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  • How many times can you fold a piece of paper?

  • Assume that one had a piece of paper that was very fine,

  • like the kind they typically use to print the Bible.

  • In reality, it seems like a piece of silk.

  • To qualify these ideas,

  • let's say you have a paper that's one-thousandth of a centimeter in thickness.

  • That is 10 to the power of minus three centimeters,

  • which equals .001 centimeters.

  • Let's also assume that you have a big piece of paper,

  • like a page out of the newspaper.

  • Now we begin to fold it in half.

  • How many times do you think it could be folded like that?

  • And another question:

  • If you could fold a paper over and over, as many times as you wish,

  • say 30 times, what would you imagine the thickness of the paper would be then?

  • Before you move on,

  • I encourage you to actually think about a possible answer to this question.

  • OK. After we have folded the paper once,

  • It is now two-thousandths of a centimeter in thickness.

  • If we fold it in half once again,

  • the paper will become four-thousandths of a centimeter.

  • With every fold we make, the paper doubles in thickness.

  • And if we continue to fold it again and again,

  • always in half, we would confront the following situation

  • after 10 folds.

  • Two to the power of 10,

  • meaning that you multiply two by itself 10 times,

  • is one thousand and 24 thousandths of a centimeter,

  • which is a little bit over one centimeter.

  • Assume we continue folding the paper in half.

  • What will happen then?

  • If we fold it 17 times,

  • we'll get a thickness of two to the power of 17,

  • which is 131 centimeters,

  • and that equals just over four feet.

  • If we were able to fold it 25 times,

  • then we would get two to the power of 25,

  • which is 33, 554 centimeters,

  • just over 1,100 feet.

  • That would make it almost as tall as the Empire State Building.

  • It's worthwhile to stop here and reflect for a moment.

  • Folding a paper in half, even a paper as fine as that of the Bible,

  • 25 times would give us a paper almost a quarter of a mile.

  • What do we learn?

  • This type of growth is called exponential growth,

  • and as you see, just by folding a paper

  • we can go very far, but very fast too.

  • Summarizing, if we fold a paper

  • 25 times, the thickness is almost a quarter of a mile.

  • Thirty times, the thickness reaches 6.5 miles,

  • which is about the average height that planes fly.

  • Forty times, the thickness is nearly 7,000 miles,

  • or the average GPS satellite's orbit.

  • Forty-eight times, the thickness is way over one million miles.

  • Now, if you think that the distance between the Earth and the Moon

  • is less than 250,000 miles,

  • then starting with a piece of Bible paper

  • and folding it 45 times, we get to the Moon.

  • And if we double it one more time,

  • we get back to Earth.

  • Lesson By : Adrian Paenza narration By : Adrian Paenza Animation by : TED-ED Team

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B1 TED-Ed paper thickness fold centimeter folding

【TED-Ed】How folding paper can get you to the moon - Adrian Paenza

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    Yu Syuan Luo posted on 2013/10/16
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