TedTest

From the Ted Talk by Katerina Kaouri: The sonic boom problem

Unscramble the Blue Letters

Humans have been fascinated with seped for ages. The htrsoiy of human progress is one of ever-increasing velocity, and one of the most important avihentecems in this hirtisocal race was the breaking of the sound barrier. Not long after the first successful aniarple flights, pilots were eager to push their planes to go faster and ftaesr. But as they did so, increased telubnurce and large forces on the plane prevented them from accelerating further. Some tried to circumvent the pblroem through rskiy dives, often with tagirc results. Finally, in 1947, design improvements, such as a movable horizontal stabilizer, the all-moving tail, allowed an American military pilot named Chuck yeegar to fly the Bell X-1 aircraft at 1127 km/h, becoming the first person to break the sound barrier and travel faster than the speed of sound. The Bell X-1 was the first of many supersonic aircraft to floolw, with later designs reaching speeds over Mach 3. Aircraft tlnvraieg at spuironsec speed create a shock wave with a thunder-like noise known as a sonic boom, which can cause distress to people and amnials below or even damage buildings. For this reason, scientists around the world have been looking at sonic booms, trying to predict their path in the aehtrmspoe, where they will land, and how loud they will be. To better understand how scientists study sonic booms, let's strat with some basics of sound. iagmine throwing a small stone in a still pond. What do you see? The stone causes waves to travel in the water at the same speed in every direction. These circles that keep growing in radius are called wave fronts. srlmlaiiy, even though we cannot see it, a sianrtaoty sound source, like a home stereo, creates sound waves traveling outward. The speed of the waves depends on factors like the altitude and temperature of the air they move through. At sea lveel, sound tervlas at about 1225 km/h. But instead of circles on a two-dimensional surface, the wave fronts are now concentric serheps, with the sound traveling along rays perpendicular to these waevs. Now imagine a moving sound srouce, such as a train whistle. As the source keeps moving in a certain direction, the successive waves in front of it will become bunched closer together. This greater wave frequency is the cause of the famous dleppor effect, where approaching objects sound higher pitched. But as long as the source is moving slower than the sound waves themselves, they will remian nested within each other. It's when an object goes supersonic, moivng faster than the sound it makes, that the picture changes dramatically. As it overtakes sound waves it has eeitmtd, while generating new ones from its current position, the waves are focred together, forming a Mach cone. No sound is heard as it approaches an observer because the object is traveling faster than the sound it poudcers. Only after the object has passed will the observer hear the sonic boom. Where the Mach cone meets the gnruod, it forms a hyperbola, leaving a trail known as the boom carpet as it travels forward. This makes it possible to determine the area affected by a sonic boom. What about figuring out how snortg a sonic boom will be? This iolevnvs solving the fauoms Navier-Stokes eantoqius to find the variation of pressure in the air due to the supersonic aircraft flying through it. This results in the pressure signature known as the N-wave. What does this shape mean? Well, the sonic boom occurs when there is a sudden change in pressure, and the N-wave involves two booms: one for the iiatnil psreruse rise at the aircraft's nose, and another for when the tail passes, and the pressure suddenly runrtes to normal. This causes a dluboe boom, but it is usually herad as a slinge boom by human ears. In practice, computer models using these principles can often predict the location and itisetnny of sonic booms for given atmospheric conditions and flight trajectories, and there is ongoing research to mitigate their effects. In the meantime, supersonic flight over land rnmieas prohibited. So, are sonic bmoos a recent creation? Not exactly. While we try to find ways to silence them, a few other animals have been using sonic booms to their advantage. The giintgac Diplodocus may have been capable of cnaikcrg its tail faster than sound, at over 1200 km/h, possibly to deter predators. Some teyps of simhrp can also create a similar shock wave underwater, stnniung or even killing pray at a distance with just a snap of their oversized claw. So while we humans have made great progress in our relentless pursuit of speed, it turns out that nature was there first.

Open Cloze

Humans have been fascinated with _____ for ages. The _______ of human progress is one of ever-increasing velocity, and one of the most important ____________ in this __________ race was the breaking of the sound barrier. Not long after the first successful ________ flights, pilots were eager to push their planes to go faster and ______. But as they did so, increased __________ and large forces on the plane prevented them from accelerating further. Some tried to circumvent the _______ through _____ dives, often with ______ results. Finally, in 1947, design improvements, such as a movable horizontal stabilizer, the all-moving tail, allowed an American military pilot named Chuck ______ to fly the Bell X-1 aircraft at 1127 km/h, becoming the first person to break the sound barrier and travel faster than the speed of sound. The Bell X-1 was the first of many supersonic aircraft to ______, with later designs reaching speeds over Mach 3. Aircraft _________ at __________ speed create a shock wave with a thunder-like noise known as a sonic boom, which can cause distress to people and _______ below or even damage buildings. For this reason, scientists around the world have been looking at sonic booms, trying to predict their path in the __________, where they will land, and how loud they will be. To better understand how scientists study sonic booms, let's _____ with some basics of sound. _______ throwing a small stone in a still pond. What do you see? The stone causes waves to travel in the water at the same speed in every direction. These circles that keep growing in radius are called wave fronts. _________, even though we cannot see it, a __________ sound source, like a home stereo, creates sound waves traveling outward. The speed of the waves depends on factors like the altitude and temperature of the air they move through. At sea _____, sound _______ at about 1225 km/h. But instead of circles on a two-dimensional surface, the wave fronts are now concentric _______, with the sound traveling along rays perpendicular to these _____. Now imagine a moving sound ______, such as a train whistle. As the source keeps moving in a certain direction, the successive waves in front of it will become bunched closer together. This greater wave frequency is the cause of the famous _______ effect, where approaching objects sound higher pitched. But as long as the source is moving slower than the sound waves themselves, they will ______ nested within each other. It's when an object goes supersonic, ______ faster than the sound it makes, that the picture changes dramatically. As it overtakes sound waves it has _______, while generating new ones from its current position, the waves are ______ together, forming a Mach cone. No sound is heard as it approaches an observer because the object is traveling faster than the sound it ________. Only after the object has passed will the observer hear the sonic boom. Where the Mach cone meets the ______, it forms a hyperbola, leaving a trail known as the boom carpet as it travels forward. This makes it possible to determine the area affected by a sonic boom. What about figuring out how ______ a sonic boom will be? This ________ solving the ______ Navier-Stokes _________ to find the variation of pressure in the air due to the supersonic aircraft flying through it. This results in the pressure signature known as the N-wave. What does this shape mean? Well, the sonic boom occurs when there is a sudden change in pressure, and the N-wave involves two booms: one for the _______ ________ rise at the aircraft's nose, and another for when the tail passes, and the pressure suddenly _______ to normal. This causes a ______ boom, but it is usually _____ as a ______ boom by human ears. In practice, computer models using these principles can often predict the location and _________ of sonic booms for given atmospheric conditions and flight trajectories, and there is ongoing research to mitigate their effects. In the meantime, supersonic flight over land _______ prohibited. So, are sonic _____ a recent creation? Not exactly. While we try to find ways to silence them, a few other animals have been using sonic booms to their advantage. The ________ Diplodocus may have been capable of ________ its tail faster than sound, at over 1200 km/h, possibly to deter predators. Some _____ of ______ can also create a similar shock wave underwater, ________ or even killing pray at a distance with just a snap of their oversized claw. So while we humans have made great progress in our relentless pursuit of speed, it turns out that nature was there first.

Solution

travels
types
risky
famous
speed
shrimp
booms
stationary
involves
remains
produces
achievements
problem
remain
emitted
follow
initial
similarly
forced
double
spheres
atmosphere
airplane
single
doppler
intensity
pressure
faster
yeager
source
animals
historical
gigantic
equations
level
heard
cracking
start
strong
ground
supersonic
traveling
returns
waves
moving
tragic
turbulence
imagine
stunning
history

Original Text

Humans have been fascinated with speed for ages. The history of human progress is one of ever-increasing velocity, and one of the most important achievements in this historical race was the breaking of the sound barrier. Not long after the first successful airplane flights, pilots were eager to push their planes to go faster and faster. But as they did so, increased turbulence and large forces on the plane prevented them from accelerating further. Some tried to circumvent the problem through risky dives, often with tragic results. Finally, in 1947, design improvements, such as a movable horizontal stabilizer, the all-moving tail, allowed an American military pilot named Chuck Yeager to fly the Bell X-1 aircraft at 1127 km/h, becoming the first person to break the sound barrier and travel faster than the speed of sound. The Bell X-1 was the first of many supersonic aircraft to follow, with later designs reaching speeds over Mach 3. Aircraft traveling at supersonic speed create a shock wave with a thunder-like noise known as a sonic boom, which can cause distress to people and animals below or even damage buildings. For this reason, scientists around the world have been looking at sonic booms, trying to predict their path in the atmosphere, where they will land, and how loud they will be. To better understand how scientists study sonic booms, let's start with some basics of sound. Imagine throwing a small stone in a still pond. What do you see? The stone causes waves to travel in the water at the same speed in every direction. These circles that keep growing in radius are called wave fronts. Similarly, even though we cannot see it, a stationary sound source, like a home stereo, creates sound waves traveling outward. The speed of the waves depends on factors like the altitude and temperature of the air they move through. At sea level, sound travels at about 1225 km/h. But instead of circles on a two-dimensional surface, the wave fronts are now concentric spheres, with the sound traveling along rays perpendicular to these waves. Now imagine a moving sound source, such as a train whistle. As the source keeps moving in a certain direction, the successive waves in front of it will become bunched closer together. This greater wave frequency is the cause of the famous Doppler effect, where approaching objects sound higher pitched. But as long as the source is moving slower than the sound waves themselves, they will remain nested within each other. It's when an object goes supersonic, moving faster than the sound it makes, that the picture changes dramatically. As it overtakes sound waves it has emitted, while generating new ones from its current position, the waves are forced together, forming a Mach cone. No sound is heard as it approaches an observer because the object is traveling faster than the sound it produces. Only after the object has passed will the observer hear the sonic boom. Where the Mach cone meets the ground, it forms a hyperbola, leaving a trail known as the boom carpet as it travels forward. This makes it possible to determine the area affected by a sonic boom. What about figuring out how strong a sonic boom will be? This involves solving the famous Navier-Stokes equations to find the variation of pressure in the air due to the supersonic aircraft flying through it. This results in the pressure signature known as the N-wave. What does this shape mean? Well, the sonic boom occurs when there is a sudden change in pressure, and the N-wave involves two booms: one for the initial pressure rise at the aircraft's nose, and another for when the tail passes, and the pressure suddenly returns to normal. This causes a double boom, but it is usually heard as a single boom by human ears. In practice, computer models using these principles can often predict the location and intensity of sonic booms for given atmospheric conditions and flight trajectories, and there is ongoing research to mitigate their effects. In the meantime, supersonic flight over land remains prohibited. So, are sonic booms a recent creation? Not exactly. While we try to find ways to silence them, a few other animals have been using sonic booms to their advantage. The gigantic Diplodocus may have been capable of cracking its tail faster than sound, at over 1200 km/h, possibly to deter predators. Some types of shrimp can also create a similar shock wave underwater, stunning or even killing pray at a distance with just a snap of their oversized claw. So while we humans have made great progress in our relentless pursuit of speed, it turns out that nature was there first.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
sonic boom	4
sound waves	3
sonic booms	3
sound barrier	2
supersonic aircraft	2
shock wave	2
wave fronts	2
mach cone	2

Important Words

accelerating
achievements
advantage
affected
ages
air
aircraft
airplane
allowed
altitude
american
animals
approaches
approaching
area
atmosphere
atmospheric
barrier
basics
bell
boom
booms
break
breaking
buildings
bunched
called
capable
carpet
change
chuck
circles
circumvent
claw
closer
computer
concentric
conditions
cone
cracking
create
creates
creation
current
damage
depends
design
designs
deter
determine
diplodocus
direction
distance
distress
dives
doppler
double
dramatically
due
eager
ears
effect
effects
emitted
equations
factors
famous
fascinated
faster
figuring
finally
find
flight
flights
fly
flying
follow
forced
forces
forming
forms
frequency
front
fronts
generating
gigantic
great
greater
ground
growing
hear
heard
higher
historical
history
home
horizontal
human
humans
hyperbola
imagine
important
improvements
increased
initial
intensity
involves
killing
land
large
leaving
level
location
long
loud
mach
meets
military
mitigate
models
movable
move
moving
named
nature
nested
noise
normal
nose
object
objects
observer
occurs
ongoing
outward
oversized
overtakes
passed
passes
path
people
perpendicular
person
picture
pilot
pilots
pitched
plane
planes
pond
position
possibly
practice
pray
predators
predict
pressure
prevented
principles
problem
produces
progress
prohibited
pursuit
push
race
radius
rays
reaching
reason
relentless
remain
remains
research
results
returns
rise
risky
scientists
sea
shape
shock
shrimp
signature
silence
similar
similarly
single
slower
small
snap
solving
sonic
sound
source
speed
speeds
spheres
stabilizer
start
stationary
stereo
stone
strong
study
stunning
successful
successive
sudden
suddenly
supersonic
surface
tail
temperature
throwing
tragic
trail
train
trajectories
travel
traveling
travels
turbulence
turns
types
understand
underwater
variation
velocity
water
wave
waves
ways
whistle
world
yeager