full transcript

From the Ted Talk by Lucianne Walkowicz: Light waves, visible and invisible

Unscramble the Blue Letters

What if you could only see one color? Imagine, for itanncse, that you could only see things that were red and that everything else was completely invisible to you. As it turns out, that's how you live your life all the time because your eyes can only see a minuscule part of the full spectrum of light. Different kinds of lhgit are all around you everyday but are invisible to the hmaun eye, from the radio waves that carry your favorite songs, to the x-rays doctors use to see inside of you, to the mraviocwes that heat up your food. In oedrr to understand how these can all be light, we'll need to know a thing or two about what light is. Light is eocegmrlettniac radiation that acts like both a wave and a particle. Light waves are kind of like waves on the ocaen. There are big waves and small waves, waves that crash on the shore one right after the other, and waves that only roll in every so often. The size of a wave is called its wavelength, and how often it comes by is called its frequency. Imagine being a boat in that ocean, bbniobg up and down as the waves go by. If the waves that day have long wavelengths, they'll make you bob only so often, or at a low frequency. If the waves, instead, have short wavelengths, they'll be close together, and you'll bob up and down much more often, at a high frequency. Different kdnis of light are all waevs, they just have different wavelengths and frequencies. If you know the wleevangth or frequency of a wave of light, you can also fugrie out its energy. Long wavelengths have low energies, while short wgvheleants have high egrenies. It's easy to remember if you think about being in that boat. If you were out sailing on a day with short, choppy waves, you'd probably be pretty high energy yourself, running around to keep things from falling over. But on a long wavelength sea, you'd be rolling along, relaxed, low energy. The energy of light tlels us how it will interact with matter, for example, the cells of our eyes. When we see, it's because the energy of light stimulates a receptor in our eye clelad the retina. Our retina are only sensitive to light with a very small range in energy, and so we call that range of light visible light. Inside our retina are special receptors called rods and cones. The rods marsuee brtgsnehis, so we know how much light there is. The cones are in charge of what cloor of light we see because different cones are sensitive to different energies of light. Some cneos are more excited by light that is long wavelength and low energy, and other cones are more excited by short wavelength, high-energy light. When light hits our eye, the relative amount of energy each cone measures signals our brain to perceive colors. The rainbow we peirceve is actually vilbise light in order of its energy. At one side of the rainbow is low-energy light we see as red, and at the other side is high-energy light we see as blue. If light shines on us that has an energy our retina can't measure, we won't be able to see it. Light that is too short wavelength or high energy gets absorbed by the eye's surface before it can even get to the retina, and light that is too long wavelength doesn't have enough egenry to stimulate our retina at all. The only thing that makes one kind of light different from another is its wavelength. Radio waves have long wavelengths, while x-rays have short wavelengths. And visible light, the kind you can actually see, is somewhere in between. Even though our eyes can't decett light outside of the visible range, we can build special detectors that are stmaeuitld by these other wavelengths of light, kind of like digital eyes. With these devices, we can measure the light that is there, even though we can't see it ourselves. So, take a step back and think about all of this for a mnmoet. Even though they seem different, the warmth you feel from a crackling fire is the same as the sun shining on you on a btifaueul day, the same as uollvatiret light you put on sunscreen to protect yourself from, the same thing as your TV, your radio, and your microwave. Now, those examples are all things here on Earth, things you experience in your everyday life, but here's something even more amazing. Our uesivrne gives off the full spectrum of light, too. When you think of the night sky, you probably think of being able to see the srats shining with your own eyes, but that's just visible light, which you now know is only a tiny part of the full spectrum. If we had to draw the universe and could only use visible light, it would be like having only one crayon — pretty sad. To see the universe in its full spectrum, we need to have the right eyes, and that means using special telescopes that can help us see beyond visible light. You've probably haerd of the hulbbe Space Telescope and seen its beautiful pictures taken in visible and ultraviolet light. But you might not know that there are 20 space telescopes in orbit, missions that can each see part of the full spectrum of light. With telescopes acting as our virtual eyes, both in space and here on erath, we can see some amazing things. And the coolest thing of all, no matter the wavelength or energy, the light that we see out in the distant universe is the same thing as the light that we can experience and stduy here on Earth. So, since we know the physics of how x-ray, ultraviolet light, or microwaves work here, we can study the light of a dtnisat star or galaxy and know what kinds of things are happening there too. So, as you go about your daily life, think beyond what your eyes can and can't see. Knowing just a little bit about the natural world can help you perceive the full speutcrm around you all the time.

Open Cloze

What if you could only see one color? Imagine, for ________, that you could only see things that were red and that everything else was completely invisible to you. As it turns out, that's how you live your life all the time because your eyes can only see a minuscule part of the full spectrum of light. Different kinds of _____ are all around you everyday but are invisible to the _____ eye, from the radio waves that carry your favorite songs, to the x-rays doctors use to see inside of you, to the __________ that heat up your food. In _____ to understand how these can all be light, we'll need to know a thing or two about what light is. Light is _______________ radiation that acts like both a wave and a particle. Light waves are kind of like waves on the _____. There are big waves and small waves, waves that crash on the shore one right after the other, and waves that only roll in every so often. The size of a wave is called its wavelength, and how often it comes by is called its frequency. Imagine being a boat in that ocean, _______ up and down as the waves go by. If the waves that day have long wavelengths, they'll make you bob only so often, or at a low frequency. If the waves, instead, have short wavelengths, they'll be close together, and you'll bob up and down much more often, at a high frequency. Different _____ of light are all _____, they just have different wavelengths and frequencies. If you know the __________ or frequency of a wave of light, you can also ______ out its energy. Long wavelengths have low energies, while short ___________ have high ________. It's easy to remember if you think about being in that boat. If you were out sailing on a day with short, choppy waves, you'd probably be pretty high energy yourself, running around to keep things from falling over. But on a long wavelength sea, you'd be rolling along, relaxed, low energy. The energy of light _____ us how it will interact with matter, for example, the cells of our eyes. When we see, it's because the energy of light stimulates a receptor in our eye ______ the retina. Our retina are only sensitive to light with a very small range in energy, and so we call that range of light visible light. Inside our retina are special receptors called rods and cones. The rods _______ __________, so we know how much light there is. The cones are in charge of what _____ of light we see because different cones are sensitive to different energies of light. Some _____ are more excited by light that is long wavelength and low energy, and other cones are more excited by short wavelength, high-energy light. When light hits our eye, the relative amount of energy each cone measures signals our brain to perceive colors. The rainbow we ________ is actually _______ light in order of its energy. At one side of the rainbow is low-energy light we see as red, and at the other side is high-energy light we see as blue. If light shines on us that has an energy our retina can't measure, we won't be able to see it. Light that is too short wavelength or high energy gets absorbed by the eye's surface before it can even get to the retina, and light that is too long wavelength doesn't have enough ______ to stimulate our retina at all. The only thing that makes one kind of light different from another is its wavelength. Radio waves have long wavelengths, while x-rays have short wavelengths. And visible light, the kind you can actually see, is somewhere in between. Even though our eyes can't ______ light outside of the visible range, we can build special detectors that are __________ by these other wavelengths of light, kind of like digital eyes. With these devices, we can measure the light that is there, even though we can't see it ourselves. So, take a step back and think about all of this for a ______. Even though they seem different, the warmth you feel from a crackling fire is the same as the sun shining on you on a _________ day, the same as ___________ light you put on sunscreen to protect yourself from, the same thing as your TV, your radio, and your microwave. Now, those examples are all things here on Earth, things you experience in your everyday life, but here's something even more amazing. Our ________ gives off the full spectrum of light, too. When you think of the night sky, you probably think of being able to see the _____ shining with your own eyes, but that's just visible light, which you now know is only a tiny part of the full spectrum. If we had to draw the universe and could only use visible light, it would be like having only one crayon — pretty sad. To see the universe in its full spectrum, we need to have the right eyes, and that means using special telescopes that can help us see beyond visible light. You've probably _____ of the ______ Space Telescope and seen its beautiful pictures taken in visible and ultraviolet light. But you might not know that there are 20 space telescopes in orbit, missions that can each see part of the full spectrum of light. With telescopes acting as our virtual eyes, both in space and here on _____, we can see some amazing things. And the coolest thing of all, no matter the wavelength or energy, the light that we see out in the distant universe is the same thing as the light that we can experience and _____ here on Earth. So, since we know the physics of how x-ray, ultraviolet light, or microwaves work here, we can study the light of a _______ star or galaxy and know what kinds of things are happening there too. So, as you go about your daily life, think beyond what your eyes can and can't see. Knowing just a little bit about the natural world can help you perceive the full ________ around you all the time.

Solution

  1. figure
  2. detect
  3. measure
  4. cones
  5. bobbing
  6. visible
  7. microwaves
  8. ultraviolet
  9. stars
  10. beautiful
  11. kinds
  12. light
  13. energy
  14. universe
  15. wavelength
  16. color
  17. electromagnetic
  18. human
  19. perceive
  20. spectrum
  21. instance
  22. study
  23. waves
  24. order
  25. distant
  26. brightness
  27. wavelengths
  28. called
  29. tells
  30. stimulated
  31. earth
  32. heard
  33. hubble
  34. ocean
  35. energies
  36. moment

Original Text

What if you could only see one color? Imagine, for instance, that you could only see things that were red and that everything else was completely invisible to you. As it turns out, that's how you live your life all the time because your eyes can only see a minuscule part of the full spectrum of light. Different kinds of light are all around you everyday but are invisible to the human eye, from the radio waves that carry your favorite songs, to the x-rays doctors use to see inside of you, to the microwaves that heat up your food. In order to understand how these can all be light, we'll need to know a thing or two about what light is. Light is electromagnetic radiation that acts like both a wave and a particle. Light waves are kind of like waves on the ocean. There are big waves and small waves, waves that crash on the shore one right after the other, and waves that only roll in every so often. The size of a wave is called its wavelength, and how often it comes by is called its frequency. Imagine being a boat in that ocean, bobbing up and down as the waves go by. If the waves that day have long wavelengths, they'll make you bob only so often, or at a low frequency. If the waves, instead, have short wavelengths, they'll be close together, and you'll bob up and down much more often, at a high frequency. Different kinds of light are all waves, they just have different wavelengths and frequencies. If you know the wavelength or frequency of a wave of light, you can also figure out its energy. Long wavelengths have low energies, while short wavelengths have high energies. It's easy to remember if you think about being in that boat. If you were out sailing on a day with short, choppy waves, you'd probably be pretty high energy yourself, running around to keep things from falling over. But on a long wavelength sea, you'd be rolling along, relaxed, low energy. The energy of light tells us how it will interact with matter, for example, the cells of our eyes. When we see, it's because the energy of light stimulates a receptor in our eye called the retina. Our retina are only sensitive to light with a very small range in energy, and so we call that range of light visible light. Inside our retina are special receptors called rods and cones. The rods measure brightness, so we know how much light there is. The cones are in charge of what color of light we see because different cones are sensitive to different energies of light. Some cones are more excited by light that is long wavelength and low energy, and other cones are more excited by short wavelength, high-energy light. When light hits our eye, the relative amount of energy each cone measures signals our brain to perceive colors. The rainbow we perceive is actually visible light in order of its energy. At one side of the rainbow is low-energy light we see as red, and at the other side is high-energy light we see as blue. If light shines on us that has an energy our retina can't measure, we won't be able to see it. Light that is too short wavelength or high energy gets absorbed by the eye's surface before it can even get to the retina, and light that is too long wavelength doesn't have enough energy to stimulate our retina at all. The only thing that makes one kind of light different from another is its wavelength. Radio waves have long wavelengths, while x-rays have short wavelengths. And visible light, the kind you can actually see, is somewhere in between. Even though our eyes can't detect light outside of the visible range, we can build special detectors that are stimulated by these other wavelengths of light, kind of like digital eyes. With these devices, we can measure the light that is there, even though we can't see it ourselves. So, take a step back and think about all of this for a moment. Even though they seem different, the warmth you feel from a crackling fire is the same as the sun shining on you on a beautiful day, the same as ultraviolet light you put on sunscreen to protect yourself from, the same thing as your TV, your radio, and your microwave. Now, those examples are all things here on Earth, things you experience in your everyday life, but here's something even more amazing. Our universe gives off the full spectrum of light, too. When you think of the night sky, you probably think of being able to see the stars shining with your own eyes, but that's just visible light, which you now know is only a tiny part of the full spectrum. If we had to draw the universe and could only use visible light, it would be like having only one crayon — pretty sad. To see the universe in its full spectrum, we need to have the right eyes, and that means using special telescopes that can help us see beyond visible light. You've probably heard of the Hubble Space Telescope and seen its beautiful pictures taken in visible and ultraviolet light. But you might not know that there are 20 space telescopes in orbit, missions that can each see part of the full spectrum of light. With telescopes acting as our virtual eyes, both in space and here on Earth, we can see some amazing things. And the coolest thing of all, no matter the wavelength or energy, the light that we see out in the distant universe is the same thing as the light that we can experience and study here on Earth. So, since we know the physics of how x-ray, ultraviolet light, or microwaves work here, we can study the light of a distant star or galaxy and know what kinds of things are happening there too. So, as you go about your daily life, think beyond what your eyes can and can't see. Knowing just a little bit about the natural world can help you perceive the full spectrum around you all the time.

Frequently Occurring Word Combinations

ngrams of length 2

collocation frequency
full spectrum 5
long wavelength 3
visible light 3
radio waves 2
short wavelengths 2
high energy 2
ultraviolet light 2

Important Words

  1. absorbed
  2. acting
  3. acts
  4. amazing
  5. amount
  6. beautiful
  7. big
  8. bit
  9. blue
  10. boat
  11. bob
  12. bobbing
  13. brain
  14. brightness
  15. build
  16. call
  17. called
  18. carry
  19. cells
  20. charge
  21. choppy
  22. close
  23. color
  24. colors
  25. completely
  26. cone
  27. cones
  28. coolest
  29. crackling
  30. crash
  31. crayon
  32. daily
  33. day
  34. detect
  35. detectors
  36. devices
  37. digital
  38. distant
  39. doctors
  40. draw
  41. earth
  42. easy
  43. electromagnetic
  44. energies
  45. energy
  46. everyday
  47. examples
  48. excited
  49. experience
  50. eye
  51. eyes
  52. falling
  53. favorite
  54. feel
  55. figure
  56. fire
  57. food
  58. frequencies
  59. frequency
  60. full
  61. galaxy
  62. happening
  63. heard
  64. heat
  65. high
  66. hits
  67. hubble
  68. human
  69. imagine
  70. instance
  71. interact
  72. invisible
  73. kind
  74. kinds
  75. knowing
  76. life
  77. light
  78. live
  79. long
  80. matter
  81. means
  82. measure
  83. measures
  84. microwave
  85. microwaves
  86. minuscule
  87. missions
  88. moment
  89. natural
  90. night
  91. ocean
  92. orbit
  93. order
  94. part
  95. particle
  96. perceive
  97. physics
  98. pictures
  99. pretty
  100. protect
  101. put
  102. radiation
  103. radio
  104. rainbow
  105. range
  106. receptor
  107. receptors
  108. red
  109. relative
  110. relaxed
  111. remember
  112. retina
  113. rods
  114. roll
  115. rolling
  116. running
  117. sad
  118. sailing
  119. sea
  120. sensitive
  121. shines
  122. shining
  123. shore
  124. short
  125. side
  126. signals
  127. size
  128. sky
  129. small
  130. songs
  131. space
  132. special
  133. spectrum
  134. star
  135. stars
  136. step
  137. stimulate
  138. stimulated
  139. stimulates
  140. study
  141. sun
  142. sunscreen
  143. surface
  144. telescope
  145. telescopes
  146. tells
  147. time
  148. tiny
  149. turns
  150. tv
  151. ultraviolet
  152. understand
  153. universe
  154. virtual
  155. visible
  156. warmth
  157. wave
  158. wavelength
  159. wavelengths
  160. waves
  161. work
  162. world