00:00:11
It's interesting that some people find science so easy
00:00:14
and others find it kind of dull and difficult
00:00:18
especially kids you know, some of them are just eat it up
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and I don't know why it is, it's the same perhaps for all subjects
00:00:25
For instance lot of people love music and I could never carry a tune
00:00:28
and I lose a great deal a pleasure out of that
00:00:33
and I think that people lose a lot of pleasure who find the science dull
00:00:37
In the case of science, I think that one of the things that make it very difficult
00:00:43
is that it takes a lot of imagination
00:00:44
It's very hard to imagine all the crazy things that things really are like
00:00:54
Nothing's really as it seems, we used to get you know hot and cold
00:00:58
and all that hot and cold is the speeds that the atoms are jiggling
00:01:03
if they jiggle more it corresponds to hotter and colder is jiggling less
00:01:07
So if you have a bunch of atom, like a cup of coffee or something, sitting on a table
00:01:15
and the atoms are jiggling a great deal and they bounce against the cup
00:01:20
and the cup then gets shaking and the atoms in the cup shake
00:01:23
and the bounce against each other and the heat heats the cup and heats everything else
00:01:26
and then hot things spread that heat to other by mere contact
00:01:32
because the atoms that are jiggling a lot in the hot thing
00:01:35
shake the ones that are jiggling only a little bit in the cold thing
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so that the hot (heat we say) goes into the cold thing, it spreads
00:01:45
but what is spreading is just jiggling, an irregular motion, but it is easy to kind of understand.
00:01:53
It brings up another thing that's kind of curious:
00:01:58
that I say that things jiggle and if you're used to balls bouncing
00:02:04
you know they slow up and stop after a while
00:02:08
but we have to imagine with the atoms a perfect elasticity they never lose any energy
00:02:13
every time they bounce they keep on bouncing all the time they don't lose anything
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they're perpetually moving
00:02:18
And that the things that happen when we say something loses energy
00:02:21
if a ball comes down and bounces,
00:02:24
it shakes irregularly some of the atoms in the floor
00:02:27
and when it comes up again, it leaves some of the atoms moving, they jiggling
00:02:32
So as it bounces, it is passing its extra energies, its extra motions
00:02:38
to little patches on the floor each time it rebounces and it loses a little heat each time
00:02:43
until it settles down, we say as the falling motion stops
00:02:47
But what's left is the floor is shaking more than it was before
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and the atoms in the ball are shaking more than they were before
00:02:53
that the organized motion of all these atoms moving the same way falling down
00:02:58
and the quiet floor, is now transformed into a ball sitting on the ground
00:03:03
But all the motion is still there in the form of energy of motion
00:03:07
in the form of the jiggling of the floor which is a little bit warmer (unbelievable!).
00:03:12
But anybody who's hammered a great deal on something knows that it's true
00:03:16
that if you pound something and hit it a lot
00:03:19
you can feel the temperature difference it heats up
00:03:21
it heats up simply because you're jiggling it
00:03:25
this picture of atoms is a beautiful one
00:03:27
that you can keep looking at all kinds of things this way
00:03:29
you see a little drop of water a tiny drop
00:03:34
and the atoms attract each other they like to be next to each other
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they want as many partners as they can get
00:03:40
Now the guys at the surface have only partners on one side
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here in the air on the other side so they're trying to get in
00:03:47
And you can imagine this team of people, this team in people, all moving very fast
00:03:52
all try (to get) to have as many partners as possible
00:03:55
and the guys on the edge are very unhappy and nervous and they keep pounding in
00:03:59
trying to get in, and that makes a tight ball instead of a flat
00:04:03
and that's what you know surface tension
00:04:05
when you realize when you see how sometimes a water drop sits like this on a table
00:04:10
then you start to imagine why it's like that
00:04:13
because everybody is trying to get in to the water
00:04:15
and at the same time while all this is happening, other atoms leaving the surface
00:04:20
and the water drop is slowly disappearing
00:04:23
I find myself trying to imagine all kinds of things all the time
00:04:26
and I get a kick out of it like a runner gets a kick out of sweating
00:04:30
I GET A KICK of thinking about these things!
00:04:36
I can't stop I mean if you may I could talk forever
00:04:40
If you could cool off the water
00:04:42
so that the jiggling is less and less, it jiggles slower and slower
00:04:45
then the atoms get stuck in a place, they like to be with their friend
00:04:49
there's force of attraction and they get packed together,
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they're not rolling over each other, they're in a nice pattern
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like oranges in a crate in a nice organized pattern, all just jiggling in place
00:05:01
but not having enough motion to get loose of their own place
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and to break the structure down
00:05:07
And that what I'm describing is a solid, it's ice, it has a structure
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If you held the atom in one end in a certain position
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all the rest are lining up in a position sticking out
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and it’s solid at the end
00:05:19
whereas if you heat that harder
00:05:21
then they begin to get loose and roll all over each other
00:05:24
and that's the liquid.
00:05:25
And if you heat that still harder, then they bounce still harder
00:05:28
and they simply bounce apart from each other
00:05:30
and they're just individuals,
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I said atoms, these are really little groups of atoms: molecule
00:05:35
which come flying and hit
00:05:37
and although they have a tendency to stick, they're moving too fast
00:05:41
their hands don't grab so to speak, as they pass
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and they fly apart again and this is the gas we call steam
00:05:50
You can get all kinds of understanding
00:05:52
When I was a kid with this "air", I was always interested in
00:05:56
I've noticed that when I pumped up my tires on the bicycle
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you can learn a lot by having a bicycle
00:06:01
I'd pump up the tires that the pump would get hot
00:06:04
and that also understand we see as the pump handle comes down
00:06:08
and the atoms are coming up against it and bouncing off and it's moving in
00:06:11
the ones that are coming off have a bigger speed than the ones that are coming in
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so that as it comes down and each time they collide
00:06:18
it speeds them up
00:06:20
and so they're hotter when you compress the gas it heats
00:06:22
and when you pull the piston back out
00:06:25
then the atoms which are coming faster than the piston feel receiving
00:06:28
or sort of a give it gives and it comes out with less energy
00:06:32
it's like going up against something which is soft and yielding it go boom boom
00:06:36
and it loses so as you pull the piston out
00:06:38
and the atoms are hit they lose their speed and they cool off
00:06:42
and gases are cool when they expand
00:06:45
and the fun of it is that all these things which you see or you notice in the world
00:06:50
about it the pump heats the gas and the gas cools when it expands
00:06:54
or the steam evaporates until you cover the cover
00:06:57
and all these things you can understand from these simple pictures
00:07:01
and that's kind of a lot of fun to think about
00:07:04
I don't want to take this stuff seriously
00:07:06
I think we should just have fun imagining it not worry about
00:07:10
there's no teacher going to ask you questions at the end
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otherwise it's a horrible subject
00:07:21
the atoms like each other the different degrees
00:07:26
oxygen for instance in the air would like to be next to carbon
00:07:29
and if they're getting near each other they snap together
00:07:34
if they're not too close though they repel and they go apart
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so they don't know that they could snap together
00:07:39
it's just as if you had a ball that was trying to climb a hill
00:07:41
and there was a hole it could go into like a volcano hole
00:07:45
a deep one it's rolling along it doesn't go down in the deep hole
00:07:49
because if it starts to climb the hill and then rolls away again
00:07:52
but if you made it go fast enough it'll fall into the hole
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and so if it's have something like wood in oxygen
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there's carbon in the wood from a tree
00:08:03
and the oxygen comes and hits it carbon but not hot enough
00:08:08
it just goes away again the air is always coming nothing's happening
00:08:12
if you can get it faster by heating it up somehow somewhere
00:08:16
somehow get it started a few of them come fast they go over the top so to speak
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they come close enough to the carbon and snap in
00:08:22
and that gives a lot of jiggly motion which might hit some other atoms
00:08:26
making those go faster so they can climb up and bump against other carbon atoms
00:08:31
and they jiggle and they make other jiggle, and you get an horrible catastrophe
00:08:35
which is one after the other all these things are going faster and faster
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and snapping in and the whole thing is changing
00:08:41
that catastrophe is a fire
00:08:45
it's just a way of looking at it
00:08:46
and these things are happening they perpetual
00:08:48
once it gets started it keeps on going
00:08:50
the heat makes the other atoms capable of reaching to
00:08:54
make more heat to make other atoms and so on
00:08:56
so this terrible snapping is producing a lot of jiggling
00:09:00
and if I put with all lack activity of the atoms there
00:09:03
and I put a cup of coffee over that mess of wood that's doing this
00:09:08
it's going to get a lot of jiggling so that's what the heat of the fire is
00:09:13
and then of course uh
00:09:14
you see what's happening when you start thinking, just go on and on
00:09:18
wonder how did it get started
00:09:21
why is it that the wood's been sitting around all this time with the oxygen all this time and it didn't do this earlier or something
00:09:27
where did I get this from？
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well it came from a tree
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and the substance of a tree is carbon, where did that come from?
00:09:38
that comes from the air it's carbon dioxide from the air
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people look at trees and they think it comes out of the ground
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the plants grow out of the ground
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but if you ask where the substance comes from
00:09:49
you find out where do they come from
00:09:51
the trees come out of the air?
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they surely come out of you know they come out of the air
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the carbon dioxide in the air goes into the tree
00:09:59
and it changes it kicking out the oxygen
00:10:03
and uh pushing the oxygen away from the carbon
00:10:06
and leaving the carbon substance with water water comes out of the ground you see
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only it had to get in there it came out of the air didn't it
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it came down from the sky
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so in fact most of a tree almost all of the tree is out of the ground
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I'm sorry it's out of the air
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there's a little bit from the ground some minerals and so forth
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now of course I told you the oxygen and we…
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oxygen carbon stick together very tight
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how is that the tree is so smart to take the carbon dioxide
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which is carbon and oxygen nicely combined
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and undo that so easy?
00:10:42
Ah! Life! Life has some mysterious force!
00:10:45
No! The sun is shining, and this sunlight comes down
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and knocks this oxygen away from the carbon,
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so it takes sunlight to get the plant to work!
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and so the sun, all the time, is doing the work of separating the oxygen away from the carbon
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the oxygen is some kind of terrible by-product, which it spits back into the air
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and leaving the carbon and water and stuff to make the substance of the tree
00:11:09
and then we take the substance of the tree to get the fireplace
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and there's all the oxygen made by these trees
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and all the carbons would much prefer to be close together again
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and once you let the heat to get it started
00:11:24
it continues and make an awful lot of activity while it's going back together again
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and all those nice light and everything comes out
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and everything is being undone you're going from carbon and oxygen back to carbon dioxide
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and the light and heat that's coming out, that's the light and heat of the sun that went in
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so it's sort of stored sun that is coming out when you burned a log
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next question: how is the sun so jiggly, so hot?
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I gotta stop somewhere; I leave you something to imagine
00:12:12
most elastic things like steel springs and so on is nothing but this electrical thing pulling back
00:12:18
you pull the atoms up a little bit apart when you bend something
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and then they try to come back together again
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but rubber bands work on a different principle
00:12:28
there there's some long molecules like chains
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and other little ones that are shaking all the time that are bombarding them these chains
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and the chains are all kind of kinky and knockabout in shape
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when you pull open the rubber band the strings get straighter
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but these strings are being bombarded on the side
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by these other atoms trying to shorten them by kinking them
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so it pulls back it's trying to pull back
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and it's pulling back only because of the heat
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so if you heat a rubber band it'll pull strong more strongly
00:13:02
for instance if you hang a weight with a rubber band put a little match to it
00:13:06
it's kind of fun to watch it rise because heats want
00:13:08
and there's another thing you can check that this idea is right
00:13:12
that is heat that drives a rubber band
00:13:15
if you pull the band out just like when we push the piston and the gas
00:13:20
if you pull the band out
00:13:21
this tightening string hitting those molecules makes them move faster so it's warmer
00:13:27
and if you take the band and let it in
00:13:31
then the molecules hitting the strings which sort of give as the thing hits it
00:13:35
they give in to the soft like and they lose energy when they hit these retiring band, string
00:13:44
so it cools
00:13:46
and there is a little way you can do this
00:13:47
you're not very sensitive it's a small effect
00:13:49
and if you take a fairly wide rubber band and put it between your lips
00:13:53
and pull it out you'll certainly notice it's hotter
00:13:57
and if you then hold it out and let it in you'll notice it's cooler
00:14:00
at least you'll notice a certain difference in whether
00:14:03
what happens when you expand it and when you contract it
00:14:05
and that's i've always found rubber bands fascinating to think
00:14:09
that when they're sitting on an old package of papers for a long time
00:14:14
holding those papers together
00:14:16
it's done by a perpetual pounding pounding pounding
00:14:19
and the atoms that get these chains to hold it, try to kink them and try kink them
00:14:23
year after year well rubber bands don't last that long
00:14:26
but anyhow for a long time trying to hold this whole thing together
00:14:31
The world is a dynamic mess of jiggling things if you look at it right
00:14:36
And if you magnify, you will hardly see a little thing anymore
00:14:39
because everything is jiggling in its own pattern, and there's a lot of little balls
00:14:43
It's lucky that we have such a large scale of view of everything that we can see these as "things"
00:14:48
without having worry about all these little atoms all the time
00:14:57
If you get hold of two magnet and you push them
00:15:00
you can feel this pushing between them.
00:15:02
Turn around the other way and they slam together
00:15:05
Now, what is it, the feeling between those two magnets?
00:15:09
what do you mean "what's the feeling between two magnets when you hold them"?
00:15:11
well, there's something there, isn't it?
00:15:12
I mean that the sensation that they're something there when you push the two magnets together.
00:15:17
Listen to my question
00:15:18
what is the meaning when you say that there's there's a feeling
00:15:21
of course you feel it. Now what do you want to know?
00:15:24
What I want to know is what's going on, between these two bits of matter?
00:15:29
magnets repel each other
00:15:30
Well then, what does that mean or why are they doing that or how are they doing that?
00:15:40
I'm not saying... That's a perfectly reasonable question.
00:15:42
Of course it's a reasonab... it's an excellent question. Okay?
00:15:49
But the problem that you are asking, you see,
00:15:51
when you ask why something happens
00:15:56
how does a person answers "why something happens?"
00:16:00
for example
00:16:03
Aunt Minnie is at the hospital. Why? Because she slip.
00:16:07
she went out and she slipped on the ice and broke her hip
00:16:10
that satisfies people. It satisfies
00:16:14
but wouldn't satisfy someone who came from another planet knew nothing about things
00:16:17
first you understand "Why when you break your hip you go to the hospital?
00:16:22
"How do you get to the hospital when the hip is broken"
00:16:25
well because her husband seeing that she had her hip broken
00:16:28
called the hospital up and send somebody to get her
00:16:30
all that is understood by people
00:16:33
now when you explain a "Why"
00:16:36
you have to be in some framework that you allow something to be true
00:16:41
Otherwise you are perpetually asking why
00:16:43
Why did the husband call up the hospital?
00:16:45
Because the husband is interested in his wife's welfare. Not always
00:16:50
some husbands aren't interested in their wives' welfare when they are drunk and angry
00:16:54
So you begin to get very interesting understanding of the world and all its complications
00:16:59
in order to… if you try to follow anything up
00:17:02
you go deeper and deeper in various directions.
00:17:05
for example you could go “why did she slip upon the ice?"
00:17:08
Well ice is lippery everybody knows that no problem
00:17:12
But you ask "why is ice slippery?"
00:17:15
that's kind of curious, ice is extremely slippery it's very interesting
00:17:19
You say "How does it work?"
00:17:21
you could either say "I'm satisfied that you have answered me ice is slippery, that explains it"
00:17:27
or you could go on and say "Why is ice slippery?”
00:17:31
and then you're involved with something
00:17:32
because there are not many things as slippery as ice
00:17:35
It's very hard to get greasy stuff, but that's a sort of wet slimy
00:17:40
But a solid that is so slippery? Because it is in the case of ice
00:17:46
when you stand on it (they say), momentarily the pressure melts the ice a little bit
00:17:51
so you get a sort of instantaneous water surface on which you are slipping
00:17:56
Why on ice and not on other things?
00:17:57
Because ice expands… water expands when it freezes
00:18:01
so the pressure tries to undo the expansion and melts it.
00:18:04
It is capable about melting it
00:18:05
But other substances contract when they're freezing
00:18:08
and when you push them they're just satisfied to be solid
00:18:13
why does water expand when it freezes
00:18:15
and another substance don't expand when they freeze
00:18:17
all right? I'm not answering the question
00:18:19
but I am telling you how difficult a "why" question is.
00:18:22
You have to know what it is that you are permitted to understand
00:18:27
and allow to be understood and known
00:18:29
and what it is you're not
00:18:31
you'll notice in this example that the more I ask why, it gets interesting after all
00:18:36
that's my idea that the deeper thing is the more interesting in it
00:18:40
and you can even go further and say "Why did she fall down when she slip?"
00:18:46
That has to do with gravity
00:18:47
and involves all other planets, and everything else
00:18:49
never mind, it goes on and on!
00:18:52
Now when you ask for example "Why two magnets repel?"
00:18:56
there are many different levels
00:18:58
it depends on whether you are a student of physics
00:19:00
or an ordinary person who doesn’t know anything or not
00:19:02
If you are somebody that doesn't know anything about
00:19:04
all I can say is that it is the magnetic force that makes things repel
00:19:08
And that you are feeling that force. You see, that is very strange
00:19:13
because I don't feel kind of force like that in other circumstances.
00:19:16
When you turn them in the other way they attract
00:19:18
there's a very analogous force, electrical force
00:19:21
which is the same kind of a question and you say that's also very weird
00:19:25
but you're not at all disturbed by the fact
00:19:26
that when you put your hand on the chair, it pushes you back.
00:19:30
But we have find that looking at it that it is the same force as a matter of fact
00:19:34
the electrical force (not magnetic exactly in that case)
00:19:37
but it is the same electric repulsions that are involved in keeping you finger away from the chair
00:19:42
because everything is made out... it is electrical force in minor, microscopic details
00:19:48
there are other forces involved, but they are connected to electrical force
00:19:52
It turns out that the magnetic and the electric forces with which I wish to explain these things
00:19:56
this repulsion in the first place
00:19:59
is what ultimately is the deeper thing that we have to start
00:20:02
that we can start with to explain many other things that looks like they were...
00:20:07
Everybody would just accept them.
00:20:09
You know you cannot put your hand through the chair, that's taken for granted.
00:20:14
But you can't put your hand through the chair when you look at it more closely: "Why?"
00:20:18
it involves these same repulsive forces that appear in magnets
00:20:23
The situation is then to have to explain is:
00:20:25
"why in the magnet it goes over a bigger distance than ordinarily?"
00:20:28
There it has to do with the fact that in iron, all the electrons are spinning in the same direction,
00:20:34
they all get lined up and they magnify the effect of the force
00:20:38
until it's large enough at a distance that you can feel it
00:20:41
but it's a force which is present all the time and very common
00:20:45
and is in a basic force or almost
00:20:48
I mean I can go a a little further back if I went more technical
00:20:51
but in the early level, I just have to tell you
00:20:54
that is going to be one of the thing you will have to take as an element in the world
00:20:58
the existence of magnetic repulsion or electrical or magnetic attraction
00:21:04
I can't explain that attraction in terms of anything else that is familiar to you.
00:21:10
For example, if we say that the magnets attracts like if they were connected by rubber bands
00:21:15
I would be cheating you
00:21:17
because they are not connected by rubber bands; I shouldn't be in trouble
00:21:20
you'll soon ask me about the nature of the bands
00:21:23
And secondly, if you are curious enough you will ask me
00:21:26
"why rubber bands tend to pull back together again?"
00:21:29
I would end up explaining that in terms of electrical forces
00:21:33
which are the very things I try to use the rubber band to explain
00:21:36
so I have cheated very badly you see
00:21:40
So I'm not going to be able to give you an answer to "why magnets attract each other"
00:21:44
except to tell you that they do
00:21:47
and to tell you that's one of the elements in the world among different forces:
00:21:51
there are electrical forces, magnetic forces,
00:21:53
gravitational forces and others, and those are some of the parts
00:21:58
If you are a student, I could go further and tell you
00:22:01
that the magnetic forces are related to the electrical forces very intimately
00:22:06
that the relationship between the gravity forces and the electrical forces remains unknown
00:22:11
and so on.
00:22:13
But I really can't do a good job, any job of explaining magnetic forces in terms of something else that you are more familiar with,
00:22:21
because I don't understand it in terms of anything else that you are more familiar with.
00:22:31
The stuff of fantasizing in looking at the world, imagining things, which really isn't fantasizing
00:22:37
because you just try to imagine the way it really is, comes up handy sometimes
00:22:43
The other day I was at the dentist, he was getting ready with this electric drill to make holes
00:22:49
and I thought I'd better think of something fast or else it's gonna hurt.
00:22:54
And then I thought about this little motor going around
00:22:57
and what was that make it turn? And what was going on?
00:23:02
and what's going on is that there's a dam some distance away here
00:23:07
and water going over the dam turns a great big wheel, alright
00:23:12
and this wheel is connected with long thin pieces of copper
00:23:19
which split up into other pieces of copper and split up and spread all over the city
00:23:24
and then they're connected back to another little gadget and makes wheels turn
00:23:29
all the wheels in the city are turning, because this thing turns.
00:23:33
If this thing stops, all the wheels stop. If it starts again, they all start again.
00:23:38
And I think it's kind of a marvelous thing of nature. It's extremely curious that phenomenon
00:23:46
I like to think about a lot, because all it is, it's copper and iron.
00:23:51
see, sometimes we think it's man-made generator very complicated,
00:23:54
the phenomenon is a result of somet special something that we've made.
00:23:59
But it's nature doing it, and it's just iron and copper; if you just take a big long loop of copper,
00:24:06
and add iron at each end and move the piece of iron here, the other iron move at the other piece.
00:24:11
And if you get it down to the NOTHING
00:24:14
here just moving piece of iron in a loop a copper and see other piece of iron move
00:24:19
you realize what a fantastic mystery nature is!
00:24:27
you don't even need the iron
00:24:30
you could if you at least get this pump prime primed and started by
00:24:35
jiggling copper strands around fast enough knotting them and unknotting them and so forth
00:24:40
you can get other copper strands move at the other end, over a long connection.
00:24:45
And what is it? It's only copper! And motion!
00:24:51
We're so used to circumstances in which these electrical phenomena are all canceled out
00:24:59
Everything is sort of neutral: pushing and pulling, it's all very dull.
00:25:03
But nature has these wonderful things
00:25:05
Magnetic forces and electrical forces when you comb your hair
00:25:08
with your comb and you get some strange condition
00:25:11
so you put it in front of a piece a paper, that lifts up the paper, the paper jiggles at a distance far away
00:25:18
that in fact turns out that that is the thing that's deeper inside of everything than the things we're used to
00:25:30
We're used to forces that only act directly, right?
00:25:33
you push with your finger, it only acts directly,
00:25:37
but then you have to imagine what it is that's pushing with the finger
00:25:40
here's this finger is made of little balls of atoms.
00:25:44
And it has got another bunch of atoms that are pushing it.
00:25:47
At that little space between those atoms. And that pushing is going through that space.
00:25:52
And the only thing that happens with the comb and the paper is that the circumstances have a reason
00:25:59
which makes it possible to see those forces go through a bigger distance than just the short distance between the atoms
00:26:08
What it is they have charges like electrons, that are both the same
00:26:13
they repel each other with a force. They are very tiny parts, they are piece of the atoms
00:26:17
and they repel each other with a force which is enormous
00:26:21
it's inversely as the square of the distance just like gravity is inverse to the square of the distance
00:26:26
but gravity is attractive whereas this one is repulsive
00:26:29
and for two electrons the gravity is so weak compared to the electricity
00:26:34
electricity is so much more enormous than the gravity
00:26:37
I can't express because I don’t know the name of the numbers
00:26:39
it's one with thirty eight or forty zeros after the one
00:26:44
Bigger is electricity!
00:26:45
It's so enormous, that if I were all electrons... well, the number is too big!
00:26:54
There's also however for electrical thing other kind of charges, positive charges
00:26:59
example of protons are positive, they're inside the nucleus of the atoms and the attract electrons
00:27:04
Opposite charges attracts, alike charges repel
00:27:07
So you have to imagine enormous forces
00:27:11
where likes are trying to get away from likes, and unlikes are trying to get near the opposite
00:27:17
What would happen if you had a lot of them?
00:27:19
they'd be all the likes would collect with unlike, they attract each other
00:27:24
and they'd get an intimate mixture of pluses and minuses all on top of each other, very close together
00:27:29
You wouldn't have a lot of pluses anywhere, because they repel each other
00:27:32
They're all being compensated with minus very close,
00:27:35
and you get these little knots of plus and minus
00:27:38
the reason that the knots don't get smaller and smaller is because they are particles and there are quantum mechanical effects
00:27:43
that we won’t discuss that don’t make they can't get any smaller than a certain size
00:27:47
So you get these little lumps which are balls, they are the atoms
00:27:52
The atoms are positive and negative charges and they neutralize
00:27:55
they cancel their charges as nearly as they can
00:27:58
and because of these force are so big, it ends up nowhere, with very little left
00:28:04
because they're so big they cancels out, there's always so exactly the same pluses and minuses in any normal material
00:28:11
When you comb your hair, it rubs just a little bit extra off
00:28:15
just a few extra minuses say here, and somewhere else a few extra pluses
00:28:19
But the forces are so big that just the extra ones
00:28:23
which make a force that we can see, that seems to get over a long range
00:28:28
and that we find mysterious and that we need an explanation for
00:28:33
and we try to find an explanation for it in terms of ideas
00:28:36
like forces that are inside of rubber bands, or steel bars and twisted things
00:28:42
We would like to have some kind of puller, at a distance
00:28:45
because we're used to it that we don't get any push until we're touching
00:28:49
but the fact is that the reason we don't get any push until we're touching
00:28:52
is the same force as you see at a long distance only it's come down to short
00:28:57
because the pluses and minuses have cancelled out so well that you don't feel anything until it gets very very close
00:29:03
When it gets close enough of course it makes a difference
00:29:05
which is plus and which is minus and where they are and they repel each other
00:29:08
so it's kind of fun to imagine that this intimate mixture of highly attractive opposites
00:29:16
which are so strong that they cancel out the effects
00:29:18
and it's only sometimes, when you have an excess of one kind or another that you get this mysterious electrical force
00:29:28
And how can I explain the mysterious electrical forces in any other way?
00:29:31
Why should I try to explain it in terms of something like jelly or other things which are made?
00:29:39
And I understand the other way around in terms of strong, long distance forces which are all canceled out
00:29:45
So it's the electrical forces in fact, and the magnetic forces in fact that we have to accept as the base reality
00:29:54
in which we are going to explain all the other things.
00:29:58
So again it turns out it's hard to understand, you have to do a lot of imagining
00:30:02
that the real world has as its base, a force that acts at long distance
00:30:10
that we haven't got much experience with that force
00:30:14
we have peculiar phenomena here and there, but ordinarily
00:30:18
we don't have much experience with that force is simply because that's what requires explanation
00:30:23
That's what requires imagination. The long distance force we haven't other picture for
00:30:30
And in the example of the generator for instance
00:30:38
what happens is that the electrons which are part of an atom
00:30:43
they're pushed by the motion of the copper wires
00:30:50
wonderful to think that if you push a few here, and they get too close together
00:30:54
so they push the others because they repel at a long distance
00:30:56
so it's not just like water which repel at a short distance
00:30:59
but it's a wonderful fluid which repel at a long distance
00:31:03
and the effects therefore can go very quickly through the wire
00:31:05
there is a little concentration you go ZINNNG through the wire all over the city at once.
00:31:09
And you can use that stuff to make signals,
00:31:13
you can push a few electrons here and there by talking in a telephone,
00:31:16
at the other end of the line, a long line of copper across the city the electrons respond
00:31:22
because of this very rapid interactions over these long distances to what you're saying in this room
00:31:28
and they discovered experimentally
00:31:32
the existence of these long forces and that this rapid motion action and so forth
00:31:38
was a tremendous thing for human beings
00:31:40
I think that the discovery of electricity and magnetism and the electromagnetic effects
00:31:45
which are finally worked out, the full equations were worked out by Maxwell in 1873
00:31:52
probably the most fundamental transformation, the most remarkable thing in history
00:32:00
the biggest change in history
00:32:10
I went to a scientific school-MIT, and then fraternity when you first join
00:32:16
they try to keep you from being feeling that you're too smart
00:32:22
by giving you what looked like simple questions to try to figure out what actually happens
00:32:27
and it's like training for imagination you know, it's kind of fun
00:32:31
and I'd tell you some of them that I remember
00:32:34
I learned them of course once you learn them
00:32:36
the next time somebody comes along with this wonderful puzzle
00:32:40
you look at them kind of quietly you wait two or three seconds or five seconds
00:32:43
to show ways that you were thinking
00:32:45
and then you come up with this answer to astonish your friends
00:32:49
but the fact was of course that you were trained by your fraternity brothers
00:32:52
as to how to answer these things early on
00:32:55
one of the questions we used to we got was the problem about the mirror
00:32:59
it's an old-fashioned it's an old problem
00:33:02
You look in a mirror, and let's say you part your hair in the right side
00:33:07
and you look in the mirror and the image has got its hair part on the left side
00:33:10
so the image is left to right mixed up it's not top and bottom mixed up
00:33:15
because the top of the head of the image is on the top and the bottom of the feet are at the bottom
00:33:20
and the question is how does the mirror know to get the left and right mixed up and not the up and down
00:33:25
you get a better idea of the problem if you think of lying down and looking at the mirror
00:33:30
all right your hair is still on the left side
00:33:32
and now the left and right was the up and down
00:33:35
Whereas the up and down which look okay was the left and right before
00:33:38
and the mirror somehow figured out what you are gonna do when you're looking at it
00:33:42
so what to describe in a sort of symmetrical way what the mirror does
00:33:47
that it doesn't look lopsided and it takes left and mixes it up with right
00:33:50
and doesn't do the same with up and down
00:33:54
and after a lot of fiddling you gradually read we can worked out the answer to that one
00:33:59
you see if you wave this hand
00:34:02
then the hand in the mirror that waves is the right opposite at it
00:34:05
The hand on the east is the hand on the east and the hand on the west is the hand on the west,
00:34:10
and the hand that head that up is up and the feet that is down is down.
00:34:14
Everything is really all right!
00:34:16
but what's wrong is if this is north
00:34:19
your nose is to the north of the back of your head,
00:34:22
but in the image the nose is to the south of the back of the head
00:34:26
so what happens really in the image is neither the left and the right mixed nor the top and the bottom,
00:34:31
but the front and back had been reversed, you see
00:34:33
that is just the nose of the thing is on the wrong side of the head if you want it, all alright?
00:34:38
Now ordinarily when we think of the image we think at it as of another person
00:34:42
and we think the normal way that another person would get on that condition over there
00:34:45
It's a psychological thing
00:34:47
We don't think of the idea that the person has been squashed and pushed backward with his nose and his head
00:34:52
because that's not what ordinarily happens to people
00:34:54
A person gets to look like you looks in the mirror by walking around and facing you
00:35:00
and because people when they walk around don't turn their head for their feet
00:35:04
we leave that part alone
00:35:05
but they get their right and left hand swung about you see when they turn around
00:35:09
so we say that it's left and right interchanged
00:35:13
but really the symmetrical way is along the axis of the mirror that thing get interchangeable
00:35:17
but that's kind of an easy one
00:35:19
a harder one and very entertaining was
00:35:22
"what keeps a train on the track?"
00:35:25
And of course the answer is, as everyone thinks: the flanges on the wheels
00:35:30
you know the wheels have some kind of flange on them
00:35:32
but that's not the answer. Because flange is just safety devices
00:35:36
if the flanges rub against the tracks you hear a terrible squealing
00:35:40
they're just in case the real mechanism doesn't work
00:35:44
there's another problem with trains that's connected to it
00:35:47
now people all know this about their automobile that when you go around the corner
00:35:53
the outside wheels have to go further than the inside wheels
00:35:56
and if the wheels were connected on a solid shaft
00:35:59
you couldn't do that you can't turn the outside wheels further than the inside wheels
00:36:04
and so the shaft is broken in the middle with a gear system it's called a differential
00:36:09
did you ever see the differential on a railroad train?
00:36:12
no you look at those wheels under a freight car
00:36:15
and there are the two wheels
00:36:16
and there's a solid steel rod going from one wheel to the other
00:36:20
there's nothing that one turns the same as the other
00:36:22
so now how does it go around the corner, a curve?
00:36:25
when the outside wheel has to go further than the inside wheel
00:36:29
and the answer is that the wheels are flanged like this
00:36:33
I mean not flange they're cones this way
00:36:38
that is they're a little fatter closer to the train and a little thinner further out
00:36:42
if you look closely you'll see they've got this beveled edge
00:36:45
and it's all very simple
00:36:46
when they go around the curve, they slide out on the track a bit
00:36:51
So that this wheel travels on a fatter pond a bigger diameter
00:36:56
and this on a smaller diameter
00:36:57
so when they both turn one turn this swings further than the other
00:37:03
and that's what keeps it on the track also the same way
00:37:05
suppose the train's running along on this thing, on the track
00:37:09
and the track's here and here the two wheels are exactly balanced and it's nice and even
00:37:13
suppose accidentally it gets a bump or something and slides out this way
00:37:17
then this wheel is on a bigger circumference than this one
00:37:20
but they're on a solid shaft
00:37:22
so when it turns once around
00:37:24
it carries this wheel forward relative to the other
00:37:27
and steers the train back on the track
00:37:29
of course if it gets too far off on the other side it goes back and forth and it stays on the track
00:37:33
because the wheels are tapered and the flange is safety
00:37:37
well we had a lot of stuff like that that we had to learn you know
00:37:40
that would get straightened out before we could become full-fledged members of the fraternity
00:37:54
If I'm sitting next to a swimming pool and somebody dives in
00:37:59
and she's not too pretty, so I can think of something else
00:38:02
I think of the waves and things that have formed in the water
00:38:06
and when there's lot's of people that have dived in the pool, there's a very great choppiness of all these waves all over the water,
00:38:13
and to think that it's possible, maybe, that in those waves there a clue as to what's happening in the pool,
00:38:18
that some sort of insect or something with sufficient cleverness,
00:38:22
could sit in the corner of the pool and just be disturbed by the waves,
00:38:26
and by the nature of the irregularities and bumping of the waves have figured out
00:38:31
who jumped in, where and when and what's happening all over the pool.
00:38:36
And that's what we're doing when we're looking at something:
00:38:39
the light that comes out is waves
00:38:42
just like in the swimming pool, except in 3 dimensions
00:38:44
instead of 2 dimensions of the pool and it's going in all directions
00:38:48
and we have a 8'th of an inch black hole into which these things go,
00:38:53
which is particularly sensitive to parts of the wave that are coming in a particular direction
00:38:58
and it's not particularly sensitive when they're coming in at the wrong angle,
00:39:01
which we say is from the corner of our eye,
00:39:03
and if we want to get more information from the corner of our eye, we swivel this ball about so that the hole moves from place to place.
00:39:10
Then,
00:39:13
it's quite wonderful that we figure out so easy;
00:39:18
that's really because the light waves are easier and the waves in water are a little bit more complicated;
00:39:23
it would have been harder for the bug than for us, but it's the same idea,
00:39:26
to figure out what the thing is that we're looking at at a distance,
00:39:32
and it's really kind-of incredible because when I'm looking at you,
00:39:35
someone standing to my left can see somebody who's standing at my right;
00:39:39
that is, the light could be going right across this way, the waves are going this way,
00:39:43
the waves are going this way, the waves are going this way, it's just a complete network.
00:39:48
Now, it's easy to just think of them as arrows passing each other, but that's not the way it is,
00:39:52
because all of this is something shaking -it's called the electric field,
00:39:55
but we don't have to bother with what it is- it's just like the water height is going up and down.
00:39:59
So there's some quantity shaking about here
00:40:02
and the combination of motions that's so elaborate and complicated that the result is to produce an influence which makes me see you.
00:40:08
At the same time, completely undisturbed by the fact that there are influences that represent the other guy seeing him on this side.
00:40:16
So that there's this TREMENDOUS mess of waves all over in space which we call
00:40:24
which is the light bouncing around the room and going from one thing to the other,
00:40:28
because of course most of the room doesn't have 8'th inch black holes. It's not interested in that light,
00:40:34
but the light is there anyway, and it bounces off this, and it bounces off that,
00:40:38
and all this is going on, and yet we can sort it out with this instrument.
00:40:45
But beside all that, you see, those waves that I was talking about in the water,
00:40:49
maybe they're so big - some of them - and then there's slower swashes which are longer, and shorter.
00:40:54
Perhaps that animal is making it's study only using waves between this length and that length,
00:40:59
so it turns out that the eye is only using waves between this length and that length,
00:41:05
except those two lengths are 100,000'th of an inch - 100,000'th of an inch big,
00:41:13
and what about the slower swashes?
00:41:15
The waves that go more slowly, that have a longer distance from crest to trough.
00:41:20
Those represent heat. We feel those, but our eye doesn't see them focused very well, we don't in fact at all.
00:41:27
The shorter waves are blue, the longer waves are red. But when it gets longer than that then we call them infrared.
00:41:35
And all this is in there at the same time. That's the heat.
00:41:39
Pit viper that get down here in the desert, they have a very little thing that they can see longer waves
00:41:46
and pick up mice, which are radiating their heat in the longer waves
00:41:51
but their body heat by looking at them with this eye, which is the pit of the pit viper.
00:41:57
But we can't, we are not able to do that.
00:41:59
And then these waves get longer and longer, and all through the same space,
00:42:03
all these things are going on at the same time, so that in this space, there's not only my vision of you,
00:42:10
but information from Moscow Radio that's being broadcasted at present moment, and the seeing of somebody from Peru.
00:42:18
All the radio waves are just the same kind of waves, only they are longer waves.
00:42:22
And there's the radar, from the airplane which is looking at the ground to figure out where it is, which is coming to the room at the same time.
00:42:29
Plus X-rays, cosmic rays and all of these other things that are the same kind of waves,
00:42:33
EXACTLY the same kind of waves, but shorter, faster or longer, slower.
00:42:37
It is exactly the same thing.
00:42:39
So this big field, this - this area of irregular motions of this electric field, this vibration, contains this tremendous information,
00:42:50
and it's ALL REALLY there, that's what gets you.
00:42:54
If you don't believe it, then you pick a piece of wire and connect it to a box
00:43:01
and in the wire the electrons would be pushed back and forth by this electric field, swashing just at the right speed for the certain kind of long waves,
00:43:08
and you turn some knobs on the box to get the swashing just right, and you hear Radio Moscow!
00:43:13
Then you know that it was there. How else did it get there?
00:43:15
It was there all the time. It is only when you turn on the radio that you notice it.
00:43:20
But that all these things are going through the room at the same time which everybody knows,
00:43:25
but you gotta stop and think about it to really get the pleasure
00:43:29
about the complexity - the INCONCEIVABLE nature of nature.
00:43:43
When we were talking about the atoms, one of the trouble we have with the atoms is
00:43:46
that they are so tiny and it is so hard to imagine the scale.
00:43:50
The atoms are in size compared to an apple is the same scale as an apple is compared to the size of the earth.
00:43:58
That's kind of a hard think to take, and you have to go through all these things all the time
00:44:02
and people find these numbers inconceivable and I do too
00:44:06
And the only thing you do is just change your scale
00:44:08
you just think of small balls but you don't try to know exactly how small they are too often
00:44:13
or you get kind of a bit nutty, alright?
00:44:16
but in astronomy you have the same thing in reverse
00:44:20
because the distances to these stars are so enormous
00:44:23
You know that light goes so fast, and it only takes few seconds to go to the moon and back
00:44:28
or it goes around the earth in seven and a half times in a second
00:44:32
and it goes for years... two years, three years before it gets to the nearest other star that there is to us!
00:44:38
But all our stars are in nearby galaxies, a big mess of stars which is called a galaxy, a group
00:44:47
but our galaxy is (what is it) some hundred thousand light years, like 100 000 years
00:44:54
And then there's another patch of stars
00:44:56
It takes a million years for the light to get here going at this enormous rate
00:45:01
and you just go crazy trying to make too real that distance.
00:45:05
You have to do everything in proportion. That's easy
00:45:07
say that galaxies are little patches of stars and they're ten times as far apart as they are big
00:45:12
So that's an easy picture. But you just go to a different scale, that's easier
00:45:16
once in a while you try to come back to earth scale to discuss the galaxies, but it's kind of hard
00:45:23
The number of stars we see at night is only about five thousand.
00:45:28
but the number of stars in our galaxy, the telescope have shown when you improve the instruments
00:45:33
Oh! We look at a galaxy, we look at the stars, all the light that we see, the little tiny influence,
00:45:40
spread from the stars over this enormous distance of what three light-years for the nearest stars
00:45:44
on! on! on! this light from the star is spreading, the wavefront's getting wider and wider
00:45:49
weaker and weaker, weaker and weaker out into all of space
00:45:52
and finally the tiny fraction that comes in one square eighth of an inch little black hole
00:45:57
and does something to me so I know it's there!
00:46:01
Well to know a little bit more about, I'd rather gather a little more of this tiny fraction of the front of light
00:46:08
and so I make a big telescope which is a kind of funnel.
00:46:12
The light that comes over this big area-200 inches in cross-is very carefully organized
00:46:17
so it is all concentrated back so it can go through pupil.
00:46:20
Actually it's better to photograph, and nowadays they use photocells which are better instruments
00:46:25
but anyway the idea of a telescope is to focus the light from a bigger area into a smaller area
00:46:30
so that we see things that are weaker, less light
00:46:32
and in that way we find there's a very large number of stars in the galaxy.
00:46:37
There's so many that if you try to name them, one in a second, all of the stars in our galaxy
00:46:43
I don't mean all the stars in the universe just this galaxy here
00:46:47
it takes three thousand years! And yet that's not a very big number
00:46:51
Because if those stars were to drop one dollar bill on the earth
00:46:56
during a year each star dropping one dollar bill
00:46:59
they might take care of the deficit, which is suggested for the budget of the United States!
00:47:06
So you see what kind of numbers we have to deal with!
00:47:09
Anyway I think that the numbers are problems in astronomy, the size and numbers
00:47:14
the best thing to do is to relax and enjoy the tininess of us and the enormity of the rest of the universe
00:47:22
Of course, if you're feeling depressed by that, you can always look at it the other way
00:47:26
and think how big you are compared to the atoms and the parts of atoms then you're an enormous universe to those atoms
00:47:33
so you can sort of stand in the middle and enjoy everything both ways
00:47:38
But the great part of astronomy is the imagination that is necessary to guess what kind of structures
00:47:46
what kind of things can be happening to produce the light and the effect of the light of the stars that we do see
00:47:53
and I could take an example, a historical example
00:47:58
many times in science, by using imagination you imagine something
00:48:02
which could be according to all the known knowledge and the laws
00:48:06
and you don't know whether it is yet or not
00:48:09
And that's very interesting, there is a creative imagination you'd like to call it
00:48:13
not just imagining thing that are relatively easy, but something different
00:48:16
And to take an example of, a star as we understand it
00:48:20
ordinary stars like the Sun, which is just a big ball of gas, of hydrogen
00:48:24
that's burning up the hydrogen and so forth and it's an enormous mass of gas
00:48:28
and it's held together by gravity
00:48:31
you don't to always understand gravity as a curved space
00:48:34
good enough for the purpose that a force inversely square the distance
00:48:37
When the things are closer together, the force is stronger, and it pulls everything together
00:48:42
By the way that's why the world is round:
00:48:45
because the globe of earth is pulled together as much as possible
00:48:48
and if it had a great mountain and an irregularity like a bump
00:48:51
so it would be pulled in by gravity and it all gets smooth
00:48:54
Rocks aren't strong enough to hold a bump much bigger than a few miles
00:48:58
and Mount Everest is our biggest bump
00:49:00
But on the moon where the gravity is less, the bumps are higher; the mountains are bigger on the moon.
00:49:05
Anyway, to get back to the star, it's all held together by gravity
00:49:09
and it's got a nuclear fuel which we've haven't been talking about
00:49:14
that's burning up the hydrogen and generating energy which keeps things going
00:49:17
And after a while, it would use the fuel a lot
00:49:19
people began to think about what would happen then
00:49:22
and it would be possible to just be gas sort of hanging around held together by gravity but quiet
00:49:28
but another possibility was to think
00:49:31
if I push the stuff together closer, the gravity is stronger, would hold it together.
00:49:37
Well if you push a little bit together, the pressure increases
00:49:41
when you push the gas together, there are more atoms and they pound on it
00:49:44
so the pressure is higher but the gravity is stronger
00:49:47
and it turns out the pressure wins so it would just come out again
00:49:50
if you're pushing a star like that, it oscillates
00:49:53
and there are some stars that are oscillating and vibrating and so on
00:49:56
but it turns out if you keep on analyzing
00:49:59
you push it together very far to the incredible concentration
00:50:03
that the whole mass of the sun is down to the size of the earth or smaller
00:50:08
then it turns all the nuclear matter all the nuclei of the atoms are all stuck next to each other tight
00:50:15
Spaces where the electrons are all squashed out and it comes out
00:50:19
when you get to THAT far, the gravity is strong enough to overpower the pressure again
00:50:25
even though the pressure has got to be enormous, the gravity has to be even more enormous
00:50:30
and the thing will stay steady at a different size
00:50:32
and be nothing but a neutron, a nuclear matter, nothing solid, nuclear matter
00:50:39
and this possibility was worked out by Oppenheimer and Volkov, it's called a neutron star
00:50:46
And people waited to see if there were any such neutron stars for years
00:50:50
until recently they found these strange pulsars which emit flashes of radio waves later they found light
00:51:00
which can go 30 times a second for instance the fastest ones or maybe 10 times a second or one a second
00:51:07
And at first, that's very mysterious; you are used to stars being big and slow
00:51:12
how can anything in a star move in a thirtieth of a second?
00:51:15
Well these things are very small neutron stars and they’re spinning very fast.
00:51:21
For reason not yet understood, they are emitting a beam, a beam of radio waves
00:51:25
like a search light in an airport or something those things that go around boop boop boop
00:51:29
so we get the flashes tick tick tick, that fast
00:51:33
to imagine a star the mass of the sun, doing something, turning so fast 30 times a second
00:51:39
another one of these big numbers, hard to conceive imaginary things okay?
00:51:45
and the whole idea that there could be a star of such enormous density that a teaspoon would weigh so much
00:51:51
of the matter if you put it on the earth surface it is so heavy that that it will just plough right to the center of the earth!
00:51:57
and things like that, it took a lot of imagination:
00:52:01
it comes out the mathematics and the analysis of all this helps you to make sure you are not making a mistake
00:52:06
and it turns out that such a star is possible, and it turned out a little bit later they do exist
00:52:11
and that's a good example of how imagination is a useful thing
00:52:17
and produces a guessing ahead of time and how we make advances by using it
00:52:23
Besides, the very difficult thing of imagining all the things that might be up there to explain the things we see
00:52:30
in the case of astronomy, we have a large number of things we see
00:52:34
that we have not yet quite clearly got the imagination to see what it is that's producing them
00:52:41
Quasars are very powerful sources of light and radio waves from very great distances
00:52:47
and we see them because they are so bright.
00:52:50
The exact cause of their sources is gradually been recently understood
00:52:56
in terms of another nutty concept of imagination: the black hole
00:53:01
which is something that comes from following the logic of gravity of Einstein to its ultimate
00:53:09
working out the consequences in crazy circumstances
00:53:12
Suppose you had an amount of matter so great
00:53:16
that the gravity force is so much that even light trying to get out falls back
00:53:23
Nothing can go faster that light, and nothing could escape. You couldn't see it!
00:53:28
how would you get there? If you have a large amount of matter to start with, it could fall together
00:53:34
and get into this condition that no longer could the light come out.
00:53:37
So you would have this thing which continues to attract things to it
00:53:41
things would go in and nothing would come out. That is called the black hole.
00:53:46
and you say well how can a black hole which is absorbing everything make all this energy that we see
00:53:51
Is that an explanation of a quasar? Actually, it may well be
00:53:54
Because the things that are falling in don't go pluck in but go around, falling in by swirling
00:54:01
then as they are falling irregularly and so forth, and in the fast motions that it produces they go down this whirlpool
00:54:08
they generate a lot of energy and friction and so forth, and different kind of effects
00:54:12
magnetic and electric effects that could make the jets of matter that come out of the quasar and the radio galaxies
00:54:19
in ways that are not really understood.
00:54:22
We don't have a real picture why there are jets of radio waves, matter emitting radio waves in galaxies
00:54:30
there are galaxies which great jets coming out with big clouds of matter on each side which are emitting radio waves
00:54:37
so there's some kind of a source in there
00:54:39
it sort of gets wound up and shoots these jets of matter out with tremendous energy
00:54:45
And it's guessed that maybe it's a black hole somehow or other
00:54:50
and the somehow or other is the challenge of the imagination
00:54:54
Which has not yet been answered. by anybody, with any great confidence.
00:55:05
You ask me if an ordinary person, by studying hard, would get to be able to imagine these things, like I imagine
00:55:12
Of course! I was an ordinary person who had studied hard.
00:55:16
There are no miracle people.
00:55:18
It just happen they got interested in these things and they learned all these stuffs.
00:55:24
There are just people
00:55:25
There's no talent, special, miracle ability to understand quantum mechanics or a miracle ability to imagine electromagnetic fields
00:55:36
that comes without practicing and reading and learning and study
00:55:40
so if you say it take an ordinary person who's willing to devote a great deal of time
00:55:45
and study and work and thinking and mathematics and time, then he has become a scientist.
00:55:55
When I'm actually doing my own things
00:55:58
and working in a high, deep and esoteric stuff that I worry about
00:56:04
I don't think I can describe very well what it's like
00:56:10
First of all, it's like asking a centipede which leg comes after which
00:56:14
it happens quickly and I'm not exactly sure what flashes and stuff go in the head
00:56:19
But I know it's a crazy mixture of partial equations, partial solving in equations,
00:56:24
then having some sort of picture of what is happening that the equation is saying it's happening
00:56:29
but they're not that well separated as the words I'm using and it's a kind of a nut nutty thing
00:56:36
it's very hard to describe, and I don't know that it does any good to describe
00:56:40
And there's something that struck me, it's very curious:
00:56:45
I suspect that what goes on in every man's head might be very very different, the actual imagery or semi-imagery which comes
00:56:57
and when we are talking to each other at these high and complicated levels
00:57:00
and we think we are speaking very well, that we are communicating
00:57:06
but what we are really doing is having a some kind of big translation scheme going on
00:57:10
for translating what this fellow says into our images, which are very different.
00:57:15
I found that out because in the very lowest level I wouldn't go into much details but I got interested in...
00:57:25
Well I was doing some experiments and I was trying to figure out something about our time sense
00:57:31
and so what I would do is trying to count to a minute
00:57:35
actually say I'd count to 48 then it would be one minute
00:57:39
so I calibrate myself and I would count a minute in 48
00:57:42
think I was counting seconds but it's close enough
00:57:44
and then it turns out if you repeat that you can do very accurately
00:57:48
when you get to 48 or 47 or 49, not far off, you're very close to a minute.
00:57:54
And I was trying to find out what affected that time sense
00:57:57
and whether I could do anything at the same time I was counting
00:58:01
and I found that I could do many things I could, there were some things that not
00:58:08
For example, I had great difficulty…
00:58:10
I was in the university, I had to get my laundry ready, and I was putting the socks out
00:58:19
and I had to make a list "how many socks", there were something like 6 or 8 socks and I couldn't count them
00:58:24
because the counting machine was being used, and I couldn't count them
00:58:27
until I found that I could put them in a pattern and recognize the number
00:58:31
and so I learned a way after practicing
00:58:33
by which I could count the line of type in a newspaper and see them in groups
00:58:37
three, three, three, three, one that's a group of ten, three, three, three, one
00:58:40
without saying the numbers just seeing the groupings
00:58:42
I could therefore count the line of types I was practicing in the newspaper
00:58:46
the same time I was counting internally the seconds
00:58:49
so I could do this fantastic trick of saying
00:58:53
"forty-eight, that's one minute and there are sixty seven lines of type" you see!
00:58:58
It was quite wonderful and I discovered many things I could read while I was..
00:59:05
no, excuse me, yes, I could read perfectly alright while I was counting and get an idea of what it was about
00:59:14
But I couldn't speak, I couldn’t say anything.
00:59:17
Because of course I was sort of trying to speak to myself, inside, I would say "one, two, three" or sort of in the head.
00:59:24
Then I went down to the breakfast, and there was John Tukey was a mathematician at Princeton in the same time
00:59:33
and we had many discussions, and I was telling him about these experiments and what I could do
00:59:37
and he says "that's absurd!" he says
00:59:40
He said "I don't see why you have any difficulty talking whatsoever,
00:59:44
And I can't possibly believe that you could read"
00:59:47
so I couldn't believe all this but we calibrated him
00:59:50
it was 52 for him to get to 60 seconds or whatever I don't remember the numbers now
00:59:55
and then he said "alright, what do you want me to say?
00:59:58
Mary had a little lamb. I can speak about anything, blah blah blah, blah blah,
01:00:02
52! that's one minute". He was right. And I couldn't possibly do that
01:00:07
And he wanted me to read, because he couldn’t possibly believe it.
01:00:09
and then we compared note, and it turned out that when he thought of counting
01:00:13
what he did inside his head when he counted was he saw a tape with numbers it went "clink, clink clink"
01:00:20
the tape would change with numbers printed on it, he could see
01:00:23
well since it's sort of an optical system that he was using, and not voice.
01:00:28
He could speak as much as he wanted but if he had to read, then he couldn't look at his clock!
01:00:33
Whereas for me it was in the other way.
01:00:34
And that's where I discovered, at least in this very simple operation of counting
01:00:39
the great difference in what goes on in the head when people think they are doing the same thing
01:00:46
And so it struck me therefore, if that is already true at the most elementary level
01:00:51
That when we learn mathematics and Bessel functions, and the exponential and the electric field and all these things
01:00:59
that the imageries and the method by which we are storing it all and the way we think about it
01:01:05
could be really, if we get to each other's head, entirely different
01:01:09
And in fact, while somebody sometimes has a great deal of difficulty to understanding a point which you see as obvious, and vice versa
01:01:17
it's maybe because it's a little hard to translate what you just said into his particular framework and so on
01:01:22
Now I'm talking like a psychologist, and you know I know nothing about this!
01:01:29
Suppose that little things behaved very differently that anything that was big, anything that you're familiar with
01:01:39
because you see as the animal evolves and so on, as brain evolves
01:01:42
it gets used to handling the brain is designed for ordinary circumstances
01:01:49
but if the gut particles in the deep inner workings where by some other rules and some other characters
01:01:55
they behave differently they were very different than anything on a large scale
01:02:00
then there would some kind of difficulty in understanding and imagining reality.
01:02:05
And that difficulty, we are in.
01:02:09
The behavior of things on the small scale is so fantastic! It is so wonderfully different!
01:02:16
so marvelously different that ANYTHING that behaves on a large scale.
01:02:20
You said "electrons act like wave", no they don't exactly,
01:02:24
"they act like particles", no, they don't exactly,
01:02:26
"they act like a kind of a fog around the nucleus", no they don't exactly.
01:02:31
And if you want to get a clear, sharp picture of an atom, so that you can tell exactly how it's going to behave correctly
01:02:40
and have a good image in other words, really good image of reality
01:02:44
I don't know how to do it. Because that image has to be mathematic:
01:02:49
we have a mathematical expression, a strange mathematics, I don't understand how it is
01:02:53
but we can write mathematical expressions and calculate what the thing is going to do
01:02:59
without actually being able to picture it
01:03:02
It would something like a computer in which you put certain numbers in
01:03:05
and you have a formula for what time the car will arrive at different destination
01:03:09
and the thing does the arithmetic to figure out what time the car arrives at the different destinations
01:03:14
but cannot picture the car. It is just doing the arithmetic
01:03:18
So we know how to do the arithmetic, but we cannot picture the car
01:03:23
It's not a 100% because for certain approximate situations, certain kind of approximate pictures work
01:03:29
that it's simply a fog around the nucleus that when you squeeze it, it repels you
01:03:34
it's very good for understanding the stiffness of certain material
01:03:38
that it's a wave which does this and that is very good for some other phenomena alright
01:03:43
So when you're working with certain particular aspects of the behavior of atoms
01:03:48
for instance when I was talking about temperature and so forth, that it's just little balls
01:03:53
it's good enough and it gives a very nice picture of temperature
01:03:56
but if you ask more specific question and you get down to questions like
01:04:00
"how is that when you cool helium down, even to absolute zero where it's not supposed to be any motion
01:04:07
it's a perfect fluid and it has no resistance and it flows perfectly, and it isn't freezing"
01:04:13
Well if you want to get a picture of atoms as all of that in it, I can't do it
01:04:17
But I can explain why the helium behaves as it does, by taking my equations
01:04:23
and seeing that the consequences of them is that the helium would behave as it is observed to behave
01:04:28
So we know that we have the theory right, but we haven't got the pictures that would go with the theory
01:04:34
And it's that because we haven't caught on the right picture
01:04:40
or it's because there aren't any right pictures for people who have to make pictures out of things that are familiar to them
01:04:50
Well let's suppose it's the last one, that there's no right picture in terms of things that are familiar to them
01:04:56
Is it possible then to develop a familiarity with those things that are not familiar on hand, by studying
01:05:05
by learning the properties of atoms and quantum mechanics, by practicing with the equations
01:05:10
until it becomes a kind of second nature
01:05:12
just like it's a second nature to know that two balls came towards each other, they smash into bits
01:05:18
You don't say "the two balls when they come toward each other turn blue". You know what they do
01:05:24
So the question is whether you can get to know what things do without... better that we do today
01:05:32
as the generations develop, will they invent ways of teaching so that the new people will learn tricky ways in looking at things
01:05:43
and be so trained, so well trained, that they won't have our troubles, with the atom picturing.
01:05:52
There's still a school of thought that cannot believe that the atomic behaviors is so different than large scale behaviors
01:06:02
I think that's a deep prejudice, it's a prejudice of being so used to large scale behaviors
01:06:06
and they're always seeking to find to waiting for the day that we discover
01:06:11
underneath the quantum mechanics there's some mundane, ordinary balls hitting or particles moving and so on
01:06:20
I think they're gonna be defeated
01:06:22
I think Nature's imagination is so much greater than man's, she's never gonna let us relax!
