TED-Ed
Jon Bergmann: Just how small is an atom?
Filmed:
Readability: 3.1
5,793,993 views
Just how small are atoms? Really, really, really small. This fast-paced animation from TED-Ed uses metaphors (imagine a blueberry the size of a football stadium!) to give a visceral sense of just how small atoms are. Lesson by Jon Bergmann, animation by Cognitive Media.
Jon Bergmann - Educator
Jon Bergmann co-wrote the book on the "flipped classroom" -- using video to help students master new ideas outside the traditional class setting. Full bio
Jon Bergmann co-wrote the book on the "flipped classroom" -- using video to help students master new ideas outside the traditional class setting. Full bio
Double-click the English transcript below to play the video.
00:26
You probably already know
0
13809
1200
ご存知かもしれませんが
00:28
everything is made up
of little tiny things called atoms
of little tiny things called atoms
1
15033
2690
あらゆる物質は
原子という微小なもので構成されています
原子という微小なもので構成されています
00:30
or even that each atom
is made up of even smaller particles
is made up of even smaller particles
2
17747
2961
また それぞれの原子は 陽子 中性子 電子という
00:33
called protons, neutrons and electrons.
3
20732
2122
更に小さな粒子で構成されています
00:35
And you've probably heard
that atoms are small.
that atoms are small.
4
22878
2287
原子はとても小さいです
00:38
But I bet you haven't ever thought
about how small atoms really are.
about how small atoms really are.
5
25189
4160
しかしきっと 原子がどのくらい小さいかを
考えたことは無いでしょう
考えたことは無いでしょう
00:42
Well, the answer is
that they are really, really small.
that they are really, really small.
6
29373
3716
答えを言うと とても とても 小さいです
00:46
So you ask, just how small are atoms?
7
33908
3039
原子はどのくらい小さいかって？
00:49
To understand this,
let's ask this question:
let's ask this question:
8
36971
3073
理解するために こんな質問をしてみましょう
00:53
How many atoms are in a grapefruit?
9
40068
1908
グレープフルーツ１個には何個の原子が含まれるでしょう？
00:55
Well, let's assume that the grapefruit
is made up of only nitrogen atoms,
is made up of only nitrogen atoms,
10
42721
3429
そのグレープフルーツは窒素原子のみから成ると仮定します
00:59
which isn't at all true, but there
are nitrogen atoms in a grapefruit.
are nitrogen atoms in a grapefruit.
11
46174
3658
全くそんなことはありませんが
しかしグレープフルーツには窒素原子が含まれています
しかしグレープフルーツには窒素原子が含まれています
01:02
To help you visualize this,
let's blow up each of the atoms
let's blow up each of the atoms
12
49856
3031
視覚化のために それぞれの原子を
01:05
to the size of a blueberry.
13
52911
1813
ブルーベリーの大きさまで拡大してみましょう
01:07
And then how big
would the grapefruit have to be?
would the grapefruit have to be?
14
54748
3148
するとグレープフルーツはどのくらいの
大きさになるでしょう？
大きさになるでしょう？
01:10
It would have to be the same size of
-- well, actually, the Earth.
-- well, actually, the Earth.
15
57920
4029
実のところ ほぼ地球と同じサイズにまでなるのです
01:14
That's crazy!
16
61973
1016
そんなバカな！
01:16
You mean to say that if I filled
the Earth with blueberries,
the Earth with blueberries,
17
63013
2821
地球がブルーベリーで一杯だったら
01:18
I would have the same number
of nitrogen atoms as a grapefruit?
of nitrogen atoms as a grapefruit?
18
65858
2977
同じ数の窒素原子もグレープフルーツに
あるはずだと言いたいんでしょう？
あるはずだと言いたいんでしょう？
01:21
That's right!
19
68859
1000
その通り！
01:23
So how big is the atom?
20
70258
1533
では原子はどのくらいの大きさでしょう？
01:25
Well, it's really, really small!
21
72761
1741
原子はとても とても とても とても小さいです
01:28
And you know what?
It gets even more crazy.
It gets even more crazy.
22
75541
2435
て知っそしていますか？
話はより一層バカげてくるのです
話はより一層バカげてくるのです
01:31
Let's now look inside of each atom
-- and thus the blueberry, right? --
-- and thus the blueberry, right? --
23
78000
3773
各原子 つまりブルーベリーの中を覗いてみましょう
01:34
What do you see there?
24
81797
1113
何が見えますか？
01:35
In the center of the atom
is something called the nucleus,
is something called the nucleus,
25
82934
2721
原子の中心には核と呼ばれるものがあり
01:38
which contains protons and neutrons,
26
85679
1727
陽子と中性子で構成されています
01:40
and on the outside, you'd see electrons.
27
87430
2061
そして外側には電子が見えます
01:42
So how big is the nucleus?
28
89515
1461
では核はどのくらいの大きさでしょう？
01:44
If atoms are like blueberries
in the Earth,
in the Earth,
29
91381
2135
原子が地球上でのブルーベリーなら
01:46
how big would the nucleus be?
30
93540
1777
原子核はどのくらいの大きさでしょう？
01:48
You might remember the old pictures
of the atom from science class,
of the atom from science class,
31
95341
3217
昔理科の授業で見た原子の写真に
01:51
where you saw this tiny dot on the page
with an arrow pointing to the nucleus.
with an arrow pointing to the nucleus.
32
98582
3763
小さな点が原子核を指す矢印とともに描かれているのを
思い浮かべていることでしょう
思い浮かべていることでしょう
01:55
Well, those pictures,
they're not drawn to scale,
they're not drawn to scale,
33
102369
2395
それらの図は縮尺を正確に表していないので
01:57
so they're kind of wrong.
34
104788
1615
ある意味で不正確です
01:59
So how big is the nucleus?
35
106427
1556
では原子核はどのくらいの大きさでしょう？
02:01
So if you popped open the blueberry
and were searching for the nucleus ...
and were searching for the nucleus ...
36
108007
3969
ブルーベリーの中身を取り出し
原子核を探してみても
原子核を探してみても
02:06
You know what? It would be invisible.
37
113236
2246
見ることはできません
02:08
It's too small to see!
38
115506
1642
肉眼で見るには小さすぎるのです
02:10
OK. Let's blow up the atom --
the blueberry --
the blueberry --
39
117944
2776
では原子 ここではブルーベリーを
02:13
to the size of a house.
40
120744
1232
家の大きさまで拡大してみましょう
02:15
So imagine a ball that is as tall
as a two-story house.
as a two-story house.
41
122000
3738
２階建ての家と同じくらいの高さのボールを
想像してみてください
想像してみてください
02:18
Let's look for the nucleus
in the center of the atom.
in the center of the atom.
42
125762
2477
原子の中で核を探してみましょう
02:21
And do you know what?
It would just barely be visible.
It would just barely be visible.
43
128263
3295
それでも核はほとんど見えません
02:25
So to get our minds wrapped
around how big the nucleus is,
around how big the nucleus is,
44
132141
2821
原子核がどのくらいの大きさかを理解するためには
02:27
we need to blow up the blueberry,
up to the size of a football stadium.
up to the size of a football stadium.
45
134986
3990
ブルーベリーをフットボール競技場のサイズにまで
拡大しなければなりません
拡大しなければなりません
02:32
So imagine a ball the size
of a football stadium,
of a football stadium,
46
139000
2976
フットボール競技場の大きさの
ボールを思い浮かべてください
ボールを思い浮かべてください
02:35
and right smack dab
in the center of the atom,
in the center of the atom,
47
142000
2976
ちょうど原子の真ん中で
02:38
you would find the nucleus,
and you could see it!
and you could see it!
48
145000
2334
原子核が見つかるでしょう ようやく見えたのです！
02:41
And it would be the size
of a small marble.
of a small marble.
49
148278
2624
それでも小さなビー玉程度の大きさでしかありません
02:45
And there's more, if I haven't
blown your mind by now.
blown your mind by now.
50
152121
2556
これまでに心が折れていないなら まだ話が続きます
02:47
Let's consider the atom some more.
51
154701
1620
原子についてもうちょっと考えてみましょう
02:49
It contains protons,
neutrons and electrons.
neutrons and electrons.
52
156345
2197
原子は陽子、中性子、電子を持ちます
02:51
The protons and neutrons
live inside of the nucleus,
live inside of the nucleus,
53
158566
2429
陽子と中性子は原子核内に存在し
02:54
and contain almost
all of the mass of the atom.
all of the mass of the atom.
54
161019
2191
原子の質量のほぼ全てを持ちます
02:56
Way on the edge are the electrons.
55
163234
1742
端にあるのが電子です
02:58
So if an atom is like a ball
the size of a football stadium,
the size of a football stadium,
56
165000
2976
原子がフットボール競技場の中での
ボールのようなもので
ボールのようなもので
03:01
with the nucleus in the center,
and the electrons on the edge,
and the electrons on the edge,
57
168000
2905
核が中心に 電子が端にあるとしたら
03:03
what is in between the nucleus
and the electrons?
and the electrons?
58
170929
2286
核と電子の間には何があるのでしょう？
03:07
Surprisingly, the answer is empty space.
59
174104
3007
驚くことに 答えは
空っぽの空間です
空っぽの空間です
03:10
(Wind noise)
60
177987
2570
(風の音)
03:13
That's right. Empty!
61
180581
1395
その通り 空っぽです！
03:15
Between the nucleus and the electrons,
there are vast regions of empty space.
there are vast regions of empty space.
62
182000
4305
核と電子の間にはとても広い
空っぽの空間が存在します
空っぽの空間が存在します
03:19
Now, technically there are
some electromagnetic fields,
some electromagnetic fields,
63
186329
2572
厳密には電磁場がありますが
03:21
but in terms of stuff,
matter, it is empty.
matter, it is empty.
64
188925
2911
物質という点で見ると空っぽです
03:24
Remember this vast region of empty space
is inside the blueberry,
is inside the blueberry,
65
191860
3523
気をつけなければいけないのは この広い空っぽの空間は
03:28
which is inside the Earth,
66
195407
1895
ブルーベリーの内部であり 地球の内部であること
03:30
which really are the atoms
in the grapefruit.
in the grapefruit.
67
197326
2185
つまり実際にはグレープフルーツ内の原子だということです
03:32
OK, one more thing,
if I can even get more bizarre.
if I can even get more bizarre.
68
199535
3441
ではもう１つ 更におかしなことを
03:36
Since virtually all the mass
of an atom is in the nucleus --
of an atom is in the nucleus --
69
203769
3586
原子の全質量は事実上核内に存在しているので
03:40
now, there is some amount
of mass in the electrons,
of mass in the electrons,
70
207379
2649
— 電子も微量ながら質量を持ちますが
03:43
but most of it is in the nucleus --
71
210052
2021
ほとんどの質量は核内にあります —
03:45
how dense is the nucleus?
72
212097
1772
核の密度はどれほどでしょう？
03:46
Well, the answer is crazy.
73
213893
1919
答えはとんでもないものです
03:48
The density of a typical nucleus
74
215836
1890
標準的な核の密度は
03:50
is four times 10 to the 17th
kilograms per meter cubed.
kilograms per meter cubed.
75
217750
3226
4 ×10^17 kg/m^3 です
03:54
But that's hard to visualize.
OK, I'll put it in English units.
OK, I'll put it in English units.
76
221615
3329
しかし想像するのは困難です
じゃあ英国単位に換算してみましょう
じゃあ英国単位に換算してみましょう
03:57
2.5 times 10 to the 16th pounds
per cubic feet.
per cubic feet.
77
224968
4008
2.5 × 10^16
ポンド毎立方フィート です
ポンド毎立方フィート です
04:02
OK, that's still kind of hard to figure.
78
229864
1905
これでもまだ分かりにくいですよね
04:04
OK, here's what I want you to do.
79
231793
2101
では こうしてみてください
04:06
Make a box that is one foot
by one foot by one foot.
by one foot by one foot.
80
233918
3524
一辺が30センチの立方体をつくってください
04:10
Now let's go and grab
all of the nuclei from a typical car.
all of the nuclei from a typical car.
81
237466
3687
次に一般的な車から核を全て取ってみましょう
04:14
Now, cars on average weigh two tons.
82
241177
2334
車は平均して２トンです
04:16
How many cars' nuclei would you
have to put into the box
have to put into the box
83
243535
3536
30センチ四方の箱を原子核と同じ密度にするには
04:20
to have your one-foot-box have
the same density of the nucleus?
the same density of the nucleus?
84
247095
2953
何台の車の核を箱に詰めなければならないでしょう？
04:23
Is it one car? Two?
85
250072
1328
１台？２台？
04:24
How about 100?
86
251424
1000
100台ではどう？
04:26
Nope, nope and nope.
87
253025
2123
ダメ ダメ 全然ダメ
04:28
The answer is much bigger.
88
255825
1239
答えはずっと大きくて
04:30
It is 6.2 billion.
89
257702
2795
62億台です
04:34
That is almost equal to the number
of people in the Earth.
of people in the Earth.
90
261303
2893
地球上の人類の数にほぼ匹敵します
04:37
So if everyone in the Earth
owned their own car --
owned their own car --
91
264220
2334
地球上の人類全てが車を持っており
04:39
and they don't --
92
266578
1331
— 実際にはそんなことは無いのですが —
04:40
(Cars honking)
93
267933
1215
（ブー ブー）
04:42
and we put all of those
cars into your box ...
cars into your box ...
94
269172
2200
全ての車を箱に詰めたとしたら
04:46
That would be about
the density of a nucleus.
the density of a nucleus.
95
273148
2486
それが原子核の密度です
04:49
So I'm saying that if you took
every car in the world
every car in the world
96
276909
2544
世界中の全ての車を
04:52
and put it into your one-foot box,
97
279477
2331
30cmの箱に詰めたら
04:54
you would have the density of one nucleus.
98
281832
2144
原子核の密度が得られるのです
04:57
OK, let's review.
99
284000
1212
おさらいしましょう
04:58
The atom is really,
100
285236
1660
原子はとても とても とても
04:59
really, really small.
101
286920
2298
小さいのです
05:02
Think atoms in a grapefruit
like blueberries in the Earth.
like blueberries in the Earth.
102
289242
3366
グレープフルーツ内に存在する原子は
地球上に存在するブルーベリーのようなものです
地球上に存在するブルーベリーのようなものです
05:06
The nucleus is crazy small.
103
293396
2628
原子核は信じられない程小さいです
05:09
Now look inside the blueberry,
104
296048
1669
ブルーベリー内部を観察してみましょう
05:10
and blow it up to the size
of a football stadium,
of a football stadium,
105
297741
2415
フットボールスタジアム大にまで拡大してみると
05:13
and now the nucleus
is a marble in the middle.
is a marble in the middle.
106
300180
2143
原子核は中心に存在するビー玉程度です
05:16
The atom is made up
of vast regions of empty space.
of vast regions of empty space.
107
303417
3580
原子は広い空っぽの空間で構成されています
05:20
That's weird.
108
307608
1000
奇妙ですね
05:21
The nucleus has a crazy-high density.
109
308632
2220
核はありえないほど高い密度を持っています
05:23
Think of putting all those cars
in your one-foot box.
in your one-foot box.
110
310876
2477
全ての車を30cmの箱に詰め込んだ様子を想像してください
05:27
I think I'm tired.
111
314821
1308
疲れたなぁ
ABOUT THE SPEAKER
Jon Bergmann - EducatorJon Bergmann co-wrote the book on the "flipped classroom" -- using video to help students master new ideas outside the traditional class setting.
Why you should listen
Jon Bergmann is considered one of the pioneers in the Flipped Class Movement -- in fact, he co-wrote the book on the Flipped Classroom, available from ISTE Press in June 2012. Bergmann believes educators should ask one guiding question: What is best for my students in my classroom? To the best of his abilities he has done this in his two-plus decades as a high school science teacher. He received the Presidential Award for Excellence for Math and Science Teaching in 2002 and was named Semi-Finalist for Colorado Teacher of the Year in 2010. He blogs at flipped-learning.com.
He is the Lead Technology Facilitator for the Joseph Sears School in Kenilworth, Illinois.
Read about the making of "How Small Is an Atom?" >>
Jon Bergmann | Speaker | TED.com