Collins gem
Imponderables®: Science
David Feldman
Contents
Introduction
What is the difference between “partly cloudy” and “partly sunny” in a weather report?
Why do straws in drinks sometimes sink and sometimes rise to the surface?
Why can’t you see stars in the background in photos or live shots of astronauts in space?
Why do sonic booms often come two at a time?
Why do wintergreen Life Savers sparkle in the dark when you bite into them?
How did Romans do the calculations necessary for construction and other purposes using Roman numerals?
What accounts for the great difference in climate between the Atlantic Coast and Pacific Coast of the U.S.?
If water is composed of two parts hydrogen and one part oxygen, both common elements, why can’t droughts be eliminated by combining the two to produce water?
Why does your voice sound higher and funny when you ingest helium?
Why don’t tornadoes ever seem to hit big buildings or big cities?
Why does rinsing with hot water “set” a stain? Why is rinsing with cold water more effective in eliminating the stain?
How are the first days of winter and summer chosen?
Why do astronomers look at the sky upside down and reversed? Wouldn’t it be possible to rearrange the mirrors on telescopes?
Why does grease turn white when it cools?
Why does menthol feel cool to the taste and cool to the skin?
Why does heat lightning always seem far away? And why don’t you ever hear thunder during heat lightning?
When glass breaks, why don’t the pieces fit back together perfectly?
Why does wood “pop” when put on a fire?
Why does a fire create a crackling sound? Is there any reason why a fire cracks most when first lit?
Who decides where the boundary line is between oceans? If you’re on the ocean, how do you know where that line is?
Why do weather thermometers use red chemical instead of the silver mercury found in medical thermometers?
Why does shampoo lather so much better on the second application?
Why don’t cigarette butts burn? Is there a particular barrier between the tobacco and the filter that prevents the burn?
Why are the oceans salty? What keeps the oceans at the same level of saltiness?
Does it ever really get too cold to snow?
Why does granulated sugar tend to clump together?
Why are rain clouds dark?
Where does the wax go in dripless candles?
If heat rises, why does ice form on the top of water in lakes and ponds?
Why do the clearest days seem to follow storms?
Why do whips make a cracking sound when snapped?
Why don’t planets twinkle at night?
If water is heavier than air, why do clouds stay up in the sky?
What does 0º in the Fahrenheit scale signify?
What does each one-degree increment in the Fahrenheit scale signify?
Why does just about everything look darker when it gets wet?
If all time zones converge at the North and South Poles, how do they tell time there?
How do you tell directions at the North and South Poles?
What are we smelling when it “smells like rain is coming”?
Why do unopened jars of mayonnaise, salad dressing, fruit, and many other foods stay fresh indefinitely on the shelf but require refrigeration after being opened?
How can hurricanes destroy big buildings but leave trees unscathed?
Why does the Moon appear bigger at the horizon than up in the sky?
When you are driving your car at night and look up at the sky, why does it seem that the Moon is following you around?
Why is seawater blue and tap water clear? Why does the color of the ocean range from blue to red?
How can the relative humidity be under 100 percent when it is raining?
Why does the difference between 75 degrees and 80 degrees in water temperature feel quite severe when a five-degree difference in the ambient air barely registers?
What is the official name of the Moon?
What in the heck is a tumbleweed? Why does it tumble? And how can it reproduce if it doesn’t stay in one place?
Why do other people hear our voices differently than we do?
If you dig a hole and try to plug the hole with the very dirt you’ve removed, why do you never have enough dirt to refill the hole?
Why is it that what looks to us like a half-moon is called a quarter-moon by astronomers?
What precisely is sea level? And how do they determine exactly what it is?
Why do peanuts in the shell usually grow in pairs?
Does the Moon have any effect on lakes or ponds? If not, why does it only seem to affect oceans’ tides? Why don’t lakes have tides?
What kind of container holds the rain measured by meteorologists?
Why are cities warmer than their outlying areas?
Why do people look up when thinking?
Why do we itch?
What is the difference between a “mountain” and a “hill”?
What is one hearing when one hears a house “settling” or creaking?
Why do some ice cubes come out cloudy and others come out clear?
What’s the difference between a lake and a pond?
What’s the difference between an ocean and a sea?
What is the technical definition of a sunset or sunrise? How is it determined at what time the sun sets or rises? Why is there natural light before sunrise and after sunset?
What accounts for the varying amounts of static electricity from day to day? Why is there more static electricity in the winter than during the summer?
Why don’t trees on a slope grow perpendicular to the ground as they do on a level surface?
Why are lakes windier at midday than during morning or night?
Where does the moisture go when wisps of clouds disappear in front of your eyes?
Why is the bark of a tree darker than the wood inside?
If nothing sticks to Teflon, how do they get Teflon to stick to the pan?
Why doesn’t glue get stuck in the bottle?
Will Super Glue stick to Teflon?
Why doesn’t a clinical thermometer register room temperature when you take it out of your medicine cabinet?
How do they measure the vitamin content of foods?
Help!!!
About the Author
Copyright
About the Publisher
* * *
INTRODUCTION
* * *
A confession. I spent my entire academic life avoiding science classes. And when I couldn’t avoid required courses, I suffered through them, memorizing lists of species and chemical symbols that I didn’t understand. I thought I wasn’t interested in science.
Then I got into the business of answering mysteries for a living. I’ve devoted the last twenty years of my life to writing books that attempt to eradicate the little mysteries of everyday life that drive us nuts. And more than a few of these questions fell into the realm of science. Even if I wasn’t interested in studying Bernouli’s Principle or Einstein’s Theory of Relativity, I want to know why we look up when thinking, or why the moon seems to follow you when you’re driving on the highway.
I repent. To answer a question about how our world works, you need science. It’s amazing how interesting a subject can be when you actually want to know how to solve a problem. Several of the scientists who I’ve contacted for the ten Imponderables® books confided that they pursued the study of science because they were obsessed with their own Imponderables, little myste
ries that had no practical application.
The good folks at Collins suggested collecting my favorite science Imponderables together for this Gem edition. With a few exceptions, the text is unchanged from the original editions.
Almost all the questions in this book came from readers. Besides the release of psychic stress, the first to pose each mystery received a free, autographed copy of the book. Do you have any Imponderables hounding you, about science or any other subject? You can be rewarded, too. Come join us on the Web at www.imponderables.com, e-mail us at [email protected], or if you must resort to the Imponderable institution known as the United States Postal System, write to us at:
Imponderables
P.O. Box 116
Planetarium Station
New York, NY 10024-0116
* * *
WHAT IS THE DIFFERENCE BETWEEN
“PARTLY CLOUDY” AND “PARTLY SUNNY”
IN A WEATHER REPORT?
* * *
The expression partly sunny was brought to you by the same folks who brought you comfort station and sanitary engineer. As a technical meteorological term, partly sunny doesn’t exist. So while you might assume that a partly sunny sky should be clearer than a partly cloudy one, the two terms signify the same condition. You have merely encountered a weathercaster who prefers to see the glass as half full rather than half empty.
Actually, most of the meteorological terms that seem vague and arbitrary have precise meanings. The degree of cloudiness is measured by the National Weather Service and described according to the following scales:
* * *
Percentage of Cloud Cover
Term
0–30
clear
31–70
partly cloudy
71–99
cloudy
100
overcast
* * *
Where does “fair” weather fit into this spectrum? Fair weather generally refers to any day with less than a 50 percent cloud cover (thus even some “partly cloudy” days could also be “fair”). But even a cloudy day can be termed fair if the cover consists largely of transparent clouds. On days when a profusion of thin cirrus clouds hangs high in the sky but does not block the sun, it is more descriptive to call it a fair day than a partly cloudy one, since one thick cloud formation can screen more sunshine than many willowy cirrus formations.
You might also have heard the aviation descriptions of cloud cover used in weather forecasts. Here’s what they mean:
* * *
Percentage of Cloud Cover
Term
0–9
clear
10–50
scattered clouds
51–89
broken sky
90–99
cloudy
100
overcast
* * *
Not many people know what the weather service means when it forecasts that there is a “chance” of rain. Precipitation probabilities expressed in vague adjectives also have precise meaning:
* * *
Chance of Precipitation
National Weather Service Term
0–20%
no mention of precipitation is made
21–50%
“chance” of precipitation
51–79%
precipitation “likely”
80–100%
will not hedge with adjective: “snow,” “rain,” etc.
* * *
How does the National Weather Service determine the daily cloud cover in the space age? Do they send up weather balloons? Satellites? Not quite. They send a meteorologist to the roof of a building in a relatively isolated area (airports are usually used in big cities) and have him or her look up at the sky and make a well-informed but very human guess.
* * *
WHY DO STRAWS IN DRINKS
SOMETIMES SINK AND SOMETIMES
RISE TO THE SURFACE?
* * *
The movement of the straw depends upon the liquid in the glass and the composition of the straw itself. The rapidly rising straw phenomenon is usually seen in glasses containing carbonated soft drinks. Reader Richard Williams, a meteorologist at the National Weather Service, explains the phenomenon:
…the rise occurs as carbon dioxide bubbles form on both the outside and inside of the straw. This increases the buoyancy of the straw and it gradually rises out of the liquid.
The gas is under considerable pressure when the drink is first drawn or poured. When that pressure is released the gas forms small bubbles on the sides of the glass and on the straw. As the bubbles grow the straw becomes buoyant enough to “float” higher and higher in the container.
Occasionally, though, a straw will rise in a noncarbonated beverage, and we didn’t get a good explanation for this phenomenon until we heard from Roger W. Cappello, president of strawmaker Clear Shield National. We often get asked how our sources react to being confronted with strange questions. The only answer we can give is—it varies. Sure, we like authoritative sources who fawn over us and smother us in data. But we must confess we have a special place in our hearts for folks like Cappello, who make us sweat a little before divulging their secrets. Here is his letter to Imponderables, verbatim, skipping only the obvious pleasantries:
After pondering your question for a while, I decided to toss your letter as I was too busy for this. I later retrieved the letter and decided I would attempt to give you an answer that is slightly technical, mixed with some common sense and some B.S.
First off, I know the action you were referring to had something to do with “specific gravity.” Specific gravity, as defined by Webster, is “the rate of the density of a substance to the density of a substance (as pure water) taken as a standard when both densities are obtained by weighing in air.”
Straws today are formed from polypropylene, whereas many years ago they were made of polystyrene, before that paper, and before that, wheat shafts.
Assuming water has a specific gravity of 1, polypropylene is .9, and polystyrene is 1.04. A polypropylene straw will float upward in a glass of water, whereas a polystyrene straw will sink. However, a polystyrene straw will float upward in a carbonated drink as the carbonation bubbles attach themselves to the side of the straw, which will help offset the slight specific gravity difference between water and polystyrene. A polypropylene straw will float higher in a carbonated drink for the same reason. If you put a polypropylene straw in gasoline, and please don’t try this, it will sink because the specific gravity of gas is lighter than water.
If you lined up ten glasses of different liquids, all filled to the same level, the straws would most likely float at all different levels due to the different specific gravities of the liquids and the attachment of various numbers of bubbles to the straws.
I really wish you hadn’t brought this up as I’m going to lunch now. I think I’ll order hot coffee so I can ponder the Imponderables of my business without distraction.
Good luck.
We can use all that good luck you were wishing us. I’m sure you had a productive lunch, too. Anyone willing to share information with us can eat (and sleep) with a clear conscience, knowing that he has led to the enlightenment of his fellow humans.
Submitted by Merrill Perlman of New York, New York.
* * *
WHY CAN’T YOU SEE STARS IN THE
BACKGROUND IN PHOTOS OR LIVE
SHOTS OF ASTRONAUTS IN SPACE?
* * *
There actually are folks out there who believe that NASA pulled off a giant hoax with the “so-called Moon landings.” Often, the lack of stars in the background of photos of the astronauts is cited as startling evidence to support the conspiracy.
Sheesh, guys. If you want to be skeptical about something, be dubious about whether “When you’re here, you’re family” at Olive Garden, or whether State Farm Insurance will be there for you the next time you’re in trouble. But don’t use a dark background in a pho
to of outer space to convince yourself that astronauts have never gotten farther into space than a Hollywood soundstage.
The answer to this Imponderable has more to do with photography than astronomy. Next time you go to a football game on a starry night, try taking a photo of the sky with your trusty 35mm point-and-shoot camera or camcorder. Guess what? The background will be dark—no stars will appear, let alone twinkle, in the background.
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