Hi, I'm John Green, welcome to my salon. You certainly have a lot of muscles, sir. This is mental_floss.

So, when it comes to measurement, we have a lot of words that mean, like, a bunch of stuff, or a bit of something, but many of those terms have actual, specific meanings. And today, we're going to learn about a whole barrel full of them.

[mental_floss Intro]

1. When you're talking about oil, a "barrel" is exactly 42 gallons. For beer, a barrel is 31.5 gallons. For dry goods, it's 105 quarts.
That keg of Natty Light at that party that you didn't get invited to is half a barrel.

2. Then there's the "dash", as in, "just a dash of salt," which, according to kitchen supply makers means exactly 1/8 of a teaspoon.

3. "Pinch" is half a dash, or 1/16 of a teaspoon, while

4. the "smidgen" is a half of a pinch, 1/32 of a teaspoon.

5. Butter is packaged at 48 "pats" per pound, which means that each pat is 1/3 of an ounce.

6. This teacup holds exactly one "drop" of tea. How much is a drop? At least to a pharmacist, a drop is exactly 0.05 milliliters, which is really all the tea you need.....I can't even try, I can't even pretend to drink from it...

7. We don't measure measure rain by drops, but in Australia, they used to measure rain by "points". A point was about a quarter of a milliliter, so you might say, "We got a hundred points of rain last night!" That would only be one inch, but it sounds like the kind of terrifying storm that the Weather Channel would give like a name to, like, "Winter storm Aloysius is upon us!"

8. The "jiffy" - or is it giffy? - is a unit of time used in computer engineering that has to do with a computer's clock cycle. It's about 10 milliseconds. It means something even faster in physics, where a jiffy is a unit of measurement for the time it takes for light to travel a distance the size of a nucleus.

9. Physicists also have the "shake", used to measure nuclear reactions. By the way, that's also the stuff at the bottom of your basket at Long John Silver's. A shake takes 10 nanoseconds, or 10 billionths of a second. For context, I will now disappear for a million shakes. And I'm back.

10. We don't know exactly how "hogshead" came to be the name for a measurement of wine, 63 gallons of it to be exact, and I don't think we want to know.

Oh, that reminds me! Every time I mention hogs, I have to put a quarter in the staff pork chop picnic jar.

11. If you've got two hogsheads, that's called a "pipe",

12. or a "butt". So, when someone tells you that they drank a buttload last night, they are either lying or dead.

13. "Megadeth" is not just the third greatest heavy metal band of all time. It's also a terrifying unit of measurement. Also, Meredith's high school nickname. Megadeath, Mere-death, you can figure it out. Anyway, it was coined in the 50's as a unit of atom bomb destruction. One megadeath is equal to one million deaths.

14. On the other end of things, we've got the "micromort", a unit for measuring the statistical probability of death. One micromort is a one in a million chance of death. So, smoking 1.4 cigarettes, or spending an hour in a coal mine increases your risk of death by precisely one micromort. Going skydiving? Seven micromorts. Micromorts: The coolest thing - and also the only cool thing - ever invented by actuaries.

15. So you've heard of horsepower, but did you know there's also a measurable unit of "manpower"? I mean, just look at me, how could there not be? It was worked out to somewhere between an eighth and a tenth of a unit of horsepower. Horsepower was based on the fact that the average brewery horse could lift 330 pounds 100 feet in one minute, stop, and do it again for eight hours. And it would take about eight to ten men to do the same, so your Camaro might have a 300 horsepower engine, but my Chevy Volt has like a 2,000 manpower engine.

16. We also, of course, measure things using the names of famous people. A "Darwin", for instance, is a special ratio for measuring the rate of evolution. Evolution happening at the rate of one Darwin would change something by a factor of about 2.7 over a million years.

17. A "Galileo" is a unit of measurement used by geologists to talk about gravitational acceleration, but because there's only about a seven Galileo difference between the lowest and highest possible measurements on Earth, calculations are usually done in milli-Gals. Milli-Galileos. No, Mark, smaller. Smaller. Small - aww, da's so cute.

18. There's another guy you might have heard of who gave his name to a unit of measurement having to do with your computer mouse. The smallest detectable movement of a computer mouse - somewhere around a tenth of a millimeter - is called a "Mickey".

19. After half a million people followed Wil Wheaton on Twitter, John Kovalic dubbed that number a "Wheaton". Today, the beloved Actor and brewmaster [who is twice the size of Jean-Luc Picard] actually has more than 4.5 Wheatons.

20. Speaking of great men with facial hair, a "beard-second" is the average length a man's beard grows in one second, but beard growth experts disagree on what that length actually is. Some say it's ten nanometers. Some say it's five. Some say, "I can't believe that we're spending our time talking about this."

21. Helen of Troy's magnificent mug is said to have launched a thousand ships, but what if there's just one ship that needs help getting out of port? Then, you need a "milliHelen", the amount of beauty required to launch a single ship.

22. A few hundred years ago in England, small objects were measured in "barleycorns", as in grains of barley. A barleycorn was a third of an inch,

23. and if you needed something smaller than that, you could measure by "poppyseeds", defined as either one fourth or a fifth of a barleycorn.

24. In fact, grain is the basis of our whole system of terms for measuring weight.

25. A "pound" was originally defined as the weight of seven thousand grains. That grain was a grain of - you guessed it - barleycorn, and in the rest of Europe, they used a smaller wheat grain for their measurement system, and our systems have been out of sync ever since. They eventually decided to go to the standards-based metric system, but we stuck with the barleycorn!

26. A "span" isn't just a vague term for long something is, like a bridge or wings or the length of time you can pay attention to something; it originally meant a distance of about nine inches, or the width of a man's hand with the fingers out. That may seem vague to you, but it is literally exactly nine inches! I am the perfect, average person, when it comes to hand span.

27. Besides the span, we also have the "hand", now mostly used for measuring horse height. It's the width of your hand with the fingers closed. But these days, it just means four inches no matter how gigantic your hands are.

28. "Finger" has been used a lot as a unit of measurement, but it's not always clear whether we're talking about the width of the finger, like when your bartender pours you two fingers of booze,

29. or the length, which is a cloth measurement.

30. A "nail" of cloth, which is based on the length of your finger from the nail to the second joint is half a finger, or two and one quarter inches.
So, there you have it. There are about seven barleycorns in a nail, two nails in a finger, four fingers on your hand, and three hands in a foot.

31. And now let us discuss "centipawns". Chess computer programs can evaluate the value of a particular piece or position in terms of hundredths of a pawn, or centipawns.

32. You've heard of the boring old calorie, a unit that measures energy that produces heat. A Big Mac, for instance, has 550 of them. But, what about the energy to cool something? That unit of refrigeration is called a "frigorie", which fell out of use in the 1970s. Since then, we haven't cared how much energy it takes to cool something. We're in favor of it.

33. Also lost to history is the "oxgang", a unit for measuring the area of land approximately equivalent to fifteen acres. Or the amount of land that a farmer could plow with an ox.

34. Luckily, we've still got the melodious "olf". Olfs are used for measuring the air quality of indoor spaces, like offices. One olf is basically the amount of odor of one standard person. So, what's a standard person? The olf standard is a person with a skin area of 1.8 square meters, who bathes 0.7 times per day, and is seated comfortably in a comfortable temperature. Do a bit of activity, and it rises to 5 olfs. A heavy smoker gives off 25 olfs while smoking and six while not. And Alf? Well, his fur traps a lot of odor and he eats cats constantly, so he's like a million olfs.

35. And now we return to the salon to discuss the shortest unit of musical time, the 64th note, or the "hemidemisemiquaver". There are even tales of a shorter note, a 128th note called a "quasihemidemisemiquaver".

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