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動画の字幕をクリックしてすぐ単語の意味を調べられます!
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Math wasn't made up
to harass English majors.
It was invented by a little something called, "nature,"
and it's everywhere you look.
In fact, there are specific numbers
that we see in nature all the time.
Together, they're called
"The Fibonacci Sequence"
and it goes something like this:
1, 1, 2, 3, 5, 8, 13, 21, 34, 55
You may know this pattern.
The first and second add up to the third,
and the second and the third add up to the fourth,
the fourth and the fifth add up to the sixth,
and so on.
The sequence was first described by mathematicians in India
about 1300 years ago,
and it was introduced to the west in 1202
by Leonardo of Pisa,
aka Fibonacci,
who was also responsible for introducing
Arabic numerals to Europe, which, yeah, if hadn't done that
we'd still be counting in Roman numerals
which would be
terrible.
Fibonacci was a mathematician
and in his book, Liber Abaci,
he described the sequence
with a thought experiments about a family of incestuous bunnies.
If you put one boy bunny and one girl bunny together,
that's two. And those two together will make a third,
and those three when they're done, you know, taking turns will make five. Et cetera.
But, the easiest place to find these numbers in nature isn't in bunnies.
It's in plants.
If you cut a banana into slices, you'll see it has three distinct sections;
an apple has five. No matter what kind of flower
you're looking at, chances are it has three, five, eight, thirteen, or twenty one petals.
Rows of seeds in sunflowers and pine cones always add up to Fibonacci numbers.
Our plants don't grow this way because they're receiving
some kind of mysterious, cosmic mandate.
They're doing it because it's the most efficient way
to pack as many seeds as possible into a small space,
and if you want to see why that is, you can go watch Vi Hart's video, which is linked in the description
and it's awesome.
But in addition to the numbers themselves, you also see the same ratio between Fibonacci numbers showing up.
When you divide almost any Fibonacci number by the one before it in the sequence,
especially the larger ones, you get the same number: 1.618... lots of numbers.
The Greeks discovered this long before Fibonacci, and they called it Phi.
Today, it's sometimes known as the Golden Ratio.
Phi was purportedly used by the ancient Greek sculptor Phidias to illustrate the idea of physical perfection.
He is said to have used Phi as a ratio between the statue's total height and the distance from the bottom
of its feet to its navel, for instance.
And also the length of a face divided by its width.
There's a whole other set of patterns in nature that are based on what's called the Golden Rectangle -
a rectangle whose sides lengths are successive Fibonacci numbers, like 8x13.
This rectangle can be divided up into a series of squares whose lengths are also
successive Fibonacci numbers, in this case: 1x1, 2x2, 3x3, 5x5, and 8x8.
When you draw an arc from one corner of each square to the other,
they join to form a spiral that resembles many of the spirals we observe in nature -
in the unfolding leaves of a desert succulent,
the arrangement of those pine cone lobes and sunflower seeds,
in the shells of some snails.
The math, you guys...
It can be beautiful, too.
Thanks for watching this episode of SciShow.
If you'd like to get in touch with us, leave suggestions or ideas,
we'll be in the comments below or on Facebook or Twitter,
and if you want to continue getting smarter with us, you can go to youtube.com/SciShow and subscribe.
コツ:単語をクリックしてすぐ意味を調べられます!

読み込み中…

The Fibonacci Sequence: Nature's Code

1778 タグ追加 保存
Julia Kuo 2019 年 6 月 20 日 に公開
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