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      "utf8": "Take a look out your window,"
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    "segs": [ {
      "utf8": "You might want to grab a pair of binoculars, too,"
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    "segs": [ {
      "utf8": "or a magnifying lens."
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    "segs": [ {
      "utf8": "Now, what do you see?"
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    "segs": [ {
      "utf8": "Well, whatever it is,"
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    "segs": [ {
      "utf8": "it's not the multiple layers of glass"
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    "segs": [ {
      "utf8": "right in front of you."
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    "segs": [ {
      "utf8": "But have you ever wondered"
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    "segs": [ {
      "utf8": "To understand that,"
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      "utf8": "we have to understand what glass actually is,"
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    "segs": [ {
      "utf8": "and where it comes from."
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      "utf8": "It all begins in the Earth's crust,"
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      "utf8": "where the two most common elements are"
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    "segs": [ {
      "utf8": "These react together to form silicon dioxide,"
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    "segs": [ {
      "utf8": "whose molecules arrange themselves"
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    "segs": [ {
      "utf8": "into a regular crystalline form known as quartz."
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    "segs": [ {
      "utf8": "Quartz is commonly found in sand,"
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    "segs": [ {
      "utf8": "where it often makes up most of the grains"
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      "utf8": "and is the main ingredient in most type of glass."
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    "segs": [ {
      "utf8": "Of course, you probably noticed that glass"
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      "utf8": "For one thing, the edges of the rigidly formed grains"
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      "utf8": "and smaller defects within the crystal structure"
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      "utf8": "reflect and disperse light that hits them."
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    "segs": [ {
      "utf8": "But when the quartz is heated high enough"
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      "utf8": "the extra energy makes the molecules vibrate"
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      "utf8": "until they break the bonds holding them together"
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      "utf8": "and become a flowing liquid,"
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      "utf8": "the same way that ice melts into water."
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    "segs": [ {
      "utf8": "Unlike water, though, liquid silicon dioxide"
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      "utf8": "does not reform into a crystal solid when it cools."
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      "utf8": "Instead, as the molecules lose energy,"
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      "utf8": "and the result is what is called an amorphous solid."
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      "utf8": "which allows the molecules to freely fill in any gaps."
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      "utf8": "This makes the surface of glass uniform"
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    "segs": [ {
      "utf8": "But this still doesn't explain"
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      "utf8": "rather than being absorbed as with most solids."
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    "segs": [ {
      "utf8": "For that, we need to go all the way down"
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      "utf8": "You may know that an atom consists of a nucleus"
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      "utf8": "while the electrons would be like grains of sand"
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      "utf8": "That should leave plenty of space"
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      "utf8": "The answer has to do with the different energy levels"
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      "utf8": "Think of these as different rows of seats"
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    "segs": [ {
      "utf8": "Photons from ultraviolet light, on the other hand,"
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