and forms a shell around, or encapsulates, each individual droplet of oil.

4. The reactor is stopped, and the microcapsules are collected and washed to remove any unreacted or unencapsulated materials.

5. The capsules are placed in a tank and mixed with a water base and an adhesive, forming a thick slurry.

6. The slurry is ready to be applied to paper, and there are four basic methods for doing this: silk-screening, web offset printing, flexo-graphic printing (this is what is used for scratch and sniff stickers) and extrusion (a fairly complex printing method used for making perfume and cologne sample strips).

Smelling the finished product is just like smelling anything else. When we scratch the surface of the paper, the microcapsules break and the scented oil travels to our nasal cavity, where the molecules are detected by the olfactory sensory neurons in the olfactory epithelium. A signal is sent to the brain, which translates it, and then we say, "Oooh, banana!"

Click & Sniff

We've come a long way since the birth of Scratch 'N Sniff, and now we don't need micro-encapsulation to smell exotic scents whenever we want. Heck, we don't even need to scratch. Here are some more recent developments in digital scent technology.

DigiScents Inc. in Oakland, California, created the iSmell scent synthesizer. You insert a scent cartridge into the iSmell, which is connected to a computer or video game console, and it releases the scent in short bursts at appropriate times, i.e. when you're playing a first person shooter and get into a firefight, you'll actually get whiffs of gunpowder as you fire rounds. Before you get too excited, PC World named the iSmell one of the 25 Worst Tech Products of All-Time.
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ScenTeck Technologies' Scratch-N-Sniff Pro software and System Scent Card replace the standard vibrating sound waves coming from computer speakers with unique vibrating tones that the brain recognizes not as a sound, but a scent.
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Unleashed, an album by Savannah, Georgia-based musician Zan, is the world's first scent-enabled CD. A gadget called a Scent-Dome plugged into your computer reads code embedded in the CD and releases different scents as the songs play.

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Big Questions
Why Is a Pineapple Called a Pineapple?
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by James Hunt

Ask an English-speaking person whether they've heard of a pineapple, and you'll probably receive little more than a puzzled look. Surely, every schoolchild has heard of this distinctive tropical fruit—if not in its capacity as produce, then as a dessert ring, or smoothie ingredient, or essential component of a Hawaiian pizza.

But ask an English-speaking person if they've ever heard of the ananas fruit and you'll probably get similarly puzzled looks, but for the opposite reason. The average English speaker has no clue what an ananas is—even though it's the name given to the pineapple in almost every other major global language.

In Arabic, German, French, Dutch, Greek, Hebrew, Hindi, Swedish, Turkish—even in Latin and Esperanto—the pineapple is known as an ananas, give or take local variations in the alphabet and accents. In the languages where it isn't, it's often because the word has been imported from English, such as in the case of the Japanese パイナップル (painappuru) and the Welsh pinafel.

So how is it that English managed to pick the wrong side in this fight so spectacularly? Would not a pineapple, by any other name, taste as weird and tingly?

To figure out where things went wrong for English as a language, we have to go back and look at how Europeans first encountered the fruit in question, which is native to South America. It was first catalogued by Columbus's expedition to Guadeloupe in 1493, and they called it piña de Indes, meaning "pine of the Indians"—not because the plant resembled a pine tree (it doesn't) but because they thought the fruit looked like a pine cone (umm, ... it still doesn't. But you can sort of see it.)

Columbus was on a Spanish mission and, dutifully, the Spanish still use the shortened form piñas to describe the fruit. But almost every other European language (including Portuguese, Columbus's native tongue) decided to stick with the name given to the fruit by the indigenous Tupí people of South America: ananas, which means "excellent fruit."

According to etymological sources, the English word pineapple was first applied to the fruit in 1664, but that didn't end the great pineapple versus ananas debate. Even as late as the 19th century, there are examples of both forms in concurrent use within the English language; for example, in the title of Thomas Baldwin's Short Practical Directions For The Culture Of The Ananas; Or Pine Apple Plant, which was published in 1813.

So given that we knew what both words meant, why didn't English speakers just let go of this illogical and unhelpful linguistic distinction? The ultimate reason may be: We just think our own language is better than everyone else's.

You see, pineapple was already an English word before it was applied to the fruit. First used in 1398, it was originally used to describe what we now call pine cones. Hilariously, the term pine cones wasn't recorded until 1694, suggesting that the application of pineapple to the ananas fruit probably meant that people had to find an alternative to avoid confusion. And while ananas hung around on the periphery of the language for a time, when given a choice between using a local word and a foreign, imported one, the English went with the former so often that the latter essentially died out.

Of course, it's not too late to change our minds. If you want to ask for ananas the next time you order a pizza, give it a try (though we can't say what you'd up with as a result).

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Big Questions
Why Do They Build Oil Rigs in the Middle of the Ocean?
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Ryan Carlyle:

We put the rigs where the oil is!

There aren’t any rigs in the “middle” of the ocean, but it is fairly common to find major oilfields over 150 km off the coast. This happens because:

  • Shallow seas often had the correct conditions for oil formation millions of years ago. Specifically, something like an algae bloom has to die and sink into oxygen-free conditions on the sea floor, then that organic material gets buried and converted to rock over geologic time.
  • The continental shelf downstream of a major river delta is a great place for deposition of loose, sandy sediments that make good oil reservoir rocks.

These two types of rock—organic-rich source rock and permeable reservoir rock—must be deposited in the correct order in the same place for there to be economically viable oil reservoirs. Sometimes, we find ancient shallow seas (or lakes) on dry land. Sometimes, we find them underneath modern seas. In that latter case, you get underwater oil and offshore oil rigs.

In the “middle” of the ocean, the seafloor is primarily basaltic crust generated by volcanic activity at the mid-ocean ridge. There’s no source of sufficient organic material for oil source rock or high-permeability sandstone for reservoir rock. So there is no oil. Which is fine, because the water is too deep to be very practical to drill on the sea floor anyway. (Possible, but not practical.)

This post originally appeared on Quora. Click here to view.

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