ความคิดเห็นที่ 23
http://www.abc.net.au/science/k2/moments/s1523497.htm
Folding Paper
ตี๊ต่างกระดาษA4 30ซม.หนา0.05มม.ถ้าทบที่8ยาว1.25มม. หนา12.8มม.
หนามากกว่ายาวจึงพับไม่ได้
Suppose that you start with an standard A4 sheet of paper - about 300 mm long, and about 0.05 mm thick.
The first time you fold it in half, it becomes 150 mm long and 0.1 mm thick. The second fold takes it to 75 mm long and 0.2 mm thick. By the 8th fold (if you can get there), you have a blob of paper 1.25 mm long, but 12.8 mm thick. It's now thicker than it is long, and, if you're trying to bend it, seems to have the structural integrity of steel.
ทั่วไปจึงว่าพับครึ่งได้ไม่เกิน7ทบ
ถ้าคุณพับกระดาษ50ทบจะหนา 100 ล้านกม.
A typical claim on the Internet might run, "No matter its size or thickness, no piece of paper can be folded in half more than 7 times", and as you stare sadly at your block of folded paper, you tend to agree.
In fact, if you had a sheet of paper, and folded it in half 50 times, how thick would it be?
The answer is about 100 million kilometres, which is about two thirds of the distance between the Sun and the Earth.
คุณบริทนี่นั่นใช้แผ่นทองบางสุดๆพับได้12ทบ
That was when a high school student, Britney Gallivan (of Pomona, California) was given a maths problem. She would get an extra maths credit, if she took up the option of solving the problem of folding a sheet in half 12 times. She tried and failed with reasonably-sized sheets of paper.
So she got smart, and used something incredibly thin - gold foil, only 0.28 of millionth of a metre thick. She started with a square sheet, 10 cm by 10 cm. It took lots of determination and practice, as well as rulers, soft paint brushes and tweezers, but she finally succeeded in folding her gold foil in half 12 times. She ended up with a microscopic square sheet of gold foil.
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21 ส.ค. 50 22:31:58
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