Wednesday, June 8, 2016

I Didn't Know That

Why does a tea kettle get quiet just before the water boils?


Dear Cecil:

Why does a teapot make progressively louder noises as it heats up, then suddenly go quiet just before the water commences to boil? --Timothy L., physics department, Johns Hopkins University, Baltimore

Dear Timothy:

Jeez, can't you guys at Johns Hopkins figure out anything? For starters, a teapot doesn't make noise, a teakettle does. The pot is what the water goes in after it's been boiled. As for the noise, it's caused by cavitation, which is a high-tech way of saying bubbles form and then they pop. When you heat water on the stove, the layer at the bottom is the first to boil, meaning it turns into a gas. The water vapor collects into bubbles, which rise toward the surface, passing through cooler water en route. The lower temperature causes the vapor to recondense into liquid and the bubbles collapse, making a noise. This gets gradually louder, as bubble production increases, until the water is so uniformly hot that the bubbles make it to the top without popping. At this point the noise diminishes. But it takes a moment before the vapor pressure builds up sufficiently in the top of the kettle to make it start whistling. That's why you get a brief period of calm before the steam--an incredibly feeble play on words, but a perfectly adequate description of the event.


Why do clocks with Roman numerals use "IIII" instead of "IV"?

Dear Cecil:

I hate to see you wasting your time on the insipid questions your readers have been submitting lately. Permit me to pose a question that will have a meaningful impact on today's social problems: Why do clocks that have Roman numerals on the faces always show the number four as IIII instead of IV? --Jerry M., Hollywood, California

Dear Jerry:

Finally, somebody with a sense of perspective.

I hate to be a wimp about these things, but I'm going to have to fall back on that old standby: They do it that way because that's the way they've always done it, at least as far back as 1550, and probably earlier. Many clock historians claim that IIII is supposed to provide artistic balance, since you mentally pair it off with VIII on the other side of the dial. (Presumably you see how the otherwise economical IV would have trouble holding its own in this respect.) The only problem with this theory is that the Romans apparently never used IV--it's a relatively modern invention. It's possible, in other words, that old-time clock makers used IIII because it was considered perfectly proper usage for all purposes, horological or otherwise, at the time.

My friend David Feldman, in his book Why Do Clocks Run Clockwise, cites an expert who says medieval clockmakers used IIII so as not to confuse the illiterate. You could count, "One, two, three, four! Hey, it's four o'clock!" whereas having to subtract I from V to arrive at the same result was beyond your mental capabilities.
Well, maybe. But let's think about this. The peasants couldn't handle IV, but somehow the IX for 9 posed no problems? Did only literate people go out after eight o'clock? Actually, as I read Dave more closely, he seems to be saying that at one time clockmakers used VIIII for 9. OK, but why do modern Roman numeral clocks use IIII and IX? Tragically, we may never know the truth. History can be like that.


Dear Cecil:

Regarding the use of Roman numeral IIII vs. IV on clocks, I noticed IIII on clocks a long time ago and when I happened to meet a clockmaker, I asked. His conjecture was as follows. Count the number of X's, V's, and I's on a clock face that has IIII. You find you have four X's, four V's, and 20 I's, or four identical sets of XVIIIII. Accordingly, if a metal worker in the early days of clockmaking had to make the numerals, it was easier and less wasteful of material to make four slugs for each clock face, each slug containing one X, one V, and five I's. --Peter L., professor of chemistry, Illinois Institute of Technology, Chicago

Dear Peter:

Could be, but the numbers on many old clocks appear to have been cast in one piece, as opposed to being assembled out of individual characters, as your theory would require. But you--or at least your clockmaker friend--get points for ingenuity. A SITE FOR FOUR I's, PART TWO

Dear Cecil:

I was surprised by your wishy-washy answer regarding the rationale for using the Roman numerals "IIII" on clocks instead of "IV." Long ago I read somewhere (L. M. Boyd?) that, not having a taste for hurled lightning bolts, the Romans were loath to offend the gods' head honcho by daring to place the first two letters of his name (IVPITER in their primitive, pre-U, pre-J script) on a clock face. Accordingly they plumped for the four-eyes. Why the letters would be so offensive I do not recall, but knowing how touchy the gods were, I suppose the clockmakers just figured there was no point taking chances. --E.L.F., San Antonio, Texas

Dear E.:
Fine. Just one problem. The Romans didn't have clocks. They did have sundials, and I suppose--although unfortunately Little Ed prematurely cleaned out the "Timekeeping devices, ancient" GIF file--that they may have used IIII instead of IV to identify the fourth hour. But European clockmakers a thousand years later were under no obligation to do the same, belief in IVPITER having largely evaporated by that time. Maybe they did anyhow, out of some sense that it wasn't wise to buck tradition. Maybe they just thought IIII was the proper way to style a Roman "4," the modern subtractive method (IV) not yet having fully kicked in. Or maybe they just thought IIII made for a more aesthetically pleasing configuration of numbers. The point is we don't know, and given that clockmakers had better things to do than keep notes on such minutiae, we may never know. You may call the disinclination to give a firm answer in the absence of dispositive evidence "wishy-washy"; I call it learning to deal with ambiguity. It's like I said. The Straight Dope isn't just a Q&A column, it's training for life. 

Hints from Somebody

A sealed envelope - Put in the freezer for a few hours, then slide a knife under the flap. The envelope can then be resealed.
Use Empty toilet paper roll to store appliance cords. It keeps them neat and you can write on the roll what appliance it belongs to.
To remove old wax from a glass candle holder, put it in the freezer for a few hours. Then take the candle holder out and turn it upside down. The wax will fall out.
Crayon marks on walls? This worked wonderfully! A damp rag, dipped in baking soda. Comes off with little effort (elbow grease that is!).
Permanent marker on appliances/counter tops (like store receipt BLUE!) rubbing alcohol on paper towel.
Blood stains on clothes? Not to worry! Just pour a little hydrogen peroxide on a cloth and proceed to wipe off every drop of blood. Works every time!

Use vertical strokes when washing windows outside and horizontal for inside windows. This way you can tell which side has the streaks. Straight vinegar will get outside windows really clean. =================================
 Candles will last a lot longer if placed in the freezer for at least 3 hours prior to burning.
To clean artificial flowers, pour some salt into a paper bag and add the flowers. Shake vigorously as the salt will absorb all the dust and dirt and leave your artificial flowers looking like new! Works like a charm!

To easily remove burnt on food from your skillet, simply add a drop or two of dish soap and enough water to cover bottom of pan, and bring to a boil on stove top.
Spray your TUPPERWARE with nonstick cooking spray before pouring in tomato based sauces and there won't be any stains.

To get rid of itch from mosquito bites, try applying soap on the area and you will experience instant relief.
When you get a splinter, reach for the scotch tape before resorting to tweezers or a needle. Simply put the scotch tape over the splinter, and then pull it off. Scotch tape removes most splinters painlessly and easily.
To remove a stain from the bottom of a glass vase or cruet, fill with water and drop in two Alka Seltzer tablets.

All photos © Geonni Banner

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