full transcript

## Unscramble the Blue Letters

The next time you see a news report of a hurricane or a tpacoirl srotm showing high winds battering trees and houses, ask yourself, "How did the wind get going so fast?" anlzmigay enough, this is a motion that started more than five billion years ago. But, to understand why, we need to understand spin. In physics, we talk about two types of miootn. The first is straight-line motion. You push on something, and it moves forward. The second type, spin, involves an object raittnog, or trniung on its axis in place. An oejcbt in straight-line motion will move forever unless something, like the friction of the ground beneath it, causes it to slow down and stop. The same thing happens when you get something sninpnig. It will keep on spinning until something stops it. But the spin can speed up. If an ice skater is gliding across the ice in straight-line motion and she pulls her arms in, she keeps on gliding at the same speed. But if she is spinning on the ice and she pulls her arms in, you know what happens next. She spins faster. This is called the conservation of angular momentum. Mathematically, angular mtenuomm is a pdcuort of two numbers, one that gives the spin rate and one that gives the distance of the mass from the axis. If something is frleey spinning, as one nmbuer gets bigger, the other gets smaller. Arms closer, spin faster. Arms farther, spin slower. Spin causes other effects, too. If you are riding on a spinning merry-go-round and you toss a ball to a friend, it will appear to follow a cvnuirg path. It doesn't actually curve, though. It really goes in a straight line. You were the one who was following a curving path, but, from your point of view, the ball appears to curve. We call this the coriolis effect. Oh, and you are riding on a speeding merry-go-round right now at this very moment. We call it the Earth. The Earth spins on its axis once each day. But why does the Earth spin? Now, that's a story that starts billions of years ago. A cloud of dust and gas that form the Sun and the ertah and the planets and you and me started to collapse as gravity pluled it all together. Before it sarettd to cplasole, this cloud had a very gentle spin. And, as it callspeod, like that ice skater pulling her arms in, the spin got faster and faster. And everything that foermd out of the cloud, the Sun and the planets around the Sun and the moons around the planets, all inherited this spin. And this inherited spin is what gives us nghit and day. And this day-night cycle is what drives our weather. The Earth is warm on the daytime side, cool on the nighttime side, and it's waemrr at the equator than at the poles. The dfncefieres in temperature make differences in air pressure, and the differences in air pressure make air move. They make the wind blow. But, because the Earth spins, the moving air curves to the right in the Northern Hemisphere because of the coriolis efceft. If there's a reiogn of low pressure in the atmosphere, air is pushed toward it, like water going down a drain. But the air cruevs to the right as it goes, and this gives it a spin. With the datimarc low pessrure in a storm, the air gets pulled in thgeitr and tighter, so it gets going faster and faster, and this is how we get the high winds of a hurricane. So, when you see a spinning storm on a wtehaer reropt, think about this: The spin ualtiletmy came from the spin of the Earth, and the Earth's spin is a remnant, a fossil relic, of the gntele spin of the cloud of dust and gas that collapsed to make the Earth some five billion years ago. You are watching something, the spin, that is older than dirt, that's older than rckos, that's older than the Earth itself.

## Open Cloze

The next time you see a news report of a hurricane or a ________ _____ showing high winds battering trees and houses, ask yourself, "How did the wind get going so fast?" _________ enough, this is a motion that started more than five billion years ago. But, to understand why, we need to understand spin. In physics, we talk about two types of ______. The first is straight-line motion. You push on something, and it moves forward. The second type, spin, involves an object ________, or _______ on its axis in place. An ______ in straight-line motion will move forever unless something, like the friction of the ground beneath it, causes it to slow down and stop. The same thing happens when you get something ________. It will keep on spinning until something stops it. But the spin can speed up. If an ice skater is gliding across the ice in straight-line motion and she pulls her arms in, she keeps on gliding at the same speed. But if she is spinning on the ice and she pulls her arms in, you know what happens next. She spins faster. This is called the conservation of angular momentum. Mathematically, angular ________ is a _______ of two numbers, one that gives the spin rate and one that gives the distance of the mass from the axis. If something is ______ spinning, as one ______ gets bigger, the other gets smaller. Arms closer, spin faster. Arms farther, spin slower. Spin causes other effects, too. If you are riding on a spinning merry-go-round and you toss a ball to a friend, it will appear to follow a _______ path. It doesn't actually curve, though. It really goes in a straight line. You were the one who was following a curving path, but, from your point of view, the ball appears to curve. We call this the coriolis effect. Oh, and you are riding on a speeding merry-go-round right now at this very moment. We call it the Earth. The Earth spins on its axis once each day. But why does the Earth spin? Now, that's a story that starts billions of years ago. A cloud of dust and gas that form the Sun and the _____ and the planets and you and me started to collapse as gravity ______ it all together. Before it _______ to ________, this cloud had a very gentle spin. And, as it _________, like that ice skater pulling her arms in, the spin got faster and faster. And everything that ______ out of the cloud, the Sun and the planets around the Sun and the moons around the planets, all inherited this spin. And this inherited spin is what gives us _____ and day. And this day-night cycle is what drives our weather. The Earth is warm on the daytime side, cool on the nighttime side, and it's ______ at the equator than at the poles. The ___________ in temperature make differences in air pressure, and the differences in air pressure make air move. They make the wind blow. But, because the Earth spins, the moving air curves to the right in the Northern Hemisphere because of the coriolis ______. If there's a ______ of low pressure in the atmosphere, air is pushed toward it, like water going down a drain. But the air ______ to the right as it goes, and this gives it a spin. With the ________ low ________ in a storm, the air gets pulled in _______ and tighter, so it gets going faster and faster, and this is how we get the high winds of a hurricane. So, when you see a spinning storm on a _______ ______, think about this: The spin __________ came from the spin of the Earth, and the Earth's spin is a remnant, a fossil relic, of the ______ spin of the cloud of dust and gas that collapsed to make the Earth some five billion years ago. You are watching something, the spin, that is older than dirt, that's older than _____, that's older than the Earth itself.

## Solution

1. number
2. earth
3. night
4. freely
5. report
6. rotating
7. weather
8. turning
9. collapse
10. region
11. spinning
12. rocks
13. gentle
14. tighter
15. dramatic
16. ultimately
17. amazingly
18. started
19. motion
20. tropical
21. product
22. pressure
23. curving
24. formed
25. storm
26. effect
27. pulled
28. momentum
29. object
30. differences
31. warmer
32. curves
33. collapsed

## Original Text

The next time you see a news report of a hurricane or a tropical storm showing high winds battering trees and houses, ask yourself, "How did the wind get going so fast?" Amazingly enough, this is a motion that started more than five billion years ago. But, to understand why, we need to understand spin. In physics, we talk about two types of motion. The first is straight-line motion. You push on something, and it moves forward. The second type, spin, involves an object rotating, or turning on its axis in place. An object in straight-line motion will move forever unless something, like the friction of the ground beneath it, causes it to slow down and stop. The same thing happens when you get something spinning. It will keep on spinning until something stops it. But the spin can speed up. If an ice skater is gliding across the ice in straight-line motion and she pulls her arms in, she keeps on gliding at the same speed. But if she is spinning on the ice and she pulls her arms in, you know what happens next. She spins faster. This is called the conservation of angular momentum. Mathematically, angular momentum is a product of two numbers, one that gives the spin rate and one that gives the distance of the mass from the axis. If something is freely spinning, as one number gets bigger, the other gets smaller. Arms closer, spin faster. Arms farther, spin slower. Spin causes other effects, too. If you are riding on a spinning merry-go-round and you toss a ball to a friend, it will appear to follow a curving path. It doesn't actually curve, though. It really goes in a straight line. You were the one who was following a curving path, but, from your point of view, the ball appears to curve. We call this the coriolis effect. Oh, and you are riding on a speeding merry-go-round right now at this very moment. We call it the Earth. The Earth spins on its axis once each day. But why does the Earth spin? Now, that's a story that starts billions of years ago. A cloud of dust and gas that form the Sun and the Earth and the planets and you and me started to collapse as gravity pulled it all together. Before it started to collapse, this cloud had a very gentle spin. And, as it collapsed, like that ice skater pulling her arms in, the spin got faster and faster. And everything that formed out of the cloud, the Sun and the planets around the Sun and the moons around the planets, all inherited this spin. And this inherited spin is what gives us night and day. And this day-night cycle is what drives our weather. The Earth is warm on the daytime side, cool on the nighttime side, and it's warmer at the equator than at the poles. The differences in temperature make differences in air pressure, and the differences in air pressure make air move. They make the wind blow. But, because the Earth spins, the moving air curves to the right in the Northern Hemisphere because of the coriolis effect. If there's a region of low pressure in the atmosphere, air is pushed toward it, like water going down a drain. But the air curves to the right as it goes, and this gives it a spin. With the dramatic low pressure in a storm, the air gets pulled in tighter and tighter, so it gets going faster and faster, and this is how we get the high winds of a hurricane. So, when you see a spinning storm on a weather report, think about this: The spin ultimately came from the spin of the Earth, and the Earth's spin is a remnant, a fossil relic, of the gentle spin of the cloud of dust and gas that collapsed to make the Earth some five billion years ago. You are watching something, the spin, that is older than dirt, that's older than rocks, that's older than the Earth itself.

## Frequently Occurring Word Combinations

### ngrams of length 2

collocation frequency
high winds 2
billion years 2
ice skater 2
angular momentum 2
coriolis effect 2
gentle spin 2
air curves 2

## Important Words

1. air
2. amazingly
3. angular
4. appears
5. arms
6. atmosphere
7. axis
8. ball
9. battering
10. beneath
11. bigger
12. billion
13. billions
14. blow
15. call
16. called
17. closer
18. cloud
19. collapse
20. collapsed
21. conservation
22. cool
23. coriolis
24. curve
25. curves
26. curving
27. cycle
28. day
29. daytime
30. differences
31. dirt
32. distance
33. drain
34. dramatic
35. drives
36. dust
37. earth
38. effect
39. effects
40. equator
41. fast
42. faster
43. follow
44. form
45. formed
46. fossil
47. freely
48. friction
49. friend
50. gas
51. gentle
52. gliding
53. gravity
54. ground
55. hemisphere
56. high
57. houses
58. hurricane
59. ice
60. inherited
61. involves
62. line
63. mass
64. mathematically
65. moment
66. momentum
67. moons
68. motion
69. move
70. moves
71. moving
72. news
73. night
74. nighttime
75. northern
76. number
77. numbers
78. object
79. older
80. path
81. physics
82. place
83. planets
84. point
85. poles
86. pressure
87. product
88. pulled
89. pulling
90. pulls
91. push
92. pushed
93. rate
94. region
95. relic
96. remnant
97. report
98. riding
99. rocks
100. rotating
101. showing
102. side
103. skater
104. slow
105. slower
106. smaller
107. speed
108. speeding
109. spin
110. spinning
111. spins
112. started
113. starts
114. stop
115. stops
116. storm
117. story
118. straight
119. sun
120. talk
121. temperature
122. tighter
123. time
124. toss
125. trees
126. tropical
127. turning
128. type
129. types
130. ultimately
131. understand
132. view
133. warm
134. warmer
135. watching
136. water
137. weather
138. wind
139. winds
140. years