Boaz Almog "levitates" a superconductor

773,189 views ・ 2012-07-02

TED


Dvaput kliknite na engleske titlove ispod za reprodukciju videozapisa.

00:00
Translator: Morton Bast Reviewer: Thu-Huong Ha
0
0
7000
Prevoditelj: SIBELA KESAC Recezent: Suzana Baric
00:25
The phenomenon you saw here for a brief moment
1
25012
4318
Fenomen koji ste vidjeli, u jednom kratkom trenutku
00:29
is called quantum levitation and quantum locking.
2
29330
6389
zove se kvantna levitacija i kvantno zaključavanje.
00:35
And the object that was levitating here
3
35719
3889
Objekt koji je levitirao
00:39
is called a superconductor.
4
39608
2001
zove se supravodič.
00:41
Superconductivity is a quantum state of matter,
5
41609
5592
Supravodljivost je kvantno stanje stvari,
00:47
and it occurs only below a certain critical temperature.
6
47201
4257
koje se događa samo ispod određenih temperatura.
00:51
Now, it's quite an old phenomenon;
7
51458
2346
Zapravo je to fenomen koji već dugo poznajemo.
00:53
it was discovered 100 years ago.
8
53804
1766
Otkriven je prije stotinu godina.
00:55
However, only recently,
9
55570
2126
Međutim, tek odnedavno,
00:57
due to several technological advancements,
10
57696
2362
zahvaljujući tehnološkom napretku,
01:00
we are now able to demonstrate to you
11
60058
2672
možemo vam demonstrirati
01:02
quantum levitation and quantum locking.
12
62730
3746
kvantnu levitaciju i kvantno zaključavanje.
01:06
So, a superconductor is defined by two properties.
13
66476
5845
Dakle, supravodič je određen dvama svojstvima.
01:12
The first is zero electrical resistance,
14
72321
3456
Prvo svojstvo je odsustvo električnog otpora,
01:15
and the second is the expulsion of a magnetic field from the interior of the superconductor.
15
75777
6889
a drugo je izbacivanje magnetskog polja iz unutrašnjosti supravodiča.
01:22
That sounds complicated, right?
16
82666
2895
Zvuči kompilcirano, zar ne?
01:25
But what is electrical resistance?
17
85561
2872
No, što je električni otpor?
01:28
So, electricity is the flow of electrons inside a material.
18
88433
6249
Elektricitet je protok elektrona unutar materijala.
01:34
And these electrons, while flowing,
19
94682
3349
I ti elektroni se u svom kretanju
01:38
they collide with the atoms, and in these collisions
20
98031
2688
sudaraju s atomima, i u tim sudarima
01:40
they lose a certain amount of energy.
21
100719
2216
gube određenu količinu energije.
01:42
And they dissipate this energy in the form of heat, and you know that effect.
22
102935
5601
Ta se energija rasipa u vidu zagrijavanja, i to vam je poznato.
01:48
However, inside a superconductor there are no collisions,
23
108536
5919
Međutim, unutar supravodiča nema sudaranja
01:54
so there is no energy dissipation.
24
114455
4692
i stoga nema rasipanja energije.
01:59
It's quite remarkable. Think about it.
25
119147
2981
To je zaista izvanredno. Razmislite o tome.
02:02
In classical physics, there is always some friction, some energy loss.
26
122128
5079
U klasičnoj fizici, uvijek imamo trenje, uvijek se gubi nešto energije.
02:07
But not here, because it is a quantum effect.
27
127207
4038
Ali, ne i ovdje, zbog toga što je riječ o kvantnom efektu.
02:11
But that's not all, because superconductors don't like magnetic fields.
28
131276
8686
Ali to nije sve, zato što supravodiči ne vole magnetna polja.
02:19
So a superconductor will try to expel magnetic field from the inside,
29
139962
4317
Zato supravodiči nastoje izbaciti magnetno polje iznutra,
02:24
and it has the means to do that by circulating currents.
30
144279
6123
a to rade uz pomoć kružnih struja.
02:30
Now, the combination of both effects --
31
150402
2990
Kombinacija oba efekta --
02:33
the expulsion of magnetic fields and zero electrical resistance --
32
153392
6000
izbacivanje magnetnog polja i izostanak električnog otpora
02:39
is exactly a superconductor.
33
159392
3168
jest supravodič.
02:42
But the picture isn't always perfect, as we all know,
34
162560
4216
No, kako to biva, slika nije uvijek savršena
02:46
and sometimes strands of magnetic field remain inside the superconductor.
35
166776
7385
i ponekad silnice magnetnog polja ostaju u supravodiču.
02:54
Now, under proper conditions, which we have here,
36
174161
3654
Sada, u odgovarajućim uvjetima, kakve imamo ovdje,
02:57
these strands of magnetic field can be trapped inside the superconductor.
37
177815
5090
silnice magnetnog polja mogu ostati zarobljene unutar supravodiča.
03:02
And these strands of magnetic field inside the superconductor,
38
182905
6257
A te silnice unutar supravodiča
03:09
they come in discrete quantities.
39
189162
2845
dolaze u malim količinama.
03:12
Why? Because it is a quantum phenomenon. It's quantum physics.
40
192007
3646
Zašto? Zato što je to kvantni fenomen. Kvantna fizika.
03:15
And it turns out that they behave like quantum particles.
41
195653
3850
I ispada da se one ponašaju poput kvantnih čestica.
03:19
In this movie here, you can see how they flow one by one discretely.
42
199503
5579
U ovom ovdje filmu možete vidjeti kako se diskretno kreću jedna po jedna.
03:25
This is strands of magnetic field. These are not particles,
43
205082
3893
Ovo su silnice magnetnog polja. Ovo nisu čestice,
03:28
but they behave like particles.
44
208975
4295
ali se ponašaju poput čestica.
03:33
So, this is why we call this effect quantum levitation and quantum locking.
45
213270
4194
Dakle, zbog toga se fenomen zove kvantna levitacija i kvantno zaključavanje.
03:37
But what happens to the superconductor when we put it inside a magnetic field?
46
217464
6063
No, što se dešava sa supravodičem kada ga stavimo unutar magnetnog polja?
03:43
Well, first there are strands of magnetic field left inside,
47
223527
4585
Pa, imamo silnice magnetnog polja koje su ostale unutra,
03:48
but now the superconductor doesn't like them moving around,
48
228112
4120
ali sada supravodiču više ne odgovara da se one kreću naokolo
03:52
because their movements dissipate energy,
49
232232
3448
jer njihovo kretanje rasipa energiju
03:55
which breaks the superconductivity state.
50
235680
2946
i to prekida stanje supravodljivosti.
03:58
So what it actually does, it locks these strands,
51
238626
4358
Tako da zapravo da zaključava te silnice,
04:02
which are called fluxons, and it locks these fluxons in place.
52
242984
5752
koje se zovu fluksoni. Zaključava fluksone u mjestu.
04:08
And by doing that, what it actually does is locking itself in place.
53
248736
6288
Na taj način on sam sebe zapravo zaključava u mjestu.
04:15
Why? Because any movement of the superconductor will change their place,
54
255024
9216
Zašto? Zato što svaki pokret supravodiča mijenja mjesto silnica
04:24
will change their configuration.
55
264240
1807
i njihovu konfiguraciju.
04:26
So we get quantum locking. And let me show you how this works.
56
266047
5297
I tako dobivamo kvantno zaključavanje. Pokazat ću vam kako to funkcionira.
04:31
I have here a superconductor, which I wrapped up so it'd stay cold long enough.
57
271344
5760
Ovdje imam supravodič koji sam umotao kako bi dovoljno dugo ostao hladan.
04:37
And when I place it on top of a regular magnet,
58
277104
4464
I kada ga stavim na običan magnet,
04:41
it just stays locked in midair.
59
281568
3872
on ostane zaključan u zraku.
04:45
(Applause)
60
285440
4065
(Pljesak)
04:49
Now, this is not just levitation. It's not just repulsion.
61
289505
4046
Pazite, ne radi se o levitaciji. Nije to obično odbijanje.
04:53
I can rearrange the fluxons, and it will be locked in this new configuration.
62
293551
5121
Mogu prerasporediti fluksone i bit će zaključan u ovoj novoj konfiguraciji.
04:58
Like this, or move it slightly to the right or to the left.
63
298672
4024
Na primjer, ovako. Ili ga mogu pomaknuti malo lijevo ili desno.
05:02
So, this is quantum locking -- actually locking -- three-dimensional locking of the superconductor.
64
302696
7751
Dakle, ovo je kvantno zaključavanje -- stvarno zaključavanje -- trodimenzionalno zaključavanje supravodiča.
05:10
Of course, I can turn it upside down,
65
310447
2160
Naravno, može se okrenuti i naglavačke
05:12
and it will remain locked.
66
312607
2906
i ostat će zaključan.
05:15
Now, now that we understand that this so-called levitation is actually locking,
67
315513
9222
Sada kada razumijemo da je tzv. levitacija zapravo zaključavanje,
05:24
Yeah, we understand that.
68
324735
4314
da, to smo shvatili.
05:29
You won't be surprised to hear that if I take this circular magnet,
69
329049
4262
Neće vas iznenaditi ako vam kažem da će, ako uzmem ovaj kružni magnet
05:33
in which the magnetic field is the same all around,
70
333311
3968
u kojem je magnetno polje jednako na svim djelovima,
05:37
the superconductor will be able to freely rotate around the axis of the magnet.
71
337279
5936
supravodič slobodno kružiti oko osi magneta.
05:43
Why? Because as long as it rotates, the locking is maintained.
72
343215
6024
Zašto? Zato što dokle god rotira, održava se zaključavanje.
05:49
You see? I can adjust and I can rotate the superconductor.
73
349239
6026
Vidite? Mogu namjestiti i rotirati supravodič.
05:55
We have frictionless motion. It is still levitating, but can move freely all around.
74
355265
6662
Imamo kretanje bez trenja. Još uvijek levitira, ali se može slobodno kretati uokolo.
06:01
So, we have quantum locking and we can levitate it on top of this magnet.
75
361927
9280
Dakle, imamo kvantno zaključavanje i mogućnost levitacije na vrhu magneta.
06:11
But how many fluxons, how many magnetic strands are there in a single disk like this?
76
371207
6496
No, koliko fluksona, koliko magnetnih silnica imamo u jednom ovakvom disku?
06:17
Well, we can calculate it, and it turns out, quite a lot.
77
377703
2881
Pa, možemo to izračunati i ispada da ih je mnogo.
06:20
One hundred billion strands of magnetic field inside this three-inch disk.
78
380584
7368
Stotinu milijardi silnica magnetnog polja nalazi se unutar jednog ovakvog diska veličine 7,6 cm.
06:27
But that's not the amazing part yet, because there is something I haven't told you yet.
79
387952
4104
Ali, to još nije nevjerojatan dio priče, zato što postoji nešto što vam još nisam rekao.
06:32
And, yeah, the amazing part is that this superconductor that you see here
80
392056
5616
Da, da, nevjerojatan dio priče je taj da je supravodič kojeg ovdje vidite
06:37
is only half a micron thick. It's extremely thin.
81
397672
7525
debeo samo pola mikrona. Izuzetno je tanak.
06:45
And this extremely thin layer is able to levitate more than 70,000 times its own weight.
82
405197
9562
I taj nevjerojatno tanki sloj može držati nešto 70,000 puta teže od vlastite težine.
06:54
It's a remarkable effect. It's very strong.
83
414759
5833
To je nevjerojatan efekt. Izuzetno snažan.
07:00
Now, I can extend this circular magnet,
84
420592
3577
Sada, mogu proširiti ovaj kružni magnet
07:04
and make whatever track I want.
85
424169
4781
i napraviti kakvu god traku želim.
07:08
For example, I can make a large circular rail here.
86
428950
3929
Na primjer, mogu napraviti veliku kružnu traku ovdje.
07:12
And when I place the superconducting disk on top of this rail,
87
432879
6883
I kada na traku stavim supravodljivi disk,
07:19
it moves freely.
88
439762
4109
on se slobodno kreće.
07:23
(Applause)
89
443871
9381
(Pljesak)
07:33
And again, that's not all. I can adjust its position like this, and rotate,
90
453252
4741
Ali opet, to nije sve, mogu ga namjestiti ovako i rotirati
07:37
and it freely moves in this new position.
91
457993
6441
i on se slobodno kreće u tom novom položaju.
07:44
And I can even try a new thing; let's try it for the first time.
92
464434
4438
I možemo probati i jednu novu stvar; probajmo to po prvi put.
07:48
I can take this disk and put it here,
93
468872
5944
Mogu uzeti ovaj disk, staviti ga ovdje,
07:54
and while it stays here -- don't move --
94
474816
2984
i dok je tu -- ne miči se --
07:57
I will try to rotate the track,
95
477800
6558
probat ću zarotirati traku,
08:04
and hopefully, if I did it correctly,
96
484358
2299
i nadati se, ako sam to dobro učinio,
08:06
it stays suspended.
97
486657
2143
da će tu ostati.
08:08
(Applause)
98
488800
9449
(Pljesak)
08:18
You see, it's quantum locking, not levitation.
99
498249
6841
Vidite, radi se o kvantnom zaključavanju, ne o levitaciji.
08:25
Now, while I'll let it circulate for a little more,
100
505090
4135
Sada, pustit ćemo ga da još malo kruži,
08:29
let me tell you a little bit about superconductors.
101
509225
3703
a ja ću vam reći nešto o supravodičima.
08:32
Now -- (Laughter) --
102
512928
5546
Sada-- (Smijeh) --
08:38
So we now know that we are able to transfer enormous amount of currents inside superconductors,
103
518474
7023
Sada znamo da možemo prenijeti ogromne količine struje unutar saupravodiča
08:45
so we can use them to produce strong magnetic fields,
104
525497
5223
pa ih možemo koristiti da bismo stvorili jaka magnetna polja,
08:50
such as needed in MRI machines, particle accelerators and so on.
105
530720
5186
koja su potrebna kod MRI uređaja, ubrzivača čestica, itd.
08:55
But we can also store energy using superconductors,
106
535906
4560
Ali unutar supravodiča možemo i spremiti energiju,
09:00
because we have no dissipation.
107
540466
1889
zato što nema rasipanja.
09:02
And we could also produce power cables, to transfer enormous amounts of current between power stations.
108
542355
7182
I možemo proizvesti kablove za prijenos ogromnih količina struje između elektrana.
09:09
Imagine you could back up a single power station with a single superconducting cable.
109
549537
9006
Zamislite da možete podržati cijelu elektranu sa samo jednim supravodljivim kablom.
09:18
But what is the future of quantum levitation and quantum locking?
110
558543
4476
No što je budućnost kvantne levitacije i kvantnog zaključavanja?
09:23
Well, let me answer this simple question by giving you an example.
111
563019
7139
Pa, odgovorit ću vam na ovo jednostavno pitanje jednim primjerom.
09:30
Imagine you would have a disk similar to the one I have here in my hand,
112
570158
6413
Zamislite da imate disk koji je nalik ovom ovdje kojeg imam u ruci,
09:36
three-inch diameter, with a single difference.
113
576571
3879
7,6 centimetara u promjeru, sa samo jednom razlikom.
09:40
The superconducting layer, instead of being half a micron thin,
114
580450
5185
Supravodljivi sloj, umjesto debljine jednog mikrona,
09:45
being two millimeters thin, quite thin.
115
585635
3088
bude debljine dva milimetra, i dalje jako tanak.
09:48
This two-millimeter-thin superconducting layer could hold 1,000 kilograms, a small car, in my hand.
116
588723
10735
Takav supravodljivi sloj od dva milimetra može držati 1.000 kilograma, manji auto, u mojoj ruci.
09:59
Amazing. Thank you.
117
599458
3296
Zadivljujuće. Hvala vam.
10:02
(Applause)
118
602754
15080
(Pljesak)
O ovoj web stranici

Ova stranica će vas upoznati s YouTube videozapisima koji su korisni za učenje engleskog jezika. Vidjet ćete lekcije engleskog koje vode vrhunski profesori iz cijelog svijeta. Dvaput kliknite na engleske titlove prikazane na svakoj video stranici da biste reproducirali video s tog mjesta. Titlovi se pomiču sinkronizirano s reprodukcijom videozapisa. Ako imate bilo kakvih komentara ili zahtjeva, obratite nam se putem ovog obrasca za kontakt.

https://forms.gle/WvT1wiN1qDtmnspy7