What Does the Moon Smell Like?: 151 Astounding Science Quizzes (16 page)

submarines. By 1918, they had an apparatus that could detect a submarine 457 metres (1,500 ft) away, and the famous “ping” sound you hear in old subma-OF

rine movies rang out in the real world for the first SCIENCE

time. Twenty years later, the technology was commonly referred to as sonar. Sonar is an acronym, a word made up of parts of other words.

What does sonar stand for?

a) Signal Over NAtural Rate

b) Sonic Output NAval Reflector

c) SOund Navigation And Ranging

d) Submarine Oceanic NAutical Radar

207

The Ping of Sonar

What does sonar stand for?

A

a) Signal Over NAtural Rate

b) Sonic Output NAval Reflector

c) SOund Navigation And Ranging

THE

d) Submarine Oceanic NAutical Radar

SOUNDS

OF

CORRECT ANSWER:

SCIENCE

c) SOund Navigation And Ranging

British scientists called it supersonics at first, but changed the name to ASDics to maintain secrecy. The ASD stood for Anti-Submarine Division. The word sonar was coined in America during World War II, and it’s been with us ever since. Maybe because it’s catchier than ASDics. The physicists who developed submarine-detecting technology had no idea that they were reinventing the wheel, so to speak. The ancient ancestors of today’s toothed whales located submarine life forms (read: lunch) 40 million years ago with biosonar, or echolocation. Whatever you call it, it’s nature’s version of sonar, and it’s still more accurate than manmade technology.

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The Sound of Loud Music

Loudness is measured in decibels, or dB. The range Q

starts at 0 dB, the level of the quietest sound the human ear can detect. A soft whisper is 30 dB.

Normal conversation is around 60 dB. A noisy restau-THE

rant might be 70 dB. Factories are often louder than SOUNDS

80 dB, and if the volume gets higher than 85 dB, ear protection is recommended. Most people set their personal listening devices louder than that. How OF

much louder depends on where you live. In the

SCIENCE

European Union, the maximum volume allowed in

portable music players is 100 dB, but elsewhere, volume is unrestricted. Let’s say you’re listening to your tunes at 100 dB . . .

How loud is your music? It’s actually about

as loud as . . .

a) a low-flying jet

b) operating a chain saw

c) someone shouting in your face

d) all of the above

209

The Sound of Loud Music

How loud is your music? It’s actually about

A

as loud as . . .

a) a low-flying jet

b) operating a chain saw

THE

c) someone shouting in your face

SOUNDS

d) all of the above

OF

SCIENCE

CORRECT ANSWER:

d) all of the above

The chain saw, a low-flying jet, and someone shouting in your face are all around 100 dB. Many personal listening devices go up to 130 dB. That’s more volume than standing in front of the speakers at a loud rock concert, and beyond the point at which sound

becomes painful. As far as your ears are concerned, listening at 100 dB for 15 minutes is the same thing as being exposed to the sounds of a noisy factory, without ear protection, at 85 dB, for eight hours. Like a song, sound isn’t just about volume, it also about duration. The longer you listen, the more it stresses your ears, even at what you might consider to be normal volume. Some experts estimate that one in seven people under the age of 19 already has some form of hearing loss from the sound of loud music.

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The Sound of Snowflakes Falling

How likely is it that two different scientists, one in Q

Canada and one in America, would, within a few

years of one another, discover the sound of

snowflakes falling? It’s happened. What’s more, their THE

finds were weather-related happy accidents. The SOUNDS

Canadian scientist set out to record winter rainfall with an underwater microphone on a lake in British Columbia. When it started to snow, he recorded the OF

sound of falling snowflakes instead. The American SCIENCE

scientists chased a freak snowfall to a motel in Mississippi where they lowered their microphones into the swimming pool. It turns out that it doesn’t matter where they’re recorded. When snowflakes hit the water, there’s no mistaking the sound.

What is the sound of snowflakes falling into water?

a) crash like when you drop a bowling ball

b) fluff like hitting a soft pillow

c) plop like big drops of rain hitting the ground d) screech like a fire engine’s wail

211

The Sound of Snowflakes Falling

What is the sound of snowflakes falling into water?

A

a) crash like when you drop a bowling ball

b) fluff like hitting a soft pillow

c) plop like big drops of rain hitting the ground THE

d) screech like a fire engine’s wail

SOUNDS

CORRECT ANSWER:

OF

d) screech like a fire engine’s wail

SCIENCE

It wasn’t quite what the scientists had expected to hear. They’d anticipated a “plink” sound, and there was one, but it was followed by a screech resembling the wail of a fire engine passing by, and it all happened in less than one ten-thousandth of a second! A likely explanation for the screeching is that when the flakes hit the water, tiny air bubbles get trapped below the surface. The water’s surface tension and pressure make the bubbles vibrate, and they emit a screeching sound before they pop. We can’t hear the screeching of snowflakes without technology, and maybe that’s a good thing. Who’d want to listen to the sound of tiny bubbles screeching like speeding fire engines for hours on end?

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A WHALE WE GO

The Blue Whale’s Brain

Blue whales are the largest animals on the planet, Q

and they may be the biggest creatures that ever lived.

Adults can reach 30 metres (100 ft) in length, and can weigh more than any dinosaur discovered to date.

Although you can’t throw a blue whale on a fish scale, it’s estimated that the biggest ones weigh more than 180 tonnes (200 tons). A big blue whale weighs more than 2,000 large men. Your heart is roughly the size of your clenched fist, but the blue whale’s heart is the size of a small car. Their tongues are huge too, and weigh about as much as an adult elephant. What about their brains? How big could a blue whale’s brain be?

A blue whale’s brain weighs about as much as . . .

a) 1 medium-size red watermelon

b) 4 elephants

c) 7-seat family van

d) 1,000 human brains

213

The Blue Whale’s Brain

A blue whale’s brain weighs about as much as . . .

A

a) 1 medium-size red watermelon

b) 4 elephants

c) 7-seat family van

AWHALE

d) 1,000 human brains

WE

GO

CORRECT ANSWER:

a) 1 medium-size red watermelon

Despite having a car-sized heart, the biggest animal on Earth has a brain that weighs as much as a

medium-size red watermelon, 6–9 kilograms (13–20 lb).

An elephant may weigh as much as a blue whale’s tongue, but its brain, at 5.5–6.5 kilograms (12–14 lb), is in the weight range of blue whale brains. Elephants have the heaviest brains among land animals when it comes to absolute weight, but if you compare brain size to body size, humans are still number one. If blue whales’ brains were as heavy as human brains relative to their body size, their brains would weigh about as much as a seven-seat family van.

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The Whale’s First Cousin

Every living thing on Earth is related, however dis-Q

tantly, because everything evolved from the same early life forms. As living things evolved, and became more complex, some creatures took surprising turns AWHALE

on their evolutionary path. In a way, cetaceans (whales and dolphins) made a U-turn. They were

once aquatic creatures that developed into land ani-WE

mals, and then evolved into aquatic animals again.

GO

Up until fairly recently, there was a lot of speculation, but no proof of their mysterious and fascinating family history. It took genetic testing to reveal who the whale’s closest living relative is.

To which animal are whales most closely related?

a) camel

b) cow

c) hippopotamus

d) wolf

215

The Whale’s First Cousin

To which animal are whales most closely related?

A

a) camel

b) cow

c) hippopotamus

AWHALE

d) wolf

WE

GO

CORRECT ANSWER:

c) hippopotamus

You wouldn’t think it by looking at them, but whales and hippos are first cousins. Their ancient ancestors were land animals that split into two groups about 50

to 60 million years ago. One group went back to the sea and evolved into cetaceans, and the other group stayed on land and evolved into water-loving, pig-like land animals. They were very successful for about 40

million years, but when they died out about 2.5 million years ago, they left just one descendent behind

— the hippopotamus. Hippos are among the biggest and heaviest land animals, but even the biggest hippo is only about as heavy as a newborn blue whale calf.

Hippos aren’t completely aquatic, but they spend more time in the water than most mammals, not

unlike the ancient ancestor they share with their first cousins, the whales.

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The Whale That’s a Whale, but Isn’t

Whales, dolphins, and porpoises all belong to the Q

order
Cetacea
, which comes from the Latin
cetus
, which comes from the Greek
ketos
, meaning sea monster. Cetaceans are divided into baleen whales AWHALE

and toothed whales. Instead of teeth, baleen whales have plates made of keratin, the same stuff that hair and fingernails are made of, through which they WE

filter small aquatic life forms. Toothed whales GO

include dolphins, porpoises, and some whales. They have teeth, which they use to catch fish, squid, and other marine life. Did you know that some of the cetaceans we think of as being whales are actually oceanic dolphins?

Which species is NOT an ocean dolphin?

a) beaked whale

b) killer whale

c) melon-headed whale

d) pilot whale

217

The Whale That’s a Whale, but Isn’t

Which species is NOT an ocean dolphin?

A

a) beaked whale

b) killer whale

c) melon-headed whale

AWHALE

d) pilot whale

WE

GO

CORRECT ANSWER:

a) beaked whale

Beaked whales look like dolphins, but they’re in a different family of the toothed whales. They’re the deepest-diving air-breathing animals known. They’ve been observed going down almost 2 kilometres (1.2

miles), and can probably dive even deeper than that.

Killer whales would more properly be called killer dolphins. They’re the biggest of the ocean dolphins and were originally called whale killers, because they attack and kill other whales. The name got flipped at some point, and they became known as killer whales.

Melon-headed whales and pilot whales are also large marine dolphins.

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Big Melons

Toothed whales have a squishy, fleshy thing on their Q

heads called a melon. If you’ve ever seen a beluga whale, you’ve seen one of the most magnificent

melons of the sea. They’re intelligent animals, so it’s AWHALE

tempting to think that their melons are full of big, bulging brains. But, no, their melons are actually full of oily, fatty stuff. When a beluga, or other toothed WE

whale, vocalizes or sends out echolocation signals, GO

the flexible melon changes shape and acts like a lens to focus the sound into a beam. When an echolocation beam bounces back, it’s intercepted. By what?

Excellent question.

What intercepts a returning echolocation beam? The beluga’s . . .

a) blowhole

b) ears

c) jaws

d) melon

219

Big Melons

What intercepts a returning echolocation beam? The A

beluga’s . . .

a) blowhole

b) ears

AWHALE

c) jaws

d) melon

WE

GO

CORRECT ANSWER:

c) jaws

Toothed whales don’t have external ears, but they do have a hollow lower jaw bone that’s filled with fat, and it does for sound reception what the melon does for transmission. The fatty filling amplifies and conducts the returning sound signal and channels it directly to the middle ear, which sits inside the whale’s head. The middle ear is insulated and protected by a layer of oil and air that prevents sound reception from any bone other than the jawbone. The returning echolocation signals from the middle ear are interpreted by the whale’s brain to form a “pic-ture” of its target object. You could say a toothed whale’s lower jaw functions like ears, making it possible for toothed whales to “see” with sound.

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A Little Echo and a Lot of Location

Echolocation evolved in toothed whales more than 30

Q

million years ago, around the same time that their brains got bigger and their bodies got smaller. It was a big evolutionary leap forward. Dolphin echolocation AWHALE