Wednesday, 10 February 2021

The Secret of How the Titanic Sank

 

The Secret of How the Titanic Sank



New evidence has experts rethinking how the luxury passenger liner sank.

FOR DECADES AFTER THE disaster, there was little doubt about what sank the Titanic. When the "unsinkable" ship, the largest, most luxurious ocean liner of its time, crashed into an iceberg on its maiden voyage in 1912, it took more than 1,500 of its 2,200 passengers to the bottom. As the ship slipped into the North Atlantic, so, too, did the secret of how and why it sank.

Two government investigations conducted immediately after the disaster agreed i was the iceberg, not any weakness in the ship itself, that caused the Titanic to sink. Both inquiries concluded the vessel had gone to the bottom intact. Blame for the incident fell on the ship's deceased captain, E. J. Smith, who was condemned for racing at 22 knots through a known ice field in the dark waters off the coast of Newfoundland. The case of the Titanic was considered closed.

But lingering questions about what might have sunk the seemingly indestructible ship never completely disappeared. In 1985, when oceanographer Robert Ballard, after years of searching, finally located the ship's remains 2.5 miles down on the ocean bottom, he discovered that it had, in fact, broken in two on the surface before sinking. His findings made the Titanic rise again in the public imagination. Why had it cracked, experts wondered? If the official inquiries were wrong, was the invincible Titanic weak? A few years after Ballard discovered the wreck, the first pieces of the ship were brought to the surface, raising even more eyebrows when they seemed to offer physical evidence that low-quality steel might have caused the disaster. In 1997, James Cameron's film Titanic, largely mirroring the scientific consensus at the time, seared Titanic's terrifying last moments, with its stern soaring high into the air before it cracked in two and disappeared, into popular memory.

Still, the search for answers about the Titanic didn't end there. In two new books, a group of historians, naval architects, and materials scientists argue that fresh evidence has further unraveled the familiar story of the Titanic, raising more questions about what caused the disaster. In What Really Sank the Titanic: New Forensic Discoveries, Jennifer Hooper McCarty, a materials scientist at Oregon Health and Science University, and Tim Foecke, a scientist at the National Institute of Standards and Technology, make the case that it wasn't the ship's steel that was weak; it was the rivets, the all-important metal pins that held the steel hull plates together. Titanic's Last Secretsto be published next month, describes the work of Richie Kohler and John Chatterton, wreck-diving historians who believe two recently discovered pieces of the Titanic's bottom prove the ship's stern never rose high in the air the way many Titanic experts, including Cameron, originally believed. The two divers, whose discovery of a lost German U-boat was chronicled in the book Shadow Divers, say the ship broke up and sank while still relatively flat on the surface—a potential sign of weakness, they believe, that was covered up after the disaster.

When the Titanic's keel was laid down in 1909, Harland & Wolff, the Belfast shipbuilder that constructed the ship, certainly didn't believe its design would still be controversial a hundred years later. Built-in response to a rival company's construction of a new generation of fast liners, Titanic and her sister ships, Olympic and Britannic, were the biggest ships ever made—from bow to stern, they were almost 900 feet long, dwarfing even the world's biggest skyscrapers. Specially outfitted to handle the challenges of the North Atlantic, including big waves and major collisions, they were also supposed to be among the safest. The Titanic could stay afloat with four of its 16 watertight compartments flooded, more than anyone could imagine on a ship of its size.

On the night of April 14, 1912, though, only a few days into the Titanic's maiden voyage, its Achilles' heel was exposed. The ship wasn't nimble enough to avoid an iceberg that lookouts spotted (the only way to detect icebergs at the time) at the last minute in the darkness. As the ice bumped along its starboard side, it punched holes in the ship's steel plates, flooding six compartments. In a little over two hours, the Titanic filled with water and sank.

Low quality. More than 70 years passed before scientists were able to study the first physical evidence of the wreck. As luck would have it, the first piece of steel pulled up from the bottom seemed to put an end to the mystery. When the steel was placed in ice water and hit with a hammer, it shattered. For much of the 1990s, scientists thought this "brittle" steel was responsible for the massive flooding. Only recently has testing on other, bigger pieces of the ship disproved this theory. The original piece, scientists discovered, had been unusually weak, while the rest of Titanic's steel passed the tests. "We know now there was nothing wrong with the steel," says William Garzke, chairman of a forensics panel formed by the Society of Naval Architects and Marine Engineers to investigate the wreck.

Experts looking for explanations landed on another potentially weak link: The more than 3 million rivets holding the ship together. McCarty and Foecke began examining 48 rivets brought up from the wreck and found they contained high concentrations of "slag," a residue of smelting that can make metal fracture prone. Researching in the Harland & Wolff archives, they discovered that the shipbuilder's ambitious plans to build three large ships at the same time had put a huge strain on its shipyard. "Not because of cost, but because of time pressures, they started using lower-quality material to fill the gaps," says Foecke. This substandard iron was pounded by hand into the ship's bow and stern, where the large machines required to pound in steel rivets didn't fit. Steel rivets, meanwhile, which are much stronger than iron, were put in the more-accessible middle of the ship.

When the Titanic hit the iceberg, McCarty and Foecke say, the weaker iron rivets in the bow popped, opening seams in the hull—and hurrying the ship's demise. It's no accident, Foecke says, that the flooding stopped at the point in the hull where the steel rivets began.

Wednesday, 3 February 2021

Why do we yawn?

Why do we yawn?


 Everybody yawns — from unborn babies to the oldest great-grandparent. Animals do it, too. But why, exactly, do people and animals yawn? No one knows for sure. But there are many theories (ideas) about why people yawn. 

One is that when we are bored or tired, we just don't breathe as deeply as we usually do. As this theory goes, our bodies take in less oxygen because our breathing has slowed. Therefore, yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood.

Yawning, then, would be an involuntary reflex (something we can't really control) to help us control our oxygen and carbon dioxide levels. Sounds good, but other studies have shown that breathing more oxygen does not decrease yawning. Likewise, breathing more carbon dioxide does not increase yawning. Hmmm. Now what?

Another theory is that yawning stretches the lungs and lung tissue. Stretching and yawning may be a way to flex muscles and joints, increase heart rate, and feel more awake.

Other people believe that yawning is a protective reflex to redistribute the oil-like substance called surfactant (say: sur-FAK-tint) that helps keep lungs lubricated inside and keeps them from collapsing. So, if we didn't yawn, according to this theory, taking a deep breath would become harder and harder — and that would not be good!

But there is one idea about yawning that everyone knows to be true. It seems contagious. If you yawn in class, you'll probably notice a few other people will start yawning, too. Even thinking about yawning can get you yawning. How many times have you yawned while reading this article? We hope not many!

Monday, 1 February 2021

Why do we dream?

 



One widely held theory about the purpose of dreams is that they help you store important memories and things you've learned, get rid of unimportant memories, and sort through complicated thoughts and feelings. Research shows that sleep helps store memories.

Dreams are hallucinations that occur during certain stages of sleep. They’re strongest during REM sleep, or the rapid eye movement stage, when you may be less likely to recall your dream. Much is known about the role of sleep in regulating our metabolism, blood pressure, brain function, and other aspects of health. But it’s been harder for researchers to explain the role of dreams.

When you’re awake, your thoughts have a certain logic to them. When you sleep, your brain is still active, but your thoughts or dreams often make little or no sense. This may be because the emotional centers of the brain trigger dreams, rather than the logical regions.

Though there’s no definitive proof, dreams are usually autobiographical thoughts based on your recent activities, conversations, or other issues in your life. However, there are some popular theories on the role of dreams.

Researchers still don’t entirely agree on the purpose of dreams. There are, however, some widely held beliefs and theories.

Dreams as therapists

Your dreams may be ways of confronting emotional dramas in your life. And because your brain is operating at a much more emotional level than when you’re awake, your brain may make connections regarding your feelings that your conscious self wouldn’t make.

Dreams as fight-or-flight training

One of the areas of the brain that’s most active during dreaming is the amygdala. The amygdala is the part of the brain associated with the survival instinct and the fight-or-flight response.

One theory suggests that because the amygdala is more active during sleep than in your waking life, it may be the brain’s way of getting you ready to deal with a threat.

Fortunately, the brainstem sends out nerve signals during REM sleep that relax your muscles. That way you don’t try to run or punch in your sleep.

Dreams as your muse

One theory for why we dream is that it helps facilitate our creative tendencies. Artists of all kinds credit dreams with inspiring some of their most creative work. You may have awakened at times in your life with a great idea for a movie or a song, too.

Without the logic filter, you might normally use in your waking life that can restrict your creative flow, your thoughts and ideas have no restrictions when you’re sleeping.

Dreams as memory aides

One widely held theory about the purpose of dreams is that they help you store important memories and things you’ve learned, get rid of unimportant memories, and sort through complicated thoughts and feelings.

Research showsTrusted Source that sleep helps store memories. If you learn new information and sleep on it, you’ll be able to recall it better than if asked to remember that information without the benefit of sleep.

How dreams affect memory storage and recall isn’t clearly understood yet. But dreams may help the brain more efficiently store important information while blocking out stimuli that could interfere with memory and learning.

The Secret of How the Titanic Sank

  The Secret of How the Titanic Sank New evidence has experts rethinking how the luxury passenger liner sank. FOR DECADES AFTER THE  disaste...