Class:
Informatics, Computing, and the Future

Instructor:
Dan Berleant

Transcriber:
Brooke Yu

Date:
Tuesday, February 26, 2013

Professor: Okie doke.
So did anyone make it to the research internship lunch thing this
afternoon?

Male
Student: I wanted to, but I couldn't
make it.

Professor: Well, if you're interested in it still, just
send the head of the program an email.
Alright, and there's a homework due today. Any questions about it? More work on the term project- process some
of the stuff we talked about with TRIZ, and the video we watched.

I notice a
number of people are not quite up to date on their homeworks, so it's not too
late to always catch up. Just because
you didn't get to one doesn't mean you shouldn't go on to the next one. See me after class if you are concerned. The homeworks are not intended to be very
difficult, so I strongly encourage you to do your best.

Any questions
on the homework? Alright. So let's go back and continue talking about
spoil sports of the prediction game.
What I mean by a spoil sport is this- we'd like to be able to predict
the future, but the problem is you can't, and it's intrinsic that you can't for
several reasons, and those are what I call the spoil sports of the prediction
game.

Do you
remember what the observe effect is?

Male
Student: If something is observed, then
it changes the outcome of the event.

Professor: Exactly.
Do know something about the world, you have to observe it, but by
observing it you change it. So it's kind
of a spoil sport of the prediction game.

But maybe if
you observe it gently you don't have to change it much and you can predict to
some degree, and that's very true, but you run into other spoil sports like the
butterfly effect.

So let's talk
about some of these.

Here's the
observer effect [On board.]

This is the
Heisenberg uncertainty principle named after Heisenberg, an early
physicist. He was a famous physicist of
modern times, but he's dead. Certainly
the ancient Greeks had some philosophy on this, but modern physics didn't start
until around the time of Newton.

He was way
before Heisenberg, but he [Heisenberg] came up with the uncertainty
principle. We'll look at a video
soon. It says you can't know both the
position and the velocity of a particle, so you might know how fast it's going,
but you don't know where it is, or vice versa.

I read an
example the other day- I don't know if I have the reference to this, but it's
an interesting way to think about this principle.

Say you want
to take a snapshot of a moving object- a ball flying through the air. If you take a picture of a moving object, you
get a track, right? Do you know about
that?

The shutter
of the camera opens for a while, then closes.
During that period of time, whatever you're taking a picture of may be
moving and you'll get a streak on your picture.

That's why if
you want to take a good picture, you tell the person not to move. Smile first, then hold it until the click is
over.

If the object
is moving and you take a picture of it, then you don't know what the location
is at that point.

The length of
the smudge tells you how fast it's going by doing some calculations.

So there's an
example of how you can figure out how fast something was going, but where it
was.

Say you get a
high speed camera and you use bright light and make the shutter go really
fast. So the shutter can open and close
really fast and it doesn't matter if the object is moving- the image will still
be pretty sharp. So you know where the
object is, but you don't know how fast it's going.

So that's an
example- an analogy of the Heisenberg uncertainty period- the better the know
the position, the worse you know the velocity.
You can't get both at the same time.
It also works as a physical principle.

Let's look at
a little video. It gives you the
equation

It's pretty
simple, considering the advanced physics.

It's the idea
you can never know where the electron is.

The more you
know about location, the less you know about momentum.

Here's the
equation that relates this [On board.]

Alright,
delta x is your position. How well do
you know where the electron is? This is
the mass of the object times speed. And
it's greater than or equal to h, which is Plank's constant, over 4pi. If you do the math, you'll discover that the
value for delta x is usually about a meter in in electron in an atom.

Now why is
that a problem? A meter is like 3 feet,
right? And 3 feet is much bigger than an
atom. The ultimate answer is it feels
like a joke. If you go to a hotel and it
has a sign that says "George bush slept Here" well, they have
"Heisenberg slept here" because you never know!

So that's
probably as clear as mud, frankly. You
can never know the exact position of an electron and if you did, it would have
moved.

Professor: Okay, I just want to show you one thing about
this before I go on to the next thing.

Okay, so I
was saying, you now, position and velocity are the trade off. But they're talking about momentum which is
mass times velocity.

In fact, it
is momentum, but since the mass is usually not variable, if you pull this
constant, then the uncertainty is in the velocity not the mass. Normally, you know what the mass is, so you
could just think of it as uncertainty in velocity.

So that's the
math of it.

And they talk
about electrons, but it applies to all particles- protons, neutrons, orange
folders. But the mass of the orange
folder is much greater than that of an electron, so it makes the uncertainty
less. When you're dealing with an object
that's of normal size, these physics effects become very tiny. If it's an electron- really tiny and fast-
the uncertainty is a meter. It's
spinning around the atom, but you don't know where it is within a meter. It could spin a lot in that time.

Here's
another video. This one talks about
photons or light particles, okay? The
interesting thing about photons or light particles is that they have a known
speed.

So the
Heisenberg uncertainty shows up in a slightly different way, as you'll
see.

Heisenberg's
principle is very strange. I call it
bizarre.

Professor: Let's try this one. Ooh, now we're in trouble. We'll have to live with the flashing.

_________

Frankly
speaking, I call it bizarre. But you can
see it at work. Suppose I have a laser
beam for my light source. I make an
opening- a vertical slit. And here goes
the laser beam right through the slit.
What do I see? You see exactly
what you predict. Now I'll make the slit
narrower and narrower.

You'll cut
off the edges of the circle and the spot gets narrower. But now you come to the point that this
narrow slit is only 1/100 of an inch wide.
Now you know so precisely in the horizontal direction where it is, that
as it emerges from the slit, the light is no longer determined. So now it will get wider. What am I doing? I'm making the slit narrower and narrower,
and the beam becomes wider and wider and wider.

Now that is
the way the world works.

I want to try
to explain that little bit.

So it was
kind of a cool experiment, but it's trick to understand. Does anyone remember what velocity is?

What is
velocity?

Male
Student: It's related to kinetic
energy?

Professor: Anybody remember anything else?

Male
Student: Speed and direction?

Professor: Right.
Velocity is speed and direction.

So he didn't
tell you that in the video, but what's going on with the light. It's really fast. It can go to the moon in less than a
second. It takes 8 minutes for the sun's
light to get to the earth.

So if we have
uncertainty in the velocity. We know how
fast it is, so the uncertainty is in the direction. When you send the light through the narrow
slit, the slit is trying to make the direction.... it specifies the
direction. So here's the slit, and as it
gets narrow over here, it constrains where the photons move. The uncertainty shows up in the direction-
the closer I try to specify the direction, the more the direction actually
becomes spread out.

It goes from
a spot to a bar and spreads out. They
try to specify direction with the slit, and when they do that, the direction
becomes less certain and the photons land across a range and you get a bar of
light.

In the video,
they showed a device that adjusts the slit, but you don't need that. You can do it with a piece of plastic. Let's take a look.

I want to
turn off this thing temporarily.

So here's the
plastic, and I'm going to shine the laser through it. Can you see the plastic has a V-shape cut in
it? If I move the laser through this,
it'll do what the video showed. When I
move it closer, the dot will spread out.
So be patient with me.

It will
demonstrate principal using ordinary tools.

So I'll move
the beam closer to the plastic. See
that?

This is just
getting close to where the v ends. You
all saw that, right? It still works, but
it's not as good up close.

So an
ordinary laser pointer- it doesn't specify direction very well. Instead of getting an oblong dot, you'd get a
pinpoint. If I only let a few through,
it just spreads out.

Because you
can't specify the exact direction.

Okay, turn
this thing back on.

It applies to
electrons. Photons are weird because
they're particles of light but the particles of light are strange. There's some physics I don't understand
there. I love physics even though I
don't understand it.

So what did I
do? I did what he did in the video but
with a laser pointer and some plastic.

So anyway,
the uncertainty principle says you can't, at the same time, know both position
and momentum. By momentum, I mean mass
times velocity. Mass is usually constat,
so the velocity is what is unknown.

In fact, if
you want to ask the ratio of uncertainty, they equal this number, which is a
constant. [On board.]

This numbers
says that the variation of uncertainty- the uncertainty in position times the
momentum have to equal a positive number.

Planck is
also a modern physicist.

Here it
is. You know about delta, right? You know what that is in some of your
classes? What does delta mean?

Male
Student: Change.

Professor: Right.
Here, it's uncertainty.

Male
Student: Rate of change?

Professor: Well, they use the term rate in
calculus. In this case, the delta means
a change.

And when you
divide a change by another change you get a rate.

The
uncertainty of one in position times the uncertainty in momentum can't be
0. You'd like the uncertainty in both to
be 0, but it's not, so we can't predict the future. That's why the Heisnberg effect is a spoil
sport of the prediction game.

So there are
some other things I wanted to say on that.
Normally we focus on position and velocity than in momentum, because the
mass is usually not in doubt. I mean, we
know about electrons pretty well and we know what their mass is.

Okay, so you
know, here's the theory. So what if we
don't know the position and velocity.
Would that even allow us to predict the future? Let's see.
If you know the position and velocity of every pool or billiard balls-
they're all the same size, they're very round.
If you know the position and velocity of every ball on the table, you
should be able to predict how it's going to pan out.

How many
numbers are needed to describe the position of a single pool ball?

Here's a
table. Here's a ball. How many numbers do you need to describe
where it is on the table?

Male
Student: x and y?

Professor: x and y.
Alright, let's try it. It's 17
inches from the left hand edge, and 19 inches from the bottom edge.

And we can
call this x and y. Let's say it's 17
inches from this side, and 19 from that side.
Does that tell where it is?

Male
Student: Unless you wanted to
incorporate height.

Professor: Okay, that's the next dimension, but the pool
table lets us just work in 2D. I'm
reading a physics book right now and the author describes how different
physicists think of the shape of the universe- he says they can't picture the
3D, so they picture it in 2D but they use equations and math to extend it to
the third dimension

So now we
know the position with 2 numbers. If it
was in 3 dimensions, we could add height.

So two
numbers tell where the thing. Exactly,
and 3 dimensions 3 numbers. 4
dimensions, 4 numbers. 1 dimension, 1
number.

Okay, so how
man numbers needed to describe position?
It depends on the dimensions.

We can do
that for all the balls. Okay?

In this case
we'd need 8 numbers, but that doesn't tell us enough about the pool table to
know what's going to happen. We have to
know how fast they're going.

So how many
numbers does it take to describe how fast one ball is going? Or the velocity- speed and direction
together.

Any
guesses?

Well? How about another two? Because if it's rolling this way, okay, then
it's going a certain speed in this direction and a certain speed in that
direction. It's going 10 miles an hour
in this direction, but that's the same as say it's go 5 in the other
direction.

Because it
turns out you could have a triangle and the numbers work out that way.

Does that
make sense? If you want to say how fast
it's going in this direction, you can describe how fast it's going both ways at
once.

You can tell
how fast and in what direction it's going with two numbers

The side to
side motion and the up and down motion.

So in every
ball, you can tell where it is and how fast it's going with four numbers in
2D.

In 2D, how
many numbers for this? 3

How many for
velocity. It has to be another three
because if it's going this way- I can say how fast it's going this way at the
same time I describe how fast it's going in other directions.

So this
really says that on a billiard table you can describe everything about it in
principle with 4 numbers per object. In
the 6 dimensional world, you can use 6 numbers.
If you have those 6 numbers for every particle, you can simulate how the
atoms will bounce off each other, and if you do that you can figure out the
future.

You can
figure out where everything is going to be.

So here's
another example of that in 2 dimensions.

So I'm going
to use a marker on this a little bit.

This particle
is 1, 2, 3.7 that way, and 3 that way.

So (3.7,
3). For velocity, I sort of graphically
describe it using an arrow and I show the direction and put the speed which is
2 whatever's/second, say.

Say it's
going in the upward direction, say 3 per second.

So we have a-
the four numbers that describe this particle exactly are the two position
numbers, which were 3.7 and 3, and the two velocity numbers which were 2 and 3,
and that describes everything there is to know about this particular ball.

And in 3
dimensions I just use 6 numbers instead of 4.

So you need 6
numbers for every object. I didn't talk
about mass, so you really need 7 to include mass. If you knew position, mass, and velocity of
every object, you could predict the future.

But you can't
get all of those numbers with full accuracy because of the uncertainty
effect.

The better
you know velocity, the worse you know position.

There's also
the observer effect, where even if you measured the velocity, you would change
it.

So that's two
spoil sports so far.

Higher
accuracy for one do those things means lower accuracy for the other.

[Teacher
reading: [On board.]

What if you
could control both? You can't. You can control them just enough to predict
the future as well as you need to.
You're a really good pool player.
You know light shining on the billiard balls won't make much of an
effect, and you're good at judging speeds and velocities, and the Heisenberg
effect is pretty small on the pool table, so that means you could become a
pretty good pool player.

But, just like
a confident pool player, you can only go so far. No matter how much you look at the table,
you're limited. You can only project the
future up to a certain degree.

That's
because there's several other wet blankets of the prediction game. One of those is quantum tunneling, which is
weird.

This is spoil
sport number 3. So what is quantum
tunneling mean? Well, according to this
advance physics theory, quantum physics, objects don't really have a specific
location where we normally think of them.

They're
actually smeared over a space, okay? And
they exist- they don't own... they're not at a specific point. They're smeared over space and they only seem
to be at a particular point when you observe them.

Remember
someone said that if a tree falls in a forest is there a sound? Maybe not.
If you don't observe an object, you can't know where it is. It's smeared over space. And if you do observe it, it'll appear in
that space in which they exist with some probability

This leads to
some really weird things. Here's an
example. If an object is very near a
barrier, okay, and the space over which it's smeared is large, it might be over
the barrier.

If you
observe it ,

[Teacher
reading: [On board.]

It just
existed with some probability in front of the barrier and some probability in
front of the barrier.

It's weird,
isn't it? And it applies to billiard
balls too, but not in an observable way.

In that
sense, quantum tunneling gives us this probability [On board.]

So if you
observe it on the wrong side of the barrier, it's gone through without making a
hole in it, and you have quantum tunneling.

Here's video
about that.

Some of us
were taught in high school that the electron rotates around the nucleus. There's an uncertainty to the very
small. No one can tell exactly where
something is. We can visualize this with
a probability cloud.

[On
board.]

Professor: Alright.
Here's another example of quantum tunneling. This is not an example of something- not
tunneling through a physical barrier.

You make the
pencil tip really sharp and then you flatten it a tiny bit. We'll say the flat spot is only three atoms
on that flat spot, but you're looking at the edge of the pencil and there are
three atoms- if it's a flat triangle, it could balance on the point. So let's get a pencil and sharpen it like
that on the point.

[Teacher
reading: [On board.]

The pencil is
actually smeared a little bit in space because no object has a specific
location. If you smear the pencil a
little bit, there's a probability that it won't be standing upright. It might be like this or like this.

If it is like
one of these then it will fall.

And indeed,
since the smearing is symmetric- if the pencil falls it could fall in any
direction. So you think it's balanced,
but after a while the smearing causes it to tip a little bit and it falls.

Well, it
turns out that if we were to make a pencil with such a tiny flat spot, and you
balanced it, it would be stable for a long time.

My
recollection is one pencil would last a month before it fell over by
itself. Oh, no. I think it was a lot of pencils. We'll see.

You could get
a bunch of pencils. You make an array of
1000 pencils by 1000 pencils. This room
would certainly hold those. They all
have a tiny flat spot on the tip.

In about 1
month sitting here, if we waited a month, one of the pencils would still fall
over because it's smeared.

Okay? Of course, once it falls it will hit
neighboring pencils and they'll all fall.

They've
actually done that calculation.

I don't
remember what it was a caution for physics teachers, but they liked to talk
about this pencil example.

So that's
quantum tunneling, and they actually use quantum tunneling in modern
electronics and so on. It also explains
why the sun shines because I guess the hydrogen nuclei have to tunnel to turn
into helium atoms.

Questions
about quantum tunneling? Thoughts?

It is
weird.

Okay, but
maybe we can live with that. A month is
a long time to store your pencil. So
maybe we can control all of these effects enough so that we can predict, but
unfortunately there are still troubles.

The next
trouble is spoil sport number four, and that's called the butterfly
effect.

The butterfly
effect may be a little tiny bit more something that you might have thought
about or noticed. I remember a couple
people have seen the movie the butterly effect.

So what's the
butterfly effect?

Male
Student: It's been a while.

Professor: Well, it has to do with butterflies.

Male
Student: Oh, the flap of the butterfly
wings can affect hurricanes.

Professor: Right.
The puffs of air from the butterfly wings eventually affect hurricane
travel.

You can never
predict which flap will make the hurricane go which way.

That's
actually been proven in weather and meteorology that weather is highly, you
know- small changes magnify over time.
You can't predict how they will, but they do. The person who discovered the butterfly
effect was a meteorologist.

Okay, so [On
board.]

The effects
tend to magnify over time, and at some time the paths of hurricanes will be
changed by those flaps. In a couple of
years, there will be a hurricane, so let's change where it goes. Don't blame me if it goes to the wrong
place.

I mean,
probably I really did change it. But
someone just coughed, so that changes it back

Male
Student: But it's contained in the
building, isn't it?

Professor: Yeah, but there are drafts, so it might slip
out.

Male
Student: So we're probably all mass
murderers in some ways.

Professor: Or maybe we've saved lives too. Here's a video showing the butterfly effect
in action on a physical system that's not subatomic particles.

It's called
the lorenz water wheel. He didn't
discover the butterfly effect though. He
designed a water wheel to demonstrate the concept though.

See, it's
made from a bicycle wheel.

So let's talk
about what's going on here. You have a
bicycle wheel with little buckets attached to it. Each bucket has a drain pipe and then there's
this water flow that drips water into the bucket. So you can see sort of what happens is that
which side the wheel turns is adjusted by the water. Water is always flowing in and out of the
buckets, but you can't predict which way it will turn.

The reason
you can't predict which direction it's going to be turning is because a little
tiny bit of water more in one bucket changes how much water drips into other
buckets, and that expands over time, so a little change here and there makes the
whole direction change later.

Of you wait
several seconds, the amount of time it rotates changes drastically. It seem random, you know?

Because you
can't predict

That is one
of the spoil sports of the prediction game.
Let's look at some different water wheels. They're all, in principle, similar, but there
are different mechanisms.

Here's a
double wheel. You can see the water is
dripping in and you can see how the wheel is unpredictably spinning in
different direction in different speeds.
This one should reverse at some point.

I think this
is made from a bicycle wheel too. Let's
look at one more.

There it
goes.

If you wanted
to see some of these at home, just go to youtube and type in lorenz water
wheel.

And there's
zillions of them! Wheel, it's about 54
results. Some are better than
others.

Some are made
with bicycle wheels, some are not.

That may not
be a lorenz wheel. I don't think it was. I think it was just an ordinary water
wheel. But this is a chaotic pattern
wheel. Let's take a look.

Here's one
not made with a bicycle wheel.

Alright.

So if you
wanted to make one of these for your project for this course, that would be
okay.

Okay, so
let's see what Lorenz says about this.

Actually,
this is what he wrote.

His name was
Edward Lorenz. Read this [On
board.]

Professor: Okay, so what he's really saying- right here-
it can't be done

So, you know,
how does that affect various things you might want to predict? We think about things like "when will
flying cars be typcially Used?" If
you mention it to someone, that person may tell someone else, and eventually
the effect of you saying it could translate into having flying cars a few years
sooner or later than it otherwise would have happened.

I'm trying to
think of any other things like that. If
you say something to someone, it might affect their mood, which might make them
miss class and not turn in their homework, which affects their grade.

You know that
fable about the nail in the shoe, which caused a problem in the horse, which
caused a problem with the battle, and so the war was lost. Heard anything like that? I wish I knew the actual.

We have five
minutes left and I don't want to start another one, so I want to see if I can
find that. Here it is.

Male
Student: So it's sort of like a chain
reaction.

Professor: Yeah, and an expanding one.

Male
Student: Because one thing causes
something else to be in conflict.

Professor: Mmhm.
Her's a thought. Suppose you've
been falling behind in your homework in this class. If you spend five minutes getting started
tonight, one thing will lead to another and you might end up on the dean's
list.

Okay. Well, there's a few more spoil sports- 3
more. And we'll talk about those next
time.

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