TedTest

From the Ted Talk by Alex Gendler: How tsunamis work

Unscramble the Blue Letters

In 479 BC, when Persian soldiers besieged the Greek city of Potidaea, the tide retreated much farther than usual, leaving a cnnneoveit ivanison rotue. But this wasn't a stroke of luck. Before they had croessd halfway, the water returned in a wave higher than anyone had ever seen, drowning the attackers. The Potiidaeans believed they had been saved by the wrath of Poseidon. But what really saved them was likely the same phenomenon that has destroyed countless others: a tsunami. Although tsunamis are commonly known as tidal waves, they're actually unrelated to the tiadl activity caused by the gravitational forces of the Sun and Moon. In many ways, tsunamis are just larger versions of raugelr waves. They have a trough and a crest, and consist not of mvoing water, but the movement of energy through water. The difference is in where this energy comes from. For normal ocean waves, it comes from wind. Because this only affects the surface, the waves are limited in size and speed. But tmaisnus are caused by energy originating underwater, from a voinlacc eruption, a submarine landslide, or most commonly, an earthquake on the ocean floor caused when the tectonic plates of the Earth's sfcuare slip, releasing a massive amount of energy into the water. This energy travels up to the surface, diplcnaisg water and raising it above the normal sea leevl, but gravity pulls it back down, which makes the energy ripple outwards horizontally. Thus, the tsunami is born, moving at over 500 miles per hour. When it's far from shroe, a tsunami can be bleray dtacetlbee since it moves through the erntie depth of the water. But when it reaches shallow water, something called wave shoaling occurs. Because there is less wetar to move through, this still masisve amount of eegrny is compressed. The wave's speed slows down, while its height reiss to as much as 100 feet. The word tsunami, Japanese for "harbor wave," comes from the fact that it only seems to appear near the coast. If the trough of a tsunami reaches shore first, the water will withdraw farther than normal before the wave hits, which can be misleadingly dangerous. A tsunami will not only drwon people near the coast, but level buildings and trees for a mile inland or more, especially in low-lying areas. As if that weren't enough, the water then retreats, dragging with it the newly created debris, and anything, or anyone, unfortunate enough to be caught in its path. The 2004 Indian Ocean tsunami was one of the deadliest natural disasters in history, klinlig over 200,000 people throughout South Asia. So how can we protect ourselves against this destructive force of nature? People in some areas have attempted to stop tsunamis with sea walls, flood gates, and channels to divert the water. But these are not always ecfitfeve. In 2011, a tsunami surpassed the flood wall pttnirceog Japan's Fukushima Power pnalt, canuisg a nuclear dsiaster in addition to claiming over 18,000 lives. Many scientists and policy mrkeas are instead focusing on eraly dctoieten, monitoring underwater pressure and ssiimec activity, and establishing gablol communication networks for quickly distributing alerts. When nature is too powerful to stop, the safest course is to get out of its way.

Open Cloze

In 479 BC, when Persian soldiers besieged the Greek city of Potidaea, the tide retreated much farther than usual, leaving a __________ ________ _____. But this wasn't a stroke of luck. Before they had _______ halfway, the water returned in a wave higher than anyone had ever seen, drowning the attackers. The Potiidaeans believed they had been saved by the wrath of Poseidon. But what really saved them was likely the same phenomenon that has destroyed countless others: a tsunami. Although tsunamis are commonly known as tidal waves, they're actually unrelated to the _____ activity caused by the gravitational forces of the Sun and Moon. In many ways, tsunamis are just larger versions of _______ waves. They have a trough and a crest, and consist not of ______ water, but the movement of energy through water. The difference is in where this energy comes from. For normal ocean waves, it comes from wind. Because this only affects the surface, the waves are limited in size and speed. But ________ are caused by energy originating underwater, from a ________ eruption, a submarine landslide, or most commonly, an earthquake on the ocean floor caused when the tectonic plates of the Earth's _______ slip, releasing a massive amount of energy into the water. This energy travels up to the surface, __________ water and raising it above the normal sea _____, but gravity pulls it back down, which makes the energy ripple outwards horizontally. Thus, the tsunami is born, moving at over 500 miles per hour. When it's far from _____, a tsunami can be ______ __________ since it moves through the ______ depth of the water. But when it reaches shallow water, something called wave shoaling occurs. Because there is less _____ to move through, this still _______ amount of ______ is compressed. The wave's speed slows down, while its height _____ to as much as 100 feet. The word tsunami, Japanese for "harbor wave," comes from the fact that it only seems to appear near the coast. If the trough of a tsunami reaches shore first, the water will withdraw farther than normal before the wave hits, which can be misleadingly dangerous. A tsunami will not only _____ people near the coast, but level buildings and trees for a mile inland or more, especially in low-lying areas. As if that weren't enough, the water then retreats, dragging with it the newly created debris, and anything, or anyone, unfortunate enough to be caught in its path. The 2004 Indian Ocean tsunami was one of the deadliest natural disasters in history, _______ over 200,000 people throughout South Asia. So how can we protect ourselves against this destructive force of nature? People in some areas have attempted to stop tsunamis with sea walls, flood gates, and channels to divert the water. But these are not always _________. In 2011, a tsunami surpassed the flood wall __________ Japan's Fukushima Power _____, _______ a nuclear ________ in addition to claiming over 18,000 lives. Many scientists and policy ______ are instead focusing on _____ _________, monitoring underwater pressure and _______ activity, and establishing ______ communication networks for quickly distributing alerts. When nature is too powerful to stop, the safest course is to get out of its way.

Solution

barely
entire
plant
shore
rises
tidal
global
tsunamis
seismic
drown
protecting
route
convenient
detectable
crossed
early
water
massive
energy
makers
invasion
displacing
level
effective
volcanic
detection
moving
disaster
causing
regular
killing
surface

Original Text

In 479 BC, when Persian soldiers besieged the Greek city of Potidaea, the tide retreated much farther than usual, leaving a convenient invasion route. But this wasn't a stroke of luck. Before they had crossed halfway, the water returned in a wave higher than anyone had ever seen, drowning the attackers. The Potiidaeans believed they had been saved by the wrath of Poseidon. But what really saved them was likely the same phenomenon that has destroyed countless others: a tsunami. Although tsunamis are commonly known as tidal waves, they're actually unrelated to the tidal activity caused by the gravitational forces of the Sun and Moon. In many ways, tsunamis are just larger versions of regular waves. They have a trough and a crest, and consist not of moving water, but the movement of energy through water. The difference is in where this energy comes from. For normal ocean waves, it comes from wind. Because this only affects the surface, the waves are limited in size and speed. But tsunamis are caused by energy originating underwater, from a volcanic eruption, a submarine landslide, or most commonly, an earthquake on the ocean floor caused when the tectonic plates of the Earth's surface slip, releasing a massive amount of energy into the water. This energy travels up to the surface, displacing water and raising it above the normal sea level, but gravity pulls it back down, which makes the energy ripple outwards horizontally. Thus, the tsunami is born, moving at over 500 miles per hour. When it's far from shore, a tsunami can be barely detectable since it moves through the entire depth of the water. But when it reaches shallow water, something called wave shoaling occurs. Because there is less water to move through, this still massive amount of energy is compressed. The wave's speed slows down, while its height rises to as much as 100 feet. The word tsunami, Japanese for "harbor wave," comes from the fact that it only seems to appear near the coast. If the trough of a tsunami reaches shore first, the water will withdraw farther than normal before the wave hits, which can be misleadingly dangerous. A tsunami will not only drown people near the coast, but level buildings and trees for a mile inland or more, especially in low-lying areas. As if that weren't enough, the water then retreats, dragging with it the newly created debris, and anything, or anyone, unfortunate enough to be caught in its path. The 2004 Indian Ocean tsunami was one of the deadliest natural disasters in history, killing over 200,000 people throughout South Asia. So how can we protect ourselves against this destructive force of nature? People in some areas have attempted to stop tsunamis with sea walls, flood gates, and channels to divert the water. But these are not always effective. In 2011, a tsunami surpassed the flood wall protecting Japan's Fukushima Power Plant, causing a nuclear disaster in addition to claiming over 18,000 lives. Many scientists and policy makers are instead focusing on early detection, monitoring underwater pressure and seismic activity, and establishing global communication networks for quickly distributing alerts. When nature is too powerful to stop, the safest course is to get out of its way.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
massive amount	2

Important Words

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alerts
amount
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poseidon
potidaea
potiidaeans
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quickly
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shoaling
shore
size
slip
slows
soldiers
south
speed
stop
stroke
submarine
sun
surface
surpassed
tectonic
tidal
tide
travels
trees
trough
tsunami
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underwater
unfortunate
unrelated
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versions
volcanic
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walls
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withdraw
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wrath