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 ictnasne, that you could only see things that were red and that everything else was cepltmoely 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 lhgit. Different kinds of light are all around you everyday but are ibnilvise to the human eye, from the raido 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 rtdaiaion that acts like both a wave and a plcritae. Light waves are kind of like waves on the ocean. There are big wveas 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 erneegis. It's easy to remember if you think about being in that boat. If you were out siianlg 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 eregny of light tells us how it will interact with mteatr, 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 rgane in energy, and so we call that range of light visible light. Inside our rintea 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 svsienite 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 amonut of energy each cone measures signals our brain to perceive colors. The rainbow we perceive is actually vbiisle 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 shrot wanltgeveh or high energy gets absorbed by the eye's sfurace 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 wehetvgnlas. 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 deerttcos that are sltieuamtd by these other wavelengths of light, kind of like dgiital 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 mnemot. 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 sercutpm 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 cayron — pretty sad. To see the uvesnire in its full spectrum, we need to have the right eyes, and that manes using special telescopes that can help us see beyond visible light. You've probably heard of the Hubble Space Telescope and seen its baituufel pictures taken in visible and ultraviolet light. But you might not know that there are 20 space tseleocpes in orbit, minsosis that can each see part of the full spectrum of light. With telescopes acting as our virtaul 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 sutdy the light of a distant star or gxlaay and know what kdins 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 natraul wrold can help you perceive the full spectrum 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 __________ 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 _____. Different kinds of light are all around you everyday but are _________ to the human eye, from the _____ 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 _________ that acts like both a wave and a ________. Light waves are kind of like waves on the ocean. There are big _____ 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 ________. It's easy to remember if you think about being in that boat. If you were out _______ 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 ______ of light tells us how it will interact with ______, 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 _____ in energy, and so we call that range of light visible light. Inside our ______ 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 _________ 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 ______ of energy each cone measures signals our brain to perceive colors. The rainbow we perceive 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 _____ __________ or high energy gets absorbed by the eye's _______ 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 ___________. 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 _________ that are __________ by these other wavelengths of light, kind of like _______ 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 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 ________ 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 ______ — pretty sad. To see the ________ in its full spectrum, we need to have the right eyes, and that _____ using special telescopes that can help us see beyond visible light. You've probably heard of the Hubble Space Telescope and seen its _________ pictures taken in visible and ultraviolet light. But you might not know that there are 20 space __________ in orbit, ________ that can each see part of the full spectrum of light. With telescopes acting as our _______ 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 _____ the light of a distant star or ______ and know what _____ 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 _______ _____ can help you perceive the full spectrum around you all the time.

Solution


  1. energies
  2. completely
  3. sensitive
  4. universe
  5. retina
  6. kinds
  7. particle
  8. range
  9. study
  10. short
  11. radiation
  12. visible
  13. moment
  14. matter
  15. energy
  16. galaxy
  17. digital
  18. surface
  19. natural
  20. sailing
  21. crayon
  22. light
  23. world
  24. virtual
  25. stimulated
  26. detectors
  27. wavelength
  28. amount
  29. telescopes
  30. wavelengths
  31. invisible
  32. beautiful
  33. instance
  34. spectrum
  35. waves
  36. means
  37. radio
  38. missions

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