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PROFESSOR: OK, OK.

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Settle down, settle down.

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00:00:25,810 --> 00:00:26,310
All right.

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00:00:26,310 --> 00:00:28,480
Today is the last lecture.

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00:00:33,050 --> 00:00:34,240
You think you're happy?

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00:00:34,240 --> 00:00:36,780
I'm happy.

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00:00:36,780 --> 00:00:40,700
So what I'm going to do, I'm
going to teach for a little

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00:00:40,700 --> 00:00:43,890
bit, wrap it up, and then I've
got some comments about the

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00:00:43,890 --> 00:00:47,070
final exam, and then some
personal observations,

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00:00:47,070 --> 00:00:49,120
reflections on the class.

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00:00:49,120 --> 00:00:53,290
So of course, the main
announcement is the upcoming

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00:00:53,290 --> 00:00:56,450
celebration of celebrations,
a week from yesterday.

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00:00:56,450 --> 00:00:58,860
The final exam will
be Tuesday, 15

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00:00:58,860 --> 00:01:01,390
December, 9:00 to noon.

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00:01:01,390 --> 00:01:04,140
I know 9:00 a.m. is kind of
early for some of you.

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00:01:04,140 --> 00:01:05,460
Use the buddy system.

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00:01:05,460 --> 00:01:08,010
Get to that room on time.

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00:01:08,010 --> 00:01:11,030
9:00 to noon in the Johnson
Athletic Center.

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00:01:11,030 --> 00:01:14,880
I'll have office hours on
Monday, 3:00 to 5:00, and

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00:01:14,880 --> 00:01:15,940
Hilary will find a room.

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00:01:15,940 --> 00:01:18,950
We'll post it, and you can
swing by, if you want.

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00:01:21,710 --> 00:01:24,510
I guess the other thing I should
say is just a reminder

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00:01:24,510 --> 00:01:26,010
about the course evals.

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00:01:26,010 --> 00:01:30,250
Please take a few minutes and
fill out the course evals, if

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00:01:30,250 --> 00:01:33,600
not for me and for your
successors, but certainly for

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00:01:33,600 --> 00:01:36,570
our TAs, so that I can write
nice things about them when

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00:01:36,570 --> 00:01:39,070
the time comes.

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00:01:39,070 --> 00:01:42,150
So last day we looked at
binary phase diagrams.

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00:01:42,150 --> 00:01:44,560
And we looked at two
different types of

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00:01:44,560 --> 00:01:45,910
binary phase diagrams.

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00:01:45,910 --> 00:01:49,190
Type one, which is the
lenticular, and type two,

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00:01:49,190 --> 00:01:53,100
which is synclinal, and in both
instances, we came upon

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00:01:53,100 --> 00:01:57,410
two-phase regimes, and when p
equals 2, that causes you to

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00:01:57,410 --> 00:02:01,200
start thinking along the lines
of phase separation.

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00:02:01,200 --> 00:02:04,840
Phase separation then
invokes a tie line.

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00:02:04,840 --> 00:02:07,910
The tie line tells you the
composition of the two phases

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00:02:07,910 --> 00:02:10,920
present, and the lever rule
tells you the relative

45
00:02:10,920 --> 00:02:13,510
quantities, the relative
amounts, of

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00:02:13,510 --> 00:02:15,740
the two phases present.

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00:02:15,740 --> 00:02:19,290
What I want to do today is talk
about the last type of

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00:02:19,290 --> 00:02:23,290
phase diagram that we'll speak
about in 3091, and that's

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00:02:23,290 --> 00:02:25,220
called type three.

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00:02:25,220 --> 00:02:27,000
I came up with these
very original,

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00:02:27,000 --> 00:02:28,860
easy to remember labels.

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00:02:28,860 --> 00:02:29,600
So type three.

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00:02:29,600 --> 00:02:34,870
What characterizes type
three phase diagrams?

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00:02:34,870 --> 00:02:43,980
Well, we have partial solubility
of A and B. We're

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00:02:43,980 --> 00:02:44,700
doing all of this.

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00:02:44,700 --> 00:02:47,950
A is one of the components, and
B is the other component.

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00:02:47,950 --> 00:02:51,600
So partial solubility of A and
B, and change of state.

58
00:02:55,550 --> 00:03:02,730
And the result of this set of
characteristics is freezing

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00:03:02,730 --> 00:03:04,510
point depression of
both components.

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00:03:14,240 --> 00:03:20,570
And that's different from the
situation in type one.

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00:03:20,570 --> 00:03:27,950
In type one, you see, if we
have B on the right, then

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00:03:27,950 --> 00:03:31,980
adding at A to B, if this is
pure B over here, and this is

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00:03:31,980 --> 00:03:36,270
pure A over here, adding A
to B causes the freezing

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00:03:36,270 --> 00:03:37,510
point of B to fall.

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00:03:37,510 --> 00:03:41,790
But adding B to A causes the
freezing point of A to rise.

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00:03:41,790 --> 00:03:44,870
In this type three, we're going
to have freezing point

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00:03:44,870 --> 00:03:49,820
depression of both B and A.
That's the difference between

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00:03:49,820 --> 00:03:52,780
the type one and type three.

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00:03:52,780 --> 00:03:55,970
And actually, I'm going
to approach this by a

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00:03:55,970 --> 00:03:58,230
hybridization of sorts.

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00:03:58,230 --> 00:04:02,260
So I'm going to consider
type three a hybrid.

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00:04:02,260 --> 00:04:08,910
It's a hybrid diagram of the
lens and the syncline.

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00:04:08,910 --> 00:04:14,400
I'm going to blend the lens and
the syncline, and show you

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00:04:14,400 --> 00:04:16,250
how to do that.

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00:04:16,250 --> 00:04:19,470
So let me get one of those
up here, so that

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00:04:19,470 --> 00:04:21,970
we can look at it.

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00:04:21,970 --> 00:04:23,990
So what I'm going to do
here, this is a great

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00:04:23,990 --> 00:04:24,990
diagram to look at.

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00:04:24,990 --> 00:04:26,110
It's gold nickel.

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00:04:26,110 --> 00:04:29,340
And at the top, we have a type
one, and at the bottom, we

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00:04:29,340 --> 00:04:30,220
have a type two.

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00:04:30,220 --> 00:04:32,460
And what I'm going to do, is
I'm going to mix them.

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00:04:32,460 --> 00:04:33,690
I'm going to hybridize them.

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00:04:33,690 --> 00:04:35,710
I'm going to bring this
bottom one up and have

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00:04:35,710 --> 00:04:38,650
it touch the lens.

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00:04:38,650 --> 00:04:41,886
And so we get is something
that looks like this.

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00:04:41,886 --> 00:04:46,690
We'll plot temperature
versus composition.

88
00:04:46,690 --> 00:04:47,450
Left--

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00:04:47,450 --> 00:04:48,960
so here's temperature.

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00:04:48,960 --> 00:04:50,140
Composition.

91
00:04:50,140 --> 00:04:54,450
On the left I have pure A and
on the right I have pure B.

92
00:04:54,450 --> 00:05:00,540
And we'll start here with the
melting point of pure B. And

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00:05:00,540 --> 00:05:05,400
when I add A to B, I'm going to
get the depression that we

94
00:05:05,400 --> 00:05:07,420
see in the type one diagram.

95
00:05:07,420 --> 00:05:11,820
We want to start off like this,
and use everything we've

96
00:05:11,820 --> 00:05:12,910
learned up until now.

97
00:05:12,910 --> 00:05:15,640
So up here, we have
all liquid.

98
00:05:15,640 --> 00:05:17,430
This is all liquid.

99
00:05:17,430 --> 00:05:20,770
And over here, this is
a solid solution.

100
00:05:20,770 --> 00:05:23,560
This is pure B, and this
is B that has a

101
00:05:23,560 --> 00:05:24,980
little bit of A in it.

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00:05:24,980 --> 00:05:27,190
So we're going to use the old
metallurgical definition and

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00:05:27,190 --> 00:05:28,570
call this beta.

104
00:05:28,570 --> 00:05:34,940
Beta meaning, beta is a solution
of A and B, but it's

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00:05:34,940 --> 00:05:37,980
very rich in B. It's almost pure
B. So I'm going to call

106
00:05:37,980 --> 00:05:46,700
this a B-rich solid solution
of A and B.

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00:05:46,700 --> 00:05:50,490
And we know from last day, you
can't go from p equals 1,

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00:05:50,490 --> 00:05:53,380
let's get those labels up here,
you can't go from p

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00:05:53,380 --> 00:05:56,870
equals 1 to another p equals
1 without going

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00:05:56,870 --> 00:05:58,080
through a p equals 2.

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00:05:58,080 --> 00:06:02,610
So this is single phase and this
is single phase, and that

112
00:06:02,610 --> 00:06:06,410
means this one here must
be two phrase.

113
00:06:06,410 --> 00:06:07,730
And what are the two phases?

114
00:06:07,730 --> 00:06:10,490
The two phases are the phases
that are on either side.

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00:06:10,490 --> 00:06:13,630
So this must be liquid
plus beta in here.

116
00:06:13,630 --> 00:06:15,400
And that means--

117
00:06:15,400 --> 00:06:21,610
phase rule-- p equals 2,
tie line, lever rule.

118
00:06:21,610 --> 00:06:24,000
So that's what's going
on in there.

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00:06:24,000 --> 00:06:27,020
And then the difference is,
on this side, if this is t

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00:06:27,020 --> 00:06:31,140
melting point of A we're going
to start off with the same

121
00:06:31,140 --> 00:06:32,380
concept here.

122
00:06:32,380 --> 00:06:35,090
That we're going to get freezing
point depression of

123
00:06:35,090 --> 00:06:36,620
A, as well.

124
00:06:36,620 --> 00:06:38,500
So we'll have the liquid.

125
00:06:38,500 --> 00:06:41,580
Over here we'll have
an A-rich solution.

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00:06:41,580 --> 00:06:43,300
So then I'm going to
call that alpha.

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00:06:43,300 --> 00:06:51,140
So alpha is an A-rich solid
solution of A and B. And then

128
00:06:51,140 --> 00:06:53,080
that must mean that in
between here, we

129
00:06:53,080 --> 00:06:56,460
have liquid plus alpha.

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00:06:56,460 --> 00:06:57,865
And these keep going.

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00:06:57,865 --> 00:07:00,640
And in addition, down at the
low end, I'm going to start

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00:07:00,640 --> 00:07:03,480
with a syncline.

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00:07:03,480 --> 00:07:06,220
I'm going to start with a
syncline, coming up like so,

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00:07:06,220 --> 00:07:07,650
and coming up like so.

135
00:07:07,650 --> 00:07:10,550
See what I'm doing?

136
00:07:10,550 --> 00:07:13,610
I'm taking the lens.

137
00:07:13,610 --> 00:07:15,260
I'm going to meet
the syncline.

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00:07:15,260 --> 00:07:15,990
So what's here?

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00:07:15,990 --> 00:07:18,160
This is alpha, this is beta.

140
00:07:18,160 --> 00:07:20,660
What's inside the syncline?

141
00:07:20,660 --> 00:07:24,780
This is miscibility gap, so
this is alpha plus beta.

142
00:07:24,780 --> 00:07:26,860
So let's keep the phase
labeling here.

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00:07:26,860 --> 00:07:28,910
This is p equals 2.

144
00:07:28,910 --> 00:07:33,850
And look at how things have
worked out so nicely.

145
00:07:33,850 --> 00:07:40,040
p equals 1, p equals 2, p equals
1, p equals 2, p equals

146
00:07:40,040 --> 00:07:42,240
1, p equals 2.

147
00:07:42,240 --> 00:07:42,895
So nice.

148
00:07:42,895 --> 00:07:45,420
And what happens when
all this intersects?

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00:07:45,420 --> 00:07:47,790
It intersects like so.

150
00:07:47,790 --> 00:07:50,790
Try to do this, stretch
it a little bit.

151
00:07:50,790 --> 00:07:54,390
So these two lines connect.

152
00:07:54,390 --> 00:07:56,370
They cross at this point.

153
00:07:56,370 --> 00:07:58,000
They touch at this point,
the don't cross.

154
00:07:58,000 --> 00:07:59,100
They just touch.

155
00:07:59,100 --> 00:08:04,430
And then this arc comes up like
so, this comes down like

156
00:08:04,430 --> 00:08:09,923
so, and now we have a line
across here, and this comes

157
00:08:09,923 --> 00:08:11,400
down like so.

158
00:08:11,400 --> 00:08:11,820
OK?

159
00:08:11,820 --> 00:08:18,970
So the syncline stops at this
value, which is the minimum

160
00:08:18,970 --> 00:08:22,330
temperature dictated by
the two liquidus.

161
00:08:22,330 --> 00:08:24,900
We have a liquidus here and a
liquidus here, and this gets

162
00:08:24,900 --> 00:08:27,060
you down to the lowest
temperature.

163
00:08:27,060 --> 00:08:32,090
And let's look at the phase mix
going in this direction.

164
00:08:32,090 --> 00:08:38,430
p equals 1, p equals 2, p
equals 1, p equals 2.

165
00:08:38,430 --> 00:08:40,730
What's happening at
this point here?

166
00:08:40,730 --> 00:08:43,320
This point, we have three
phases in equilibrium.

167
00:08:43,320 --> 00:08:45,910
We have liquid, alpha,
and beta.

168
00:08:45,910 --> 00:08:47,510
And this is the special
point here.

169
00:08:47,510 --> 00:08:49,080
This is called the eutectic.

170
00:08:49,080 --> 00:08:54,080
This is the eutectic, which is
the temperature at which we

171
00:08:54,080 --> 00:08:57,480
get liquid, all liquid,
at the lowest value.

172
00:08:57,480 --> 00:09:00,570
So I'm going to call this here,
I'm going to call this

173
00:09:00,570 --> 00:09:04,020
point e, and e is
the eutectic.

174
00:09:09,380 --> 00:09:13,610
Lowest melting point
on the diagram.

175
00:09:13,610 --> 00:09:17,480
Comes from the Greek, meaning
easy melting.

176
00:09:17,480 --> 00:09:20,120
And at the eutectic, eutectic
is special.

177
00:09:20,120 --> 00:09:24,170
Here we have p equals 3.

178
00:09:24,170 --> 00:09:26,040
It's a triple point.

179
00:09:26,040 --> 00:09:28,290
The eutectic is a
triple point.

180
00:09:28,290 --> 00:09:29,740
OK.

181
00:09:29,740 --> 00:09:33,550
So now let's take a look
at some of the

182
00:09:33,550 --> 00:09:35,830
examples of such diagrams.

183
00:09:35,830 --> 00:09:37,320
All right?

184
00:09:37,320 --> 00:09:40,510
This is a good one now that
winter is upon us.

185
00:09:40,510 --> 00:09:43,640
This is the antifreeze
diagram.

186
00:09:43,640 --> 00:09:45,970
So on the left, I have pure
water, and on the right, I

187
00:09:45,970 --> 00:09:47,840
have pure ethylene glycol.

188
00:09:47,840 --> 00:09:50,550
And as you can see, if you add
glycol to water, you get

189
00:09:50,550 --> 00:09:52,010
freezing point depression.

190
00:09:52,010 --> 00:09:54,430
If you add water to glycol,
you get freezing point

191
00:09:54,430 --> 00:09:57,990
depression with a eutectic here
at roughly two-thirds.

192
00:09:57,990 --> 00:10:00,480
This is in volume percent,
because that's practical unit.

193
00:10:00,480 --> 00:10:03,300
When you mix glycol with water,
you do so by volume,

194
00:10:03,300 --> 00:10:06,830
not by mass, or certainly
not by moles.

195
00:10:06,830 --> 00:10:12,310
So if you mix two glycol with
one part water, you'll end up

196
00:10:12,310 --> 00:10:16,040
with a eutectic of minus 69
degrees C, or minus 92

197
00:10:16,040 --> 00:10:17,050
Fahrenheit.

198
00:10:17,050 --> 00:10:19,250
So that ought to take care
of your driving needs.

199
00:10:19,250 --> 00:10:20,260
All right?

200
00:10:20,260 --> 00:10:24,230
Now practically speaking, we
put an equal volume mix.

201
00:10:24,230 --> 00:10:27,110
So it's about a 50-50
glycol-water mix.

202
00:10:27,110 --> 00:10:31,420
And that gives you liquidus
depression down to about not

203
00:10:31,420 --> 00:10:32,370
quite minus 40.

204
00:10:32,370 --> 00:10:35,940
It's about minus 35 Fahrenheit,
which ought to

205
00:10:35,940 --> 00:10:37,630
take care of most peoples'
driving needs.

206
00:10:37,630 --> 00:10:41,340
Remember, what we're trying to
do is to prevent the liquid in

207
00:10:41,340 --> 00:10:43,280
the engine block
from freezing.

208
00:10:43,280 --> 00:10:47,860
because if it does freeze, you
know that ice has a larger

209
00:10:47,860 --> 00:10:51,950
volume than water, and that
energy is so great that you'll

210
00:10:51,950 --> 00:10:53,880
crack the engine block.

211
00:10:53,880 --> 00:10:56,100
So you have to prevent it from
freezing, the water from

212
00:10:56,100 --> 00:10:58,160
freezing, and so you
add the glycol.

213
00:10:58,160 --> 00:11:00,730
If, by chance, the temperature
dropped to minus 50, you'd

214
00:11:00,730 --> 00:11:02,550
still be OK, because you'd
be in the slush

215
00:11:02,550 --> 00:11:04,240
zone, two-phase regime.

216
00:11:04,240 --> 00:11:06,610
You'd have some water
ice forming, but

217
00:11:06,610 --> 00:11:08,010
you'd still have slush.

218
00:11:08,010 --> 00:11:10,370
And by the way, why does this
not look like this?

219
00:11:10,370 --> 00:11:16,450
It turns out that the amount of
solid solution behavior of

220
00:11:16,450 --> 00:11:19,020
a glycol in water is
vanishingly small.

221
00:11:19,020 --> 00:11:20,990
So this point is slammed
up over here.

222
00:11:20,990 --> 00:11:24,790
So that's why you don't see the
right side of the lens.

223
00:11:24,790 --> 00:11:27,950
And likewise, on the other
side, the amount of water

224
00:11:27,950 --> 00:11:30,870
that's soluble in glycol
is vanishingly small.

225
00:11:30,870 --> 00:11:35,350
So according to this scale, you
don't see the beta or the

226
00:11:35,350 --> 00:11:36,530
alpha phases here.

227
00:11:36,530 --> 00:11:40,100
It looks like it's pure, but
it can't be, because of the

228
00:11:40,100 --> 00:11:43,290
phase rule here.

229
00:11:43,290 --> 00:11:47,490
Now, you might say, well, why
don't we run pure glycol?

230
00:11:47,490 --> 00:11:49,700
Because somebody might say,
I'll just run pure glycol.

231
00:11:49,700 --> 00:11:52,020
Well, here's the problem with
running pure glycol.

232
00:11:52,020 --> 00:11:55,710
First of all, if you get beyond
two-thirds, the melting

233
00:11:55,710 --> 00:11:56,980
point rises.

234
00:11:56,980 --> 00:12:00,740
But then you could say, well,
but pure glycol, the solid

235
00:12:00,740 --> 00:12:04,220
glycol, has a smaller volume
than liquid glycol, so it

236
00:12:04,220 --> 00:12:06,730
wouldn't freeze and crack
the engine block.

237
00:12:06,730 --> 00:12:09,910
But there's another problem
here, and that is that the

238
00:12:09,910 --> 00:12:14,500
viscosity of water is 1 in these
units, centipoise, and

239
00:12:14,500 --> 00:12:15,950
glycol is 21.

240
00:12:15,950 --> 00:12:18,050
So you'd probably burn out your
water pump by running

241
00:12:18,050 --> 00:12:20,230
pure glycol, because it's so
viscous, the water pump is

242
00:12:20,230 --> 00:12:22,480
going to be fatigued
by running.

243
00:12:22,480 --> 00:12:23,530
And here's the point.

244
00:12:23,530 --> 00:12:31,330
This is the 50-50, minus
37 degrees Celsius.

245
00:12:31,330 --> 00:12:32,080
OK.

246
00:12:32,080 --> 00:12:35,940
And so what I've done, is I've
superimposed the solid-liquid

247
00:12:35,940 --> 00:12:37,870
diagrams with the liquid
vapor diagram.

248
00:12:37,870 --> 00:12:40,190
And this is one of the times
when nature is kind.

249
00:12:40,190 --> 00:12:43,220
So when you add glycol to water,
water is on the left

250
00:12:43,220 --> 00:12:46,590
here, as you add glycol to
water, you get freezing point

251
00:12:46,590 --> 00:12:50,010
depression, and you get boiling
point elevation.

252
00:12:50,010 --> 00:12:54,470
So adding glycol to water opens
up the liquid range.

253
00:12:54,470 --> 00:12:57,810
You want to stave off boiling,
because boiling will cause

254
00:12:57,810 --> 00:13:00,760
lousy cooling, and the engine
will overheat, and you want to

255
00:13:00,760 --> 00:13:03,730
stave off freezing, which will
cause the ice to form and

256
00:13:03,730 --> 00:13:05,720
crack the engine block,
and you get both.

257
00:13:05,720 --> 00:13:08,250
Then you put the pressure cap,
and then jump this up to about

258
00:13:08,250 --> 00:13:10,530
265 degrees Fahrenheit.

259
00:13:10,530 --> 00:13:13,370
So this is a very good example
of management of the

260
00:13:13,370 --> 00:13:17,040
properties of the coolant
through chemical change.

261
00:13:17,040 --> 00:13:19,810
And the binary phase diagram
eutectic type is a critical

262
00:13:19,810 --> 00:13:21,580
piece here.

263
00:13:21,580 --> 00:13:24,410
Again, apropos of the weather,
if you get ice on the

264
00:13:24,410 --> 00:13:27,210
sidewalks, if this rain freezes,
it's terrible here.

265
00:13:27,210 --> 00:13:30,110
Those of you who are in the
Northeast for the first time,

266
00:13:30,110 --> 00:13:30,930
this is bad.

267
00:13:30,930 --> 00:13:33,910
Not with what you see now, but
when this freezes, it's a

268
00:13:33,910 --> 00:13:35,580
skating rink, and you
can't see it.

269
00:13:35,580 --> 00:13:36,220
It's black ice.

270
00:13:36,220 --> 00:13:39,190
You're walking along, next
thing you're on your--

271
00:13:39,190 --> 00:13:41,960
you're in the horizontal
position, all right?

272
00:13:41,960 --> 00:13:46,250
So we can add sodium chloride
to water, and when we do, we

273
00:13:46,250 --> 00:13:49,580
cause this, a eutectic type
diagram, which can give you

274
00:13:49,580 --> 00:13:53,460
freezing point depression and
prevent ice formation, and if

275
00:13:53,460 --> 00:13:55,680
you get enough sodium chloride
in, you can get the

276
00:13:55,680 --> 00:14:00,290
temperature down to minus
21 degrees Celsius.

277
00:14:00,290 --> 00:14:01,650
And I've color coded
all of these.

278
00:14:01,650 --> 00:14:04,790
This is the liquidus, this is
the solidus, and then this

279
00:14:04,790 --> 00:14:08,570
line here, I can't remember if
we gave it a name last day,

280
00:14:08,570 --> 00:14:10,540
this is called solvus.

281
00:14:10,540 --> 00:14:11,630
This is the solvus.

282
00:14:11,630 --> 00:14:14,940
This is, we know, liquidus.

283
00:14:14,940 --> 00:14:20,530
This is liquidus, and this
one here is solidus.

284
00:14:20,530 --> 00:14:21,700
Yeah.

285
00:14:21,700 --> 00:14:22,420
OK.

286
00:14:22,420 --> 00:14:23,900
So this is all color coded.

287
00:14:23,900 --> 00:14:28,730
And notice that minus 21 Celsius
is not too different

288
00:14:28,730 --> 00:14:30,790
from 0 degrees Fahrenheit.

289
00:14:30,790 --> 00:14:33,410
Turns out, that's how the
Fahrenheit scale was born.

290
00:14:33,410 --> 00:14:36,620
Daniel Fahrenheit was a
glassblower in Leyden who also

291
00:14:36,620 --> 00:14:41,410
made exquisitely accurate
mercury thermometers.

292
00:14:41,410 --> 00:14:44,800
And he used ammonium chloride,
not sodium chloride.

293
00:14:44,800 --> 00:14:49,190
And the lowest temperature he
could get for all liquid with

294
00:14:49,190 --> 00:14:53,900
ammonium chloride, he pegged
as 0 on his scale.

295
00:14:53,900 --> 00:14:55,220
And it's roughly this.

296
00:14:55,220 --> 00:14:57,090
It's a little bit different,
but you can see the

297
00:14:57,090 --> 00:14:58,210
similarity.

298
00:14:58,210 --> 00:15:00,600
Now, you need two points
to define a scale.

299
00:15:00,600 --> 00:15:03,860
So he took this mercury in bulb
thermometer, put it in

300
00:15:03,860 --> 00:15:06,270
the eutectic mixture of ammonium
chloride and water,

301
00:15:06,270 --> 00:15:10,670
said, that's zero, calls in his
wife, tucks the mercury in

302
00:15:10,670 --> 00:15:15,290
bulb thermometer under her
armpit, and says, that's 96.

303
00:15:15,290 --> 00:15:17,130
And that's the birth of
the Fahrenheit scale.

304
00:15:17,130 --> 00:15:21,100
And that's why we have water
freezes at 32, and it boils at

305
00:15:21,100 --> 00:15:24,780
212, and all the
other nonsense.

306
00:15:24,780 --> 00:15:27,860
You know, it's 98.6, but here
it's a little bit colder.

307
00:15:27,860 --> 00:15:31,630
Now, why he chose 96 and 100
instead of 100 or something,

308
00:15:31,630 --> 00:15:33,060
you know, you could read
in the history.

309
00:15:33,060 --> 00:15:35,630
Maybe he wanted something
that was a power of two.

310
00:15:35,630 --> 00:15:38,520
I don't know what the reason for
it was, but that's why we

311
00:15:38,520 --> 00:15:40,540
have the Fahrenheit scale.

312
00:15:40,540 --> 00:15:41,270
OK.

313
00:15:41,270 --> 00:15:43,650
Now, maybe you're a little bit
hypertensive, so you don't

314
00:15:43,650 --> 00:15:46,190
want to throw sodium chloride
on your walk, so you can put

315
00:15:46,190 --> 00:15:47,180
potassium chloride.

316
00:15:47,180 --> 00:15:49,660
But you won't get much of a
freezing point depression, And

317
00:15:49,660 --> 00:15:52,110
point of fact, we usually salt
our roads with calcium

318
00:15:52,110 --> 00:15:54,930
chloride, which gives
you two advantages.

319
00:15:54,930 --> 00:15:57,380
Number one, very, very
low eutectic.

320
00:15:57,380 --> 00:16:00,480
Number two, it's a lot cheaper
than anything else.

321
00:16:00,480 --> 00:16:04,110
So it's the cheapest one to use,
and that's why we use it.

322
00:16:04,110 --> 00:16:07,120
Christmas is coming, and I told
you that phase diagrams

323
00:16:07,120 --> 00:16:07,970
would save the day.

324
00:16:07,970 --> 00:16:12,180
We saw that the cubic zirconia
was stable in pure zirconia

325
00:16:12,180 --> 00:16:15,710
only at temperatures above
2000 centigrade, which is

326
00:16:15,710 --> 00:16:20,240
useless for a ring, or other
such pieces of jewelry.

327
00:16:20,240 --> 00:16:25,270
But by the addition of calcium
oxide, we stabilize the cubic

328
00:16:25,270 --> 00:16:29,110
form of zirconia all the way
down to room temperature.

329
00:16:29,110 --> 00:16:32,130
And now we've got the high index
of refraction, clear,

330
00:16:32,130 --> 00:16:35,890
colorless gemstone that
passes for diamond.

331
00:16:35,890 --> 00:16:37,010
Poor man's diamond.

332
00:16:37,010 --> 00:16:38,430
Cubic zirconia.

333
00:16:38,430 --> 00:16:40,870
And you can see in
this regime here.

334
00:16:40,870 --> 00:16:43,220
And notice that cubic
zirconia--

335
00:16:43,220 --> 00:16:44,440
here's a eutectic.

336
00:16:44,440 --> 00:16:46,880
Why I'm showing you this is
that the zirconia- calcia

337
00:16:46,880 --> 00:16:49,230
system ultimately becomes
eutectic.

338
00:16:49,230 --> 00:16:53,390
And the eutectic is at about
2300 degrees C. But over here

339
00:16:53,390 --> 00:16:54,610
is the solid solution.

340
00:16:54,610 --> 00:16:57,510
Notice, if it's a solid
solution, that means

341
00:16:57,510 --> 00:16:58,800
it's p equals 1.

342
00:16:58,800 --> 00:16:59,890
Single phase.

343
00:16:59,890 --> 00:17:00,620
As it must be.

344
00:17:00,620 --> 00:17:03,580
If it were two phase,
the gemstone

345
00:17:03,580 --> 00:17:04,540
would be frosty, right?

346
00:17:04,540 --> 00:17:06,460
You'd have all those internal
surfaces, and they'd be

347
00:17:06,460 --> 00:17:07,700
reflecting.

348
00:17:07,700 --> 00:17:09,520
So this is clear
and colorless.

349
00:17:09,520 --> 00:17:11,960
And what's it bounded
by, this region?

350
00:17:11,960 --> 00:17:16,830
Cubic zirconia plus
calcium zirconate.

351
00:17:16,830 --> 00:17:20,890
So p equals 1, single-phase
field, p equals

352
00:17:20,890 --> 00:17:22,700
2, dual-phase field.

353
00:17:22,700 --> 00:17:24,170
And what's on the other side?

354
00:17:24,170 --> 00:17:28,410
Over here it's tetragonal solid
solution, single phase.

355
00:17:28,410 --> 00:17:31,270
Here's tetragonal solid
solution with cubic

356
00:17:31,270 --> 00:17:32,710
zirconia, two phase.

357
00:17:32,710 --> 00:17:34,960
Here's cubic zirconia,
one phase.

358
00:17:34,960 --> 00:17:37,440
Here's cubic zirconia with
calcium zirconate.

359
00:17:37,440 --> 00:17:38,180
Two phase.

360
00:17:38,180 --> 00:17:41,300
Same concept here. p equals
1, p equals 2. p

361
00:17:41,300 --> 00:17:43,140
equals 1, p equals 2.

362
00:17:43,140 --> 00:17:43,690
OK.

363
00:17:43,690 --> 00:17:44,290
So now you know.

364
00:17:44,290 --> 00:17:45,920
When you go in jewelry
store, ask the guy,

365
00:17:45,920 --> 00:17:47,310
is it single phase?

366
00:17:47,310 --> 00:17:48,660
He'll say, get out of here.

367
00:17:48,660 --> 00:17:50,110
Actually, you know
how they test?

368
00:17:50,110 --> 00:17:54,220
The index of refraction is
so high with zirconia.

369
00:17:54,220 --> 00:17:55,680
It's a little bit less
than diamond.

370
00:17:55,680 --> 00:17:57,260
Diamond's up around three.

371
00:17:57,260 --> 00:17:59,640
Cubic zirconia is over two.

372
00:17:59,640 --> 00:18:02,820
One of the ways they test is,
diamond has a very high band

373
00:18:02,820 --> 00:18:05,840
gap, about 5.5 electron volts.

374
00:18:05,840 --> 00:18:08,560
But it's got the remarkable
property, even though it's an

375
00:18:08,560 --> 00:18:14,000
electronic insulator, it's a
very good thermal conductor.

376
00:18:14,000 --> 00:18:17,970
Most materials that are poor
conductors of electricity are

377
00:18:17,970 --> 00:18:19,410
poor conductors of heat.

378
00:18:19,410 --> 00:18:22,270
But diamond, for reasons I can't
explain with just the

379
00:18:22,270 --> 00:18:26,810
utility of a 3091 education, has
a good phonon transmission

380
00:18:26,810 --> 00:18:27,750
properties.

381
00:18:27,750 --> 00:18:31,440
And the way they tell cubic
zirconia from diamond, is they

382
00:18:31,440 --> 00:18:35,000
actually put a couple of tips
on either side of the stone,

383
00:18:35,000 --> 00:18:40,040
and they heat one tip, and
measure the time lag for the

384
00:18:40,040 --> 00:18:42,510
thermal wave to get
to the other tip.

385
00:18:42,510 --> 00:18:45,290
And if it's cubic zirconia, it
takes a long time, because

386
00:18:45,290 --> 00:18:46,890
cubic zirconia is
an insulator.

387
00:18:46,890 --> 00:18:50,430
If it's diamond, it's almost
like metallic conduction.

388
00:18:50,430 --> 00:18:52,230
And that's how they
can tell a fake

389
00:18:52,230 --> 00:18:53,480
diamond from a real diamond.

390
00:18:56,190 --> 00:18:57,420
Here's, you know, I've
been drinking from

391
00:18:57,420 --> 00:18:59,230
these cans all semester.

392
00:18:59,230 --> 00:19:03,270
And this is the alloy system,
aluminum magnesium.

393
00:19:03,270 --> 00:19:06,430
So we put about 1% magnesium
into the aluminum.

394
00:19:06,430 --> 00:19:08,070
So here's pure aluminum
over here.

395
00:19:08,070 --> 00:19:10,170
It goes down to eutectic.

396
00:19:10,170 --> 00:19:11,410
This is pure magnesium
over here.

397
00:19:11,410 --> 00:19:13,530
They both melt at roughly
the same temperature.

398
00:19:13,530 --> 00:19:16,920
And by putting about 1%
magnesium in here, it changes

399
00:19:16,920 --> 00:19:18,980
the metallurgical properties
favorably.

400
00:19:18,980 --> 00:19:22,200
Notice we don't want to put 4%
or 5% magnesium in here.

401
00:19:22,200 --> 00:19:24,730
Otherwise, as we get down to
room temperature, we'll enter

402
00:19:24,730 --> 00:19:27,290
a two-phase regime,
and that means we

403
00:19:27,290 --> 00:19:28,320
won't be able to process.

404
00:19:28,320 --> 00:19:33,310
Because this can is made from
a single sheet of aluminum.

405
00:19:33,310 --> 00:19:34,370
The body of the can.

406
00:19:34,370 --> 00:19:36,140
There's two pieces, the
top and the body.

407
00:19:36,140 --> 00:19:39,510
There's no third bottom here.

408
00:19:39,510 --> 00:19:41,990
Start with a flat sheet of
aluminum and it's punched

409
00:19:41,990 --> 00:19:44,530
deep, drawn down, up,
down, and it gives

410
00:19:44,530 --> 00:19:45,950
you the whole shape.

411
00:19:45,950 --> 00:19:49,080
And you have to have, you
know, this is FCC.

412
00:19:49,080 --> 00:19:51,070
You have to have the glide.

413
00:19:51,070 --> 00:19:54,280
Dislocations are gliding, the
slip systems are operative,

414
00:19:54,280 --> 00:19:56,630
and the magnesium gives you just
a little bit of strength.

415
00:19:56,630 --> 00:20:00,190
But if you get into the
two-phase regime, the punch,

416
00:20:00,190 --> 00:20:03,540
instead of making deep
drawing metal, will

417
00:20:03,540 --> 00:20:05,360
end up punching holes.

418
00:20:05,360 --> 00:20:07,130
So what's the difference
between drawing

419
00:20:07,130 --> 00:20:08,060
and punching holes?

420
00:20:08,060 --> 00:20:10,100
It's all in the metallurgy.

421
00:20:10,100 --> 00:20:13,010
So you can see, this
is where we are.

422
00:20:13,010 --> 00:20:13,820
OK.

423
00:20:13,820 --> 00:20:14,790
Ah!

424
00:20:14,790 --> 00:20:16,040
Microelectronic devices.

425
00:20:16,040 --> 00:20:17,720
How do we hold all those
wires together?

426
00:20:17,720 --> 00:20:19,460
With solder.

427
00:20:19,460 --> 00:20:21,510
And this is the phase
diagram for solder.

428
00:20:21,510 --> 00:20:23,840
It's made of lead and tin.

429
00:20:23,840 --> 00:20:25,900
And we use eutectic.

430
00:20:25,900 --> 00:20:30,800
The eutectic here is about 62
weight percent tin at 183

431
00:20:30,800 --> 00:20:32,500
degrees Celsius.

432
00:20:32,500 --> 00:20:35,390
I took a class in high school
called Industrial Arts.

433
00:20:35,390 --> 00:20:36,930
It was shop.

434
00:20:36,930 --> 00:20:39,550
We had it drilled into us, the
eutectic point of soft solder

435
00:20:39,550 --> 00:20:42,580
is 374 degrees Fahrenheit.

436
00:20:42,580 --> 00:20:43,960
I will know that
on my deathbed.

437
00:20:43,960 --> 00:20:47,480
Plus the wavelength of copper
K-alpha radiation.

438
00:20:47,480 --> 00:20:50,112
1.5418 angstroms.

439
00:20:50,112 --> 00:20:51,380
Yeah.

440
00:20:51,380 --> 00:20:52,890
So what's the magic here?

441
00:20:52,890 --> 00:20:57,400
The magic here is, the solder
must be low-melting enough

442
00:20:57,400 --> 00:20:59,560
that when you're-- remember,
you've got your

443
00:20:59,560 --> 00:21:00,720
microelectronic device.

444
00:21:00,720 --> 00:21:03,090
You've already got your chip,
and you're putting wires.

445
00:21:03,090 --> 00:21:06,170
You want to put enough heat in
to solder the wires, but you

446
00:21:06,170 --> 00:21:08,790
don't want to have to raise the
temperature so much that

447
00:21:08,790 --> 00:21:11,020
you can damage the rest
of the device.

448
00:21:11,020 --> 00:21:12,280
So you say, well, why don't
you get something

449
00:21:12,280 --> 00:21:13,650
that's lower melting?

450
00:21:13,650 --> 00:21:16,390
Well, if it's lower melting,
you know from running your

451
00:21:16,390 --> 00:21:19,290
laptops and charging your cell
phones, they get warm.

452
00:21:19,290 --> 00:21:20,900
So it's a Goldilocks problem.

453
00:21:20,900 --> 00:21:23,620
If the melting point of the
solder is too low, you might

454
00:21:23,620 --> 00:21:25,910
encounter that temperature
in service, and

455
00:21:25,910 --> 00:21:27,460
pop all of the joints.

456
00:21:27,460 --> 00:21:30,040
If the melting point of the
solder is too high, then you

457
00:21:30,040 --> 00:21:33,730
have to use so much energy to
make the joints that you

458
00:21:33,730 --> 00:21:36,580
damage some of the
microelectronic componentry.

459
00:21:36,580 --> 00:21:40,190
So this has to be in the right
temperature range.

460
00:21:40,190 --> 00:21:42,930
The problem with this excellent,
excellent solder is

461
00:21:42,930 --> 00:21:44,660
that it contains lead.

462
00:21:44,660 --> 00:21:47,590
No one's going to get lead
poisoning from using a device.

463
00:21:47,590 --> 00:21:51,160
But the disposal of the device
ends up introducing the lead

464
00:21:51,160 --> 00:21:54,200
into the landfill, and then
if it soaks in an aqueous

465
00:21:54,200 --> 00:21:56,030
solution, you could get
leeching, et cetera.

466
00:21:56,030 --> 00:21:59,570
So there's a lot of research
right now on trying to find

467
00:21:59,570 --> 00:22:01,680
other solders that operate.

468
00:22:01,680 --> 00:22:04,600
And there are other solders,
but they're very expensive.

469
00:22:04,600 --> 00:22:07,260
So that, how do you find
something that's functional

470
00:22:07,260 --> 00:22:10,960
the way this is, nontoxic,
and cheap?

471
00:22:10,960 --> 00:22:13,440
They can give you any two of
those, but to get all three of

472
00:22:13,440 --> 00:22:15,030
them to line up?

473
00:22:15,030 --> 00:22:15,940
Requires research.

474
00:22:15,940 --> 00:22:18,535
You see the alpha phase, beta
phase, everything there.

475
00:22:18,535 --> 00:22:19,690
All right.

476
00:22:19,690 --> 00:22:22,795
And here's the lead
tin system.

477
00:22:22,795 --> 00:22:26,390
And let's just take this one
that happens to be 40%, and

478
00:22:26,390 --> 00:22:27,700
let's see what happens.

479
00:22:27,700 --> 00:22:28,710
We'll go through in time.

480
00:22:28,710 --> 00:22:31,120
So we start here, all
liquid regime.

481
00:22:31,120 --> 00:22:33,880
And so this bubble shows
what you might see on

482
00:22:33,880 --> 00:22:35,170
a microscope slide.

483
00:22:35,170 --> 00:22:37,910
So it's all white here, meaning
that it's homogeneous

484
00:22:37,910 --> 00:22:38,900
single phase.

485
00:22:38,900 --> 00:22:41,560
And then you drop into the
two-phase regime, just below

486
00:22:41,560 --> 00:22:44,150
the liquidus, and you start
seeing these blobs.

487
00:22:44,150 --> 00:22:47,030
Those little blobs are
the primary alpha.

488
00:22:47,030 --> 00:22:48,740
That's the solid solution,
right?

489
00:22:48,740 --> 00:22:50,320
Because we're in the two-phase
regime, so we've

490
00:22:50,320 --> 00:22:51,860
got a tie line here.

491
00:22:51,860 --> 00:22:54,920
We get down to a lower
temperature, there's more of

492
00:22:54,920 --> 00:22:55,510
this stuff.

493
00:22:55,510 --> 00:22:57,640
There's more of this stuff
forming , because

494
00:22:57,640 --> 00:22:59,140
it's forming in time.

495
00:22:59,140 --> 00:23:00,510
It takes you time to
traverse this.

496
00:23:00,510 --> 00:23:01,980
This isn't parking
and waiting.

497
00:23:01,980 --> 00:23:04,660
This is just cooling
something.

498
00:23:04,660 --> 00:23:07,540
Imagine you're soldering, so you
took the temperature up to

499
00:23:07,540 --> 00:23:10,810
here, now you're going
to let it cool.

500
00:23:10,810 --> 00:23:13,810
Once you cross the eutectic
temperature, now

501
00:23:13,810 --> 00:23:15,240
it's alpha plus beta.

502
00:23:15,240 --> 00:23:16,950
So now you get this lamellar
structure.

503
00:23:16,950 --> 00:23:20,360
Stripes of alpha,
stripes of beta.

504
00:23:20,360 --> 00:23:24,060
But the previous blobs that
formed the primary alpha, they

505
00:23:24,060 --> 00:23:25,190
don't disappear.

506
00:23:25,190 --> 00:23:26,530
The only way they
can disappear is

507
00:23:26,530 --> 00:23:27,860
by solid state diffusion.

508
00:23:27,860 --> 00:23:29,390
That's going to take
a long time.

509
00:23:29,390 --> 00:23:31,690
So I can look at the
microstructure

510
00:23:31,690 --> 00:23:33,560
here, and I can predict--

511
00:23:33,560 --> 00:23:34,140
not predict--

512
00:23:34,140 --> 00:23:36,930
I can go back and calculate
what the cooling

513
00:23:36,930 --> 00:23:38,270
rate must have been.

514
00:23:38,270 --> 00:23:42,090
If I cool very slowly,
I will have nearly

515
00:23:42,090 --> 00:23:44,240
the equilibrium structure.

516
00:23:44,240 --> 00:23:47,080
And so that's why, when I told
you about, say, analyzing the

517
00:23:47,080 --> 00:23:49,930
records from the World Trade
Center, I can look at the

518
00:23:49,930 --> 00:23:53,970
metal, and look at the phase
distribution, and tell you

519
00:23:53,970 --> 00:23:56,110
what the thermal history was.

520
00:23:56,110 --> 00:23:59,000
And so for example, there was
some cock-eyed theory saying

521
00:23:59,000 --> 00:24:01,890
that the steel was burning.

522
00:24:01,890 --> 00:24:05,380
Somebody said that the steel
melted, and so on.

523
00:24:05,380 --> 00:24:07,890
You can look and you say,
that did not happen.

524
00:24:07,890 --> 00:24:10,800
Temperatures went fairly high,
crossed into some different

525
00:24:10,800 --> 00:24:15,790
solid phases, went from BCC
to FCC and then back.

526
00:24:15,790 --> 00:24:16,540
But didn't melt.

527
00:24:16,540 --> 00:24:17,870
Because if it melted,
we would have seen

528
00:24:17,870 --> 00:24:19,690
this kind of structure.

529
00:24:19,690 --> 00:24:20,670
So this is--

530
00:24:20,670 --> 00:24:23,970
every time a plane crashes,
this is the metallurgical

531
00:24:23,970 --> 00:24:26,540
investigation that
is taking place.

532
00:24:26,540 --> 00:24:31,740
The history is written in
the microstructure.

533
00:24:31,740 --> 00:24:33,850
So this is a micrograph
that's actually

534
00:24:33,850 --> 00:24:35,780
taken from some solder.

535
00:24:35,780 --> 00:24:37,240
This is 50 weight percent.

536
00:24:37,240 --> 00:24:39,310
The slide was 40, but this
happened to be 50.

537
00:24:39,310 --> 00:24:40,850
It's the one I could
find easily.

538
00:24:40,850 --> 00:24:45,680
So 50 tin, 50 lead, and these
dark zones are the primary

539
00:24:45,680 --> 00:24:47,090
lead-rich alpha.

540
00:24:47,090 --> 00:24:48,380
And it's all metal.

541
00:24:48,380 --> 00:24:50,380
So how do I get the dark
and the light?

542
00:24:50,380 --> 00:24:52,820
First we polish, because it's
an optical microscope, which

543
00:24:52,820 --> 00:24:54,380
has a really crummy
depth of field.

544
00:24:54,380 --> 00:24:56,650
So you've got to make it flat,
and you polish it, and now

545
00:24:56,650 --> 00:24:57,940
you've got a mirror, and
you look, and all

546
00:24:57,940 --> 00:24:58,835
you see is your eyeball.

547
00:24:58,835 --> 00:25:01,950
So what you do then, is you
etch it with some acid.

548
00:25:01,950 --> 00:25:06,590
And the lead will etch at a
different rate from the tin.

549
00:25:06,590 --> 00:25:08,650
And the contrast, then,
is what you see here.

550
00:25:08,650 --> 00:25:10,810
So this is all the blobs
of primary alpha.

551
00:25:10,810 --> 00:25:13,550
Then you go below the eutectic,
and, you know, this

552
00:25:13,550 --> 00:25:15,790
cute little schematic
of stripes--

553
00:25:15,790 --> 00:25:18,320
this is the textbook version
of it, but this is the real

554
00:25:18,320 --> 00:25:18,720
version of it.

555
00:25:18,720 --> 00:25:21,760
And you see, it's a distorted
lamellar structure.

556
00:25:21,760 --> 00:25:22,920
Alternating stripes.

557
00:25:22,920 --> 00:25:26,240
Because you're trying to
make alpha and beta.

558
00:25:26,240 --> 00:25:28,190
And so you're making alpha and
beta, and the system's trying

559
00:25:28,190 --> 00:25:29,590
to make both of it.

560
00:25:29,590 --> 00:25:32,040
So it makes it in striped
form called lamellar

561
00:25:32,040 --> 00:25:33,470
microstructure.

562
00:25:33,470 --> 00:25:35,150
So I can look at that
and I can say, wow.

563
00:25:35,150 --> 00:25:38,440
That must have been cooled at
a fairly rapid rate, because

564
00:25:38,440 --> 00:25:40,890
you've got a large amounts
of primary alpha.

565
00:25:40,890 --> 00:25:43,230
If it were cooled at a very slow
rate, the thing should be

566
00:25:43,230 --> 00:25:45,110
all lamellar structure, right?

567
00:25:45,110 --> 00:25:47,200
If you're down here, there
should be no alpha.

568
00:25:47,200 --> 00:25:49,240
This is not the equilibrium
phase.

569
00:25:49,240 --> 00:25:51,110
So this alpha is
trapped there.

570
00:25:51,110 --> 00:25:52,360
It's a victim of its history.

571
00:25:55,490 --> 00:25:56,190
So there it is.

572
00:25:56,190 --> 00:25:56,900
That's cute.

573
00:25:56,900 --> 00:25:58,543
That's a nice, it's a
beautiful graphic.

574
00:25:58,543 --> 00:25:59,350
See?

575
00:25:59,350 --> 00:26:00,640
There it is.

576
00:26:00,640 --> 00:26:01,630
All right.

577
00:26:01,630 --> 00:26:04,170
So I'm going to show you some
phase diagrams from hell.

578
00:26:04,170 --> 00:26:06,230
This is, you're going
to be on airplanes.

579
00:26:06,230 --> 00:26:08,790
The airplane alloy is
aluminum copper.

580
00:26:08,790 --> 00:26:11,380
It's about 4% copper
and aluminum.

581
00:26:11,380 --> 00:26:14,090
Now remember, I just told you
about 1% magnesium and

582
00:26:14,090 --> 00:26:15,750
aluminum to give you
single phase.

583
00:26:15,750 --> 00:26:16,920
In the case of the airplane,
we want to

584
00:26:16,920 --> 00:26:18,800
make the wings strong.

585
00:26:18,800 --> 00:26:21,590
So what we do, is we come down
into here, which is a

586
00:26:21,590 --> 00:26:22,820
two-phase regime.

587
00:26:22,820 --> 00:26:26,240
And if we're clever about it,
we can control the particle

588
00:26:26,240 --> 00:26:29,080
size of that second phase.

589
00:26:29,080 --> 00:26:31,400
And by controlling the particle
size, we can cause

590
00:26:31,400 --> 00:26:33,880
grain boundaries, which can
arrest the dislocations and

591
00:26:33,880 --> 00:26:35,130
make sure the wings
don't fall off.

592
00:26:38,870 --> 00:26:40,160
This is aluminum manganese.

593
00:26:40,160 --> 00:26:42,620
This is the one that Danny
Schechtman worked with to get

594
00:26:42,620 --> 00:26:44,130
the quasicrystals.

595
00:26:44,130 --> 00:26:45,040
Look at all the phases.

596
00:26:45,040 --> 00:26:46,360
He's running out of Greek
letters by the time you get

597
00:26:46,360 --> 00:26:47,820
across this diagram.

598
00:26:47,820 --> 00:26:49,060
Look at it.

599
00:26:49,060 --> 00:26:50,470
But one thing holds.

600
00:26:50,470 --> 00:26:53,090
The two-phase regimes are
always bounded by

601
00:26:53,090 --> 00:26:54,030
single-phase regimes.

602
00:26:54,030 --> 00:26:54,160
Look.

603
00:26:54,160 --> 00:26:56,270
Here's liquid, here's a two
phases, there's a single

604
00:26:56,270 --> 00:26:57,910
phase, two phase, single
phase, two phase.

605
00:26:57,910 --> 00:26:58,880
Beautiful.

606
00:26:58,880 --> 00:27:00,130
All makes sense.

607
00:27:02,510 --> 00:27:05,140
Now, what happens if you try
to take a metal and mix it

608
00:27:05,140 --> 00:27:06,100
with a nonmetal?

609
00:27:06,100 --> 00:27:06,870
They don't want to mix.

610
00:27:06,870 --> 00:27:08,700
Look at the big miscibility
gap here.

611
00:27:08,700 --> 00:27:11,670
Molten iron doesn't want to
mix with molten sulfur.

612
00:27:11,670 --> 00:27:13,350
This is a liquid-liquid
miscibility gap.

613
00:27:13,350 --> 00:27:15,360
Over here, you can add some
sulfur to iron, you get a

614
00:27:15,360 --> 00:27:17,310
eutectic, get a line compound.

615
00:27:17,310 --> 00:27:19,260
And then over here, no dice.

616
00:27:19,260 --> 00:27:20,900
Does not want to mix.

617
00:27:20,900 --> 00:27:22,280
And look at all the
solid phases.

618
00:27:22,280 --> 00:27:24,030
Why do we have all these
solid phases?

619
00:27:24,030 --> 00:27:25,300
Different crystal structures.

620
00:27:28,180 --> 00:27:28,500
OK.

621
00:27:28,500 --> 00:27:30,890
So now what we're going to do,
is I'm going to talk about

622
00:27:30,890 --> 00:27:34,640
application of phase diagrams
to the making of champagne.

623
00:27:34,640 --> 00:27:38,400
Because champagne relies
on phase diagrams.

624
00:27:38,400 --> 00:27:40,540
And then I'm going to make
some general comments.

625
00:27:40,540 --> 00:27:42,760
But I'm going to actually
show you some champagne.

626
00:27:42,760 --> 00:27:46,340
So before I get into my
commentary, I'm going to get

627
00:27:46,340 --> 00:27:48,360
some champagne chilling.

628
00:27:48,360 --> 00:27:51,510
So first I have to show you
how to chill champagne.

629
00:27:51,510 --> 00:27:54,625
First I will show you how
not to chill champagne.

630
00:27:57,330 --> 00:27:59,000
This is how not to
chill champagne.

631
00:28:01,910 --> 00:28:04,070
And it's not because, OK,
we can put it in there.

632
00:28:04,070 --> 00:28:04,710
Why?

633
00:28:04,710 --> 00:28:09,200
Because, as I showed you last
day, with respect to the

634
00:28:09,200 --> 00:28:16,380
cooling of the engine coolant by
the radiator, if you have--

635
00:28:16,380 --> 00:28:21,512
if this a bottle here,
here's the contents,

636
00:28:21,512 --> 00:28:23,610
the precious contents.

637
00:28:23,610 --> 00:28:26,820
And I have this with
blocks of ice.

638
00:28:26,820 --> 00:28:32,680
The contact between the ice and
the bottle is sporadic,

639
00:28:32,680 --> 00:28:36,270
and I've got air in between, so
the quality of the cooling

640
00:28:36,270 --> 00:28:37,580
is very poor.

641
00:28:37,580 --> 00:28:40,876
So instead, what I do is I rely
on the phase diagram.

642
00:28:43,550 --> 00:28:45,970
So what do I do?

643
00:28:45,970 --> 00:28:47,580
What do I know about
the phase diagram?

644
00:28:47,580 --> 00:28:51,460
if I pour water in here, I will
thermostat the entire

645
00:28:51,460 --> 00:28:54,940
system, liquid plus solid,
at 0 degrees.

646
00:28:54,940 --> 00:28:56,350
Because the ice is probably,
I don't know,

647
00:28:56,350 --> 00:28:58,730
minus 3, minus 4 Celsius?

648
00:28:58,730 --> 00:29:01,420
But the air is 20, and
it gets in there, and

649
00:29:01,420 --> 00:29:02,970
it's very few atoms.

650
00:29:02,970 --> 00:29:04,060
It's crummy heat transfer.

651
00:29:04,060 --> 00:29:06,720
Instead, if I flood this with
water, the whole thing is

652
00:29:06,720 --> 00:29:08,890
thermostatted at 0 degrees C.

653
00:29:08,890 --> 00:29:11,050
So now I've got a good delta t,
because I started here at

654
00:29:11,050 --> 00:29:14,590
about 22 degrees C. I've
got a delta t, and it's

655
00:29:14,590 --> 00:29:15,730
a fixed law, right?

656
00:29:15,730 --> 00:29:17,140
It's going to be what?

657
00:29:17,140 --> 00:29:18,270
It's going to be the flux.

658
00:29:18,270 --> 00:29:20,840
The heat flux is going
to be minus thermal

659
00:29:20,840 --> 00:29:23,510
conductivity, dt by dx.

660
00:29:23,510 --> 00:29:27,470
It's Fickian type motion
of the thing.

661
00:29:27,470 --> 00:29:30,460
So let's do it.

662
00:29:30,460 --> 00:29:32,430
This is how you properly
chill--

663
00:29:32,430 --> 00:29:38,730
I'm told it also works for
sodas and fruit juices.

664
00:29:38,730 --> 00:29:41,240
This technique, I mean.

665
00:29:41,240 --> 00:29:44,290
But I do know that it works
with champagne.

666
00:29:44,290 --> 00:29:46,290
Now that's working
beautifully.

667
00:29:46,290 --> 00:29:49,130
I can just feel the heat
being extracted.

668
00:29:49,130 --> 00:29:49,410
OK.

669
00:29:49,410 --> 00:29:52,800
So now let's talk
about champagne.

670
00:29:52,800 --> 00:29:53,110
All right.

671
00:29:53,110 --> 00:29:55,320
So we're going to talk about
champagne and a great

672
00:29:55,320 --> 00:29:58,190
inventor, and the inventor
is the Widow Clicquot.

673
00:29:58,190 --> 00:30:00,250
This is the Veuve Clicquot
champagne.

674
00:30:00,250 --> 00:30:01,880
And veuve is the French
for widow.

675
00:30:01,880 --> 00:30:04,710
So Veuve Clicquot,
her real name was

676
00:30:04,710 --> 00:30:06,690
Nicole-Barbe Ponsardin.

677
00:30:06,690 --> 00:30:09,610
And in 1798, she married
Francois Clicquot.

678
00:30:09,610 --> 00:30:12,550
This is a big French
winemaking family.

679
00:30:12,550 --> 00:30:15,620
And he died and left her a
widow at the age of 27.

680
00:30:15,620 --> 00:30:19,470
She was very unusual for a
French woman in the 18th

681
00:30:19,470 --> 00:30:22,240
century, because they were
not involved in society.

682
00:30:22,240 --> 00:30:23,860
They were certainly not
involved in business.

683
00:30:23,860 --> 00:30:25,260
This woman was different.

684
00:30:25,260 --> 00:30:28,430
She decided to get under the
hood, and she took control of

685
00:30:28,430 --> 00:30:29,800
the winery.

686
00:30:29,800 --> 00:30:33,630
And I've written here, bold,
imaginative management.

687
00:30:33,630 --> 00:30:35,190
There's a fantastic
book about her.

688
00:30:35,190 --> 00:30:39,880
It's actually a very good book
portraying late 18th century,

689
00:30:39,880 --> 00:30:41,950
early 19th century France.

690
00:30:41,950 --> 00:30:43,530
And these are among her
accomplishments.

691
00:30:43,530 --> 00:30:46,150
Marketed champagne to all the
great courts of Europe.

692
00:30:46,150 --> 00:30:48,370
Champagne was a regional
beverage, drunk only in the

693
00:30:48,370 --> 00:30:49,770
Champagne region.

694
00:30:49,770 --> 00:30:52,500
And she created the myth,

695
00:30:52,500 --> 00:30:53,940
propagated the myth of champagne.

696
00:30:53,940 --> 00:30:56,970
You use it for festive
occasions, bought land in the

697
00:30:56,970 --> 00:30:59,010
best vineyards, quality
control.

698
00:30:59,010 --> 00:31:01,200
It's about the chemistry.

699
00:31:01,200 --> 00:31:02,870
Fought fiercely against
counterfeiting.

700
00:31:02,870 --> 00:31:05,570
As she started getting champagne
more recognition,

701
00:31:05,570 --> 00:31:07,980
people started making sparkling
wine and labeling it

702
00:31:07,980 --> 00:31:08,560
as champagne.

703
00:31:08,560 --> 00:31:11,500
She used the court system
to take them down.

704
00:31:11,500 --> 00:31:13,510
Established strict quality
control procedures.

705
00:31:13,510 --> 00:31:15,840
That's all about defending
the brand, and

706
00:31:15,840 --> 00:31:16,880
what's the quality control?

707
00:31:16,880 --> 00:31:19,460
It's the chemistry.

708
00:31:19,460 --> 00:31:22,010
Produced the first
rose champagne.

709
00:31:22,010 --> 00:31:24,400
The Pinot Noir grape
has a black skin.

710
00:31:24,400 --> 00:31:26,930
Depress, and then take the
juice, and away you go.

711
00:31:26,930 --> 00:31:30,340
What she did, is she let the
skin sit with the juice for

712
00:31:30,340 --> 00:31:33,980
long enough to give a
just a rose tinge.

713
00:31:33,980 --> 00:31:36,230
And then oversaw the invention
of new technology.

714
00:31:36,230 --> 00:31:37,180
Remouillage.

715
00:31:37,180 --> 00:31:40,100
And that's where the phase
diagrams come into play.

716
00:31:40,100 --> 00:31:43,920
Phase diagrams give us champagne
we enjoy today.

717
00:31:43,920 --> 00:31:44,970
So what's the problem?

718
00:31:44,970 --> 00:31:46,420
Champagne is cloudy.

719
00:31:46,420 --> 00:31:47,590
Why is it cloudy?

720
00:31:47,590 --> 00:31:48,580
Well, here's the chemistry.

721
00:31:48,580 --> 00:31:51,180
Here's how you make, this is
how you make all wine.

722
00:31:51,180 --> 00:31:52,640
It's one-stop shopping.

723
00:31:52,640 --> 00:31:53,440
You take the grape.

724
00:31:53,440 --> 00:31:56,200
The grape has sugar in
the grape juice.

725
00:31:56,200 --> 00:32:00,380
And yeast that attacks the
sugar is in the skin.

726
00:32:00,380 --> 00:32:03,830
So the yeast attacks the sugar
to make alcohol and CO2.

727
00:32:03,830 --> 00:32:08,500
So ethyl alcohol and CO2,
plus some insolubles.

728
00:32:08,500 --> 00:32:11,730
There are some insoluble
products of that reaction.

729
00:32:11,730 --> 00:32:13,340
And there's two types
of insolubles.

730
00:32:13,340 --> 00:32:15,700
Those that will settle, they're
called sedimentary,

731
00:32:15,700 --> 00:32:16,710
and those that won't settle.

732
00:32:16,710 --> 00:32:18,370
They're called suspended.

733
00:32:18,370 --> 00:32:21,450
And how do you get rid of
the sedimentary stuff?

734
00:32:21,450 --> 00:32:22,820
By mechanical separation.

735
00:32:22,820 --> 00:32:29,690
You let the juice sit, this
reaction is taking place, and

736
00:32:29,690 --> 00:32:32,580
the sedimentary stuff is turning
into gunk, and it sits

737
00:32:32,580 --> 00:32:33,930
at the bottom.

738
00:32:33,930 --> 00:32:35,880
And then periodically
you siphon.

739
00:32:35,880 --> 00:32:38,080
You siphon the juice off, and
you leave all the crud at the

740
00:32:38,080 --> 00:32:40,870
bottom of the barrel, and then
you go for a few more months,

741
00:32:40,870 --> 00:32:42,510
and then you siphon again.

742
00:32:42,510 --> 00:32:46,680
Well, that works for the
sedimentary stuff, but it

743
00:32:46,680 --> 00:32:48,890
won't work for champagne,
because as you're siphoning,

744
00:32:48,890 --> 00:32:50,530
you're letting out
all the gas.

745
00:32:50,530 --> 00:32:52,490
You see, you're trapping
this gas.

746
00:32:52,490 --> 00:32:55,500
The champagne has CO2 that's
naturally occurring.

747
00:32:55,500 --> 00:32:57,070
It's not carbonated.

748
00:32:57,070 --> 00:32:59,170
It's carbonated naturally.

749
00:32:59,170 --> 00:33:00,740
Not carbonated, man-made
carbonation.

750
00:33:00,740 --> 00:33:02,230
It's natural carbonation.

751
00:33:02,230 --> 00:33:05,160
So how do you separate the juice
from the crud without

752
00:33:05,160 --> 00:33:06,150
losing the gas?

753
00:33:06,150 --> 00:33:07,970
That's the problem.

754
00:33:07,970 --> 00:33:11,440
And by the way, the other stuff
that's suspended, they

755
00:33:11,440 --> 00:33:12,090
use tricks.

756
00:33:12,090 --> 00:33:13,570
You know, here's the
free body diagram.

757
00:33:13,570 --> 00:33:15,310
Remember, I showed you
this for milk.

758
00:33:15,310 --> 00:33:17,500
So what they do, is they add
things like eggshell, and the

759
00:33:17,500 --> 00:33:20,390
eggshell acts as a coagulant,
so the tiny particles that

760
00:33:20,390 --> 00:33:24,620
will float agglomerate to become
big enough that then

761
00:33:24,620 --> 00:33:25,530
they'll settle.

762
00:33:25,530 --> 00:33:28,670
Tiny particles of a given
density will float, large

763
00:33:28,670 --> 00:33:31,250
particles of the same
density will sink.

764
00:33:31,250 --> 00:33:33,700
So you need to coagulate,
and do that without

765
00:33:33,700 --> 00:33:34,880
spoiling the taste.

766
00:33:34,880 --> 00:33:36,390
Fantastic chemistry.

767
00:33:36,390 --> 00:33:38,270
So she comes along
with the answer.

768
00:33:38,270 --> 00:33:40,540
By the way, the early
champagne glasses

769
00:33:40,540 --> 00:33:41,820
were all cut crystal.

770
00:33:41,820 --> 00:33:43,080
Why were they cut crystal?

771
00:33:43,080 --> 00:33:45,470
Because the champagne
was cloudy.

772
00:33:45,470 --> 00:33:50,520
It tasted fantastic, but who
wanted-- it looked like swill!

773
00:33:50,520 --> 00:33:52,630
So how to make it clear?

774
00:33:52,630 --> 00:33:54,620
So what they did, is they made
champagne bottles with the

775
00:33:54,620 --> 00:33:57,090
deep ruts, and they still
do to this day.

776
00:33:57,090 --> 00:33:59,770
They have a deep rut here,
because the idea was, if you

777
00:33:59,770 --> 00:34:01,950
opened it carefully, you
wouldn't disturb

778
00:34:01,950 --> 00:34:03,030
so much of the crud.

779
00:34:03,030 --> 00:34:07,560
But it gets churned
up by the gas.

780
00:34:07,560 --> 00:34:11,060
So what she reasoned was, let's
turn him upside down,

781
00:34:11,060 --> 00:34:14,370
and let's have the crud settle
on the underside of the cork.

782
00:34:14,370 --> 00:34:16,980
And furthermore, 45 degrees
is the optimal angle.

783
00:34:16,980 --> 00:34:19,430
You know this from your
Newtonian mechanics.

784
00:34:19,430 --> 00:34:23,280
And then you turn them, so
you spiral the bottle.

785
00:34:23,280 --> 00:34:26,120
Turn them, and have all the crud
collect on the underside

786
00:34:26,120 --> 00:34:26,600
of the cork.

787
00:34:26,600 --> 00:34:27,630
I know what you're thinking.

788
00:34:27,630 --> 00:34:29,200
How are you going to
get the cork out?

789
00:34:29,200 --> 00:34:30,630
Now you take the cork out,
you're going to lose

790
00:34:30,630 --> 00:34:31,185
not just the gas.

791
00:34:31,185 --> 00:34:32,940
You're going to lose
the liquid, too.

792
00:34:32,940 --> 00:34:34,850
Ah, that's where the phase
diagrams come in.

793
00:34:34,850 --> 00:34:37,360
So here's a phase diagram
of ethanol water.

794
00:34:37,360 --> 00:34:38,610
And it's eutectic.

795
00:34:40,680 --> 00:34:41,990
Look at, way down here.

796
00:34:41,990 --> 00:34:44,930
In fact, ethanol makes a
really good antifreeze.

797
00:34:44,930 --> 00:34:45,260
Look!

798
00:34:45,260 --> 00:34:48,350
A little bit of-- go
way down here.

799
00:34:48,350 --> 00:34:51,980
Now, most wines are somewhere
between 10% and 15% alcohol,

800
00:34:51,980 --> 00:34:54,330
that gives you very modest
freezing point depression.

801
00:34:54,330 --> 00:34:56,360
Maybe about minus 5 Celsius.

802
00:34:56,360 --> 00:34:58,690
Which is why if you forget, you
put a wine bottle in the

803
00:34:58,690 --> 00:35:00,630
freezer and you forget about
it, and you've got your

804
00:35:00,630 --> 00:35:03,310
freezer really cranked to,
say, minus 5 Fahrenheit,

805
00:35:03,310 --> 00:35:07,110
you'll freeze the wine, and
it'll expand, because it's 90%

806
00:35:07,110 --> 00:35:10,980
water, and push the cork
out, make a mess.

807
00:35:10,980 --> 00:35:15,480
But remember, you only get
down to about minus 5.

808
00:35:15,480 --> 00:35:16,590
Remember, I showed
you this one?

809
00:35:16,590 --> 00:35:18,680
It gets down to minus 21.

810
00:35:18,680 --> 00:35:21,450
So what she reasoned was,
what if you took the

811
00:35:21,450 --> 00:35:24,400
bottle upside down?

812
00:35:24,400 --> 00:35:29,610
You've got all the crud on the
underside of the cork.

813
00:35:29,610 --> 00:35:33,090
What if you took the bottle and
put it into not water, but

814
00:35:33,090 --> 00:35:35,890
what if I put sodium
chloride in here?

815
00:35:35,890 --> 00:35:37,760
I still have my ice cubes,
only the temperature

816
00:35:37,760 --> 00:35:40,010
is now minus 21.

817
00:35:40,010 --> 00:35:43,440
And that's below the freezing
point of the alcohol, and now

818
00:35:43,440 --> 00:35:46,670
I've frozen an ice
plug in the neck.

819
00:35:46,670 --> 00:35:50,720
So now there's an ice plug
between the crud and the cork.

820
00:35:50,720 --> 00:35:54,590
So now I can turn the bottle
like this, just melt ever so

821
00:35:54,590 --> 00:35:57,570
slightly, and the pressure in
the bottle will blow the ice

822
00:35:57,570 --> 00:36:00,080
plug, take with it the crud out,
and then I quickly put

823
00:36:00,080 --> 00:36:01,590
the cork on top.

824
00:36:01,590 --> 00:36:05,576
And that's how every bottle
of champagne is made.

825
00:36:05,576 --> 00:36:08,530
And it all comes from these
phase diagrams.

826
00:36:08,530 --> 00:36:09,040
See?

827
00:36:09,040 --> 00:36:11,590
So you put it in brine.

828
00:36:11,590 --> 00:36:12,540
Minus 21.

829
00:36:12,540 --> 00:36:15,050
But this thing is
frozen already.

830
00:36:15,050 --> 00:36:16,640
That red is frozen.

831
00:36:16,640 --> 00:36:19,220
And now I've turned it right
side up, out it goes, takes

832
00:36:19,220 --> 00:36:21,070
the crud with it, put
the cork back on.

833
00:36:21,070 --> 00:36:22,640
So it's a combination
of this phase

834
00:36:22,640 --> 00:36:23,900
diagram, this phase diagram.

835
00:36:23,900 --> 00:36:28,410
Both eutectic phase diagrams
would give us clear champagne.

836
00:36:28,410 --> 00:36:31,450
Positively brilliant.

837
00:36:31,450 --> 00:36:32,780
So there it is.

838
00:36:32,780 --> 00:36:36,430
The invention and--

839
00:36:36,430 --> 00:36:38,050
oh, by the way.

840
00:36:38,050 --> 00:36:39,450
They call this--

841
00:36:39,450 --> 00:36:42,620
the English word remouillage
is riddling.

842
00:36:42,620 --> 00:36:45,100
So they have people that
actually go, and they, these

843
00:36:45,100 --> 00:36:49,550
wooden racks with the slots in
them at 45 degree angles, and

844
00:36:49,550 --> 00:36:52,620
all these bottles are pointed
downward, 45 degree angle.

845
00:36:52,620 --> 00:36:55,060
Guys come in every day, quarter
turn, quarter turn,

846
00:36:55,060 --> 00:36:55,830
quarter turn.

847
00:36:55,830 --> 00:36:57,370
French are very traditional.

848
00:36:57,370 --> 00:36:59,910
Few champagne wineries have
motorized, so they have this

849
00:36:59,910 --> 00:37:02,120
thing called giropalette.

850
00:37:02,120 --> 00:37:03,920
Gyrating pallet.

851
00:37:03,920 --> 00:37:07,720
The California champagne
wineries call it VLM.

852
00:37:07,720 --> 00:37:10,920
Very Large Machine.

853
00:37:10,920 --> 00:37:11,800
I kid you not.

854
00:37:11,800 --> 00:37:12,960
I didn't make that up.

855
00:37:12,960 --> 00:37:17,000
In California, the giropalette
is called VLM, which is Very

856
00:37:17,000 --> 00:37:18,530
Large Machine, dude.

857
00:37:18,530 --> 00:37:19,020
I guess.

858
00:37:19,020 --> 00:37:20,220
That's what they say.

859
00:37:20,220 --> 00:37:21,720
California.

860
00:37:21,720 --> 00:37:22,480
All right.

861
00:37:22,480 --> 00:37:27,390
So let's have a few words now
about the final exam.

862
00:37:27,390 --> 00:37:29,600
So you know, it's going
to be Tuesday, 9:00 to

863
00:37:29,600 --> 00:37:30,610
noon, Johnson Athletic.

864
00:37:30,610 --> 00:37:31,450
Three hours.

865
00:37:31,450 --> 00:37:33,750
You have three full hours, not
three times 50 minutes.

866
00:37:33,750 --> 00:37:35,710
Three full hours.

867
00:37:35,710 --> 00:37:37,350
But I'm not going to give you
three times the work.

868
00:37:37,350 --> 00:37:41,535
It's sort of a hybrid between
intensive coverage since T3,

869
00:37:41,535 --> 00:37:46,100
so sort of like a T4 and
a redemptory part.

870
00:37:46,100 --> 00:37:49,110
It'll go back, extensive
coverage of everything.

871
00:37:49,110 --> 00:37:50,340
One aid sheet.

872
00:37:50,340 --> 00:37:51,760
One aid sheet.

873
00:37:51,760 --> 00:37:52,940
I'm saying it three times.

874
00:37:52,940 --> 00:37:53,970
One aid sheet.

875
00:37:53,970 --> 00:37:56,030
Do not come in there with
a bunch of aid sheets.

876
00:37:56,030 --> 00:37:56,730
Well, I didn't know!

877
00:37:56,730 --> 00:37:57,660
I thought we could have--

878
00:37:57,660 --> 00:37:58,050
no!

879
00:37:58,050 --> 00:37:58,830
One aid sheet.

880
00:37:58,830 --> 00:38:00,350
That's all you need.

881
00:38:00,350 --> 00:38:01,690
And the TAs are smart.

882
00:38:01,690 --> 00:38:04,760
You know, every year somebody
tries to bring the origami and

883
00:38:04,760 --> 00:38:05,440
all that stuff.

884
00:38:05,440 --> 00:38:08,690
And they get caught, and
then-- you know.

885
00:38:08,690 --> 00:38:10,510
Bring your periodic table,
table of contents,

886
00:38:10,510 --> 00:38:11,340
calculator, a pen.

887
00:38:11,340 --> 00:38:12,920
No headphones, no audio.

888
00:38:12,920 --> 00:38:13,580
Please.

889
00:38:13,580 --> 00:38:16,170
Because people are writing,
they're trying to concentrate.

890
00:38:16,170 --> 00:38:18,430
I don't want to get into a
dispute over whether your

891
00:38:18,430 --> 00:38:20,240
music is too loud for
your neighbor.

892
00:38:20,240 --> 00:38:22,750
So let's just, out of
courtesy, no audio.

893
00:38:22,750 --> 00:38:24,900
You can go three hours
without your music.

894
00:38:24,900 --> 00:38:26,150
All right?

895
00:38:29,370 --> 00:38:31,730
What else.

896
00:38:31,730 --> 00:38:33,035
This is going to be comparable
difficulty

897
00:38:33,035 --> 00:38:34,710
to the monthly tests.

898
00:38:34,710 --> 00:38:36,250
Of course, read the
entire exam.

899
00:38:36,250 --> 00:38:37,890
You've got plenty of time.

900
00:38:37,890 --> 00:38:40,710
Most people are leaving
11:15, 11:30.

901
00:38:40,710 --> 00:38:43,330
It's not a race against
the clock.

902
00:38:43,330 --> 00:38:45,310
And make sure you show your
work, justify your

903
00:38:45,310 --> 00:38:48,300
conclusions, solve
algebraically.

904
00:38:48,300 --> 00:38:50,130
Stay confident.

905
00:38:50,130 --> 00:38:52,715
Do your own work, academic
honesty, all that applies.

906
00:38:55,490 --> 00:38:58,200
Now, your overall grade is
going to be based on many

907
00:38:58,200 --> 00:38:59,590
factors, including the trend.

908
00:38:59,590 --> 00:39:01,050
So we're going to look
at how you performed

909
00:39:01,050 --> 00:39:02,250
throughout the semester.

910
00:39:02,250 --> 00:39:04,820
You started off really strong,
and you crash and burn on the

911
00:39:04,820 --> 00:39:07,460
final, or you've done the math
and you say, I only need a 37

912
00:39:07,460 --> 00:39:10,280
on the final, and you go in
there, shooting for a 37, and

913
00:39:10,280 --> 00:39:15,460
you miss and you get a 35, and
your total average is 49.5?

914
00:39:15,460 --> 00:39:16,500
You go down.

915
00:39:16,500 --> 00:39:19,480
Because you've got a 49.5 and
you wrote a 35 on the final.

916
00:39:22,310 --> 00:39:23,710
I'm just telling you.

917
00:39:23,710 --> 00:39:26,410
Claim, you can have your
exam papers back.

918
00:39:26,410 --> 00:39:29,420
But don't come and see
us before Christmas.

919
00:39:29,420 --> 00:39:31,280
You can have them back
starting IAP.

920
00:39:31,280 --> 00:39:33,395
So starting January 4, you
can have your exams

921
00:39:33,395 --> 00:39:34,920
back, if you want them.

922
00:39:34,920 --> 00:39:36,770
And there's no time limit for
appeal, so you don't have to

923
00:39:36,770 --> 00:39:42,290
be bursting into your TA's
office on January 4 if you see

924
00:39:42,290 --> 00:39:43,620
that we've misgraded
something.

925
00:39:43,620 --> 00:39:45,670
You can come and see us.

926
00:39:45,670 --> 00:39:48,330
There will be some security
measures in place.

927
00:39:48,330 --> 00:39:51,830
It has not escaped my notice
that some people have

928
00:39:51,830 --> 00:39:55,120
attempted to erase answers that
were written in pencil,

929
00:39:55,120 --> 00:39:57,510
and then bring in this
newly brilliantly

930
00:39:57,510 --> 00:39:59,850
solved problem for regrading.

931
00:39:59,850 --> 00:40:03,620
And that's, of course,
qualifies as academic

932
00:40:03,620 --> 00:40:05,800
dishonesty, and I'll take you to
the committee on discipline

933
00:40:05,800 --> 00:40:06,410
if you try it.

934
00:40:06,410 --> 00:40:12,280
But just to inspire honesty
on a random basis, we'll

935
00:40:12,280 --> 00:40:14,270
photocopy about 5%
of the exams.

936
00:40:14,270 --> 00:40:16,810
So if you want to try this, the
question you've got to ask

937
00:40:16,810 --> 00:40:19,160
yourself is do you feel lucky?

938
00:40:21,990 --> 00:40:23,240
Do you?

939
00:40:25,170 --> 00:40:25,460
All right.

940
00:40:25,460 --> 00:40:27,360
So now it's time for some
personal observations.

941
00:40:27,360 --> 00:40:29,370
So I wrote them down.

942
00:40:29,370 --> 00:40:29,590
OK.

943
00:40:29,590 --> 00:40:32,550
So first thing is, you've
come a long way.

944
00:40:32,550 --> 00:40:33,620
Syllabus is full.

945
00:40:33,620 --> 00:40:36,520
You think about where we were
on day 1, you know, this is

946
00:40:36,520 --> 00:40:38,900
equations, stoichiometry,
all that baby stuff.

947
00:40:38,900 --> 00:40:41,120
And you know, look.

948
00:40:41,120 --> 00:40:43,330
So be proud of what
you've learned.

949
00:40:43,330 --> 00:40:44,260
Number two.

950
00:40:44,260 --> 00:40:47,030
I wish you much success
on the final.

951
00:40:47,030 --> 00:40:50,160
Remember, no grade that I assign
to you, or any of my

952
00:40:50,160 --> 00:40:54,440
colleagues assigns to you has
any relevance to your value as

953
00:40:54,440 --> 00:40:55,090
a human being.

954
00:40:55,090 --> 00:40:56,660
It's just a grade
in a subject.

955
00:40:56,660 --> 00:41:00,100
That's all it is.

956
00:41:00,100 --> 00:41:01,250
What's the worst thing
that can happen?

957
00:41:01,250 --> 00:41:04,210
Suppose you get all Fs, and
you're required to withdraw

958
00:41:04,210 --> 00:41:05,450
from the Institute.

959
00:41:05,450 --> 00:41:06,920
So what?

960
00:41:06,920 --> 00:41:08,380
So what?

961
00:41:08,380 --> 00:41:09,110
You know?

962
00:41:09,110 --> 00:41:10,500
You're all smart people.

963
00:41:10,500 --> 00:41:11,340
I know you're smart.

964
00:41:11,340 --> 00:41:13,020
I used to chair the Admissions
Committee.

965
00:41:13,020 --> 00:41:14,040
I know how smart you are.

966
00:41:14,040 --> 00:41:16,410
If you're getting all F's, this
is not the right place,

967
00:41:16,410 --> 00:41:18,220
it's not the right time
for you to be here.

968
00:41:18,220 --> 00:41:19,940
Look, I have no degrees
from this place.

969
00:41:19,940 --> 00:41:21,190
I feel great.

970
00:41:25,720 --> 00:41:31,330
I've been teaching here at MIT
for 32 years, and I've never

971
00:41:31,330 --> 00:41:33,450
enjoyed teaching as much as
I have this semester.

972
00:41:33,450 --> 00:41:36,520
This has been really a blast
to teach, really.

973
00:41:36,520 --> 00:41:40,240
I can't believe I said that
with a straight face.

974
00:41:40,240 --> 00:41:43,490
So of course it's not true.

975
00:41:43,490 --> 00:41:45,130
I want to think my staff.

976
00:41:45,130 --> 00:41:47,280
My TAs, sitting here.

977
00:41:47,280 --> 00:41:49,990
The tutors who helped out.

978
00:41:49,990 --> 00:41:52,480
Professor Demkowicz, who subbed
for me that time, when

979
00:41:52,480 --> 00:41:56,710
I had the visit of
President Obama.

980
00:41:56,710 --> 00:41:59,990
Administrators, the
audiovisual techs.

981
00:41:59,990 --> 00:42:03,720
Dave Broderick, who's done a
great job of making sure that

982
00:42:03,720 --> 00:42:05,350
we have sound and light.

983
00:42:05,350 --> 00:42:08,080
And the academic media
production services people,

984
00:42:08,080 --> 00:42:12,030
who have recorded the lectures
so that on the rare occasion

985
00:42:12,030 --> 00:42:14,990
that you didn't make it
the class, you're

986
00:42:14,990 --> 00:42:18,050
able to catch up.

987
00:42:18,050 --> 00:42:21,720
And the last thing is that,
I've got here, there's one

988
00:42:21,720 --> 00:42:22,740
more chemistry lesson.

989
00:42:22,740 --> 00:42:25,430
You know, we've learned about
the four different types of

990
00:42:25,430 --> 00:42:26,890
primary bonding.

991
00:42:26,890 --> 00:42:29,520
Covalent, ionic, metallic,
and in some

992
00:42:29,520 --> 00:42:30,570
instances, van der Waals.

993
00:42:30,570 --> 00:42:32,310
But there's a fifth
type of bond.

994
00:42:32,310 --> 00:42:34,660
The fifth type of bond that I
haven't talked about yet.

995
00:42:34,660 --> 00:42:36,970
And it's the type of bond that's
been forming in this

996
00:42:36,970 --> 00:42:40,390
room over the last 14 weeks.

997
00:42:40,390 --> 00:42:40,840
Yeah, I know.

998
00:42:40,840 --> 00:42:41,600
It's kind of sappy.

999
00:42:41,600 --> 00:42:43,950
I didn't come up with this.

1000
00:42:43,950 --> 00:42:46,690
It came from a student.

1001
00:42:46,690 --> 00:42:49,760
So the fifth type of bond is--

1002
00:42:49,760 --> 00:42:50,837
it's not this one.

1003
00:42:50,837 --> 00:42:53,460
[MUSIC PLAYBACK]

1004
00:42:53,460 --> 00:42:55,640
No, it's not this one.

1005
00:42:55,640 --> 00:42:58,300
It's a bond that's formed
between people, and this bond

1006
00:42:58,300 --> 00:43:00,500
has a very special property.

1007
00:43:00,500 --> 00:43:03,820
It can never be broken.

1008
00:43:03,820 --> 00:43:04,330
I know!

1009
00:43:04,330 --> 00:43:05,270
It came from a student.

1010
00:43:05,270 --> 00:43:06,170
It's very sappy.

1011
00:43:06,170 --> 00:43:07,190
I'll tell you the story.

1012
00:43:07,190 --> 00:43:08,530
I'll tell you the story
how it happened.

1013
00:43:08,530 --> 00:43:10,610
I used to teach 321,
which is a core

1014
00:43:10,610 --> 00:43:12,570
graduate class in kinetics.

1015
00:43:12,570 --> 00:43:13,870
And I'd been teaching
it for, I don't

1016
00:43:13,870 --> 00:43:14,900
know, five, seven years.

1017
00:43:14,900 --> 00:43:16,710
And I was at a conference, and
there's these two people

1018
00:43:16,710 --> 00:43:17,540
standing there talking.

1019
00:43:17,540 --> 00:43:18,640
And I know both them.

1020
00:43:18,640 --> 00:43:21,750
One was from industry, and
one of them was an alum.

1021
00:43:21,750 --> 00:43:24,420
So I go up, and the fellow in
industry, says, hi, how are

1022
00:43:24,420 --> 00:43:25,590
you doing, do you
know so and so?

1023
00:43:25,590 --> 00:43:26,400
And I said, yeah.

1024
00:43:26,400 --> 00:43:28,010
He was at MIT.

1025
00:43:28,010 --> 00:43:29,910
I was his kinetics professor

1026
00:43:29,910 --> 00:43:33,010
And the student, the alum,
he says, excuse

1027
00:43:33,010 --> 00:43:34,240
me, Professor Sadoway.

1028
00:43:34,240 --> 00:43:39,650
It's true that I was at MIT, but
please do not say that you

1029
00:43:39,650 --> 00:43:41,280
were my kinetics professor.

1030
00:43:41,280 --> 00:43:44,070
You will always be my
kinetics professor.

1031
00:43:44,070 --> 00:43:46,630
I went, oh, man.

1032
00:43:46,630 --> 00:43:47,690
This is really something.

1033
00:43:47,690 --> 00:43:49,500
So now the tables are turned.

1034
00:43:49,500 --> 00:43:52,600
And, and, you know, I know
you're going to go go on and

1035
00:43:52,600 --> 00:43:55,470
do something remarkable in your
life, and I hope it's

1036
00:43:55,470 --> 00:43:57,740
remarkably wonderful and
not remarkably stupid.

1037
00:43:57,740 --> 00:44:02,590
But you know, at some point,
somebody may say to you, where

1038
00:44:02,590 --> 00:44:03,595
did you learn your chemistry?

1039
00:44:03,595 --> 00:44:05,810
And you'll have to say,
Sadoway at MIT.

1040
00:44:05,810 --> 00:44:09,810
So whether you like it or not,
I will always be your

1041
00:44:09,810 --> 00:44:11,550
chemistry professor.

1042
00:44:11,550 --> 00:44:13,560
So now, let's see.

1043
00:44:13,560 --> 00:44:17,520
I think it's time to open
up the champagne.

1044
00:44:17,520 --> 00:44:18,850
So first thing, we
have to teach

1045
00:44:18,850 --> 00:44:19,900
you how to open champagne.

1046
00:44:19,900 --> 00:44:22,840
So there's the foil here.

1047
00:44:22,840 --> 00:44:24,090
So we'll take the foil off.

1048
00:44:27,880 --> 00:44:31,320
Take the foil off,
very carefully.

1049
00:44:31,320 --> 00:44:35,220
And then there's the wire basket
that keeps the cork on.

1050
00:44:35,220 --> 00:44:37,880
How many turns on
the wire basket?

1051
00:44:37,880 --> 00:44:39,830
Everyone in 3091 knows.

1052
00:44:39,830 --> 00:44:42,150
Six turns.

1053
00:44:42,150 --> 00:44:47,560
One, two, three, four,
five, six.

1054
00:44:47,560 --> 00:44:50,570
Six turns.

1055
00:44:50,570 --> 00:44:52,680
And so now, I don't want to
point that at anybody, because

1056
00:44:52,680 --> 00:44:55,710
the only thing between me
and six atmospheres of

1057
00:44:55,710 --> 00:44:58,170
pressure is that cork.

1058
00:44:58,170 --> 00:45:02,230
And Dave, if we can cut to
the document camera.

1059
00:45:02,230 --> 00:45:07,220
The cover, the metal cover on
this, has the image of the

1060
00:45:07,220 --> 00:45:07,920
Widow Clicquot.

1061
00:45:07,920 --> 00:45:11,360
This is Veuve Clicquot, and
this is the image of the

1062
00:45:11,360 --> 00:45:13,560
Veuve, and she's on
every bottle.

1063
00:45:13,560 --> 00:45:16,630
She was the one that gave us
clarified champagne, so you

1064
00:45:16,630 --> 00:45:17,750
thank her very much.

1065
00:45:17,750 --> 00:45:19,590
All right.

1066
00:45:19,590 --> 00:45:20,635
So now what we're going
to do, is we're going

1067
00:45:20,635 --> 00:45:21,495
to open this thing.

1068
00:45:21,495 --> 00:45:23,990
To open it, we point
it 45 degrees and

1069
00:45:23,990 --> 00:45:25,600
turn it ever so slightly.

1070
00:45:25,600 --> 00:45:27,430
Never point it at people.

1071
00:45:27,430 --> 00:45:28,960
No, really, point it away.

1072
00:45:28,960 --> 00:45:31,480
You'll put an eye out
with this thing.

1073
00:45:31,480 --> 00:45:33,610
You turn it very slightly.

1074
00:45:33,610 --> 00:45:36,840
Actually, my hands are wet now,
so I'm going to use a

1075
00:45:36,840 --> 00:45:38,090
towel here.

1076
00:45:48,400 --> 00:45:49,626
Oh yeah.

1077
00:45:49,626 --> 00:45:51,040
Go like this.

1078
00:45:51,040 --> 00:45:52,300
You like the suspense, huh?

1079
00:46:01,880 --> 00:46:03,610
See that?

1080
00:46:03,610 --> 00:46:05,450
No pfff!

1081
00:46:05,450 --> 00:46:07,010
That's for football
locker rooms.

1082
00:46:07,010 --> 00:46:09,010
It's very declasse.

1083
00:46:09,010 --> 00:46:09,930
OK.

1084
00:46:09,930 --> 00:46:12,090
Now we have to have a glass.

1085
00:46:12,090 --> 00:46:14,690
So since we have clarified
champagne, we're not going to

1086
00:46:14,690 --> 00:46:15,490
use cut crystal.

1087
00:46:15,490 --> 00:46:20,130
We're going to use Baccarat,
French crystal that's not cut.

1088
00:46:20,130 --> 00:46:23,650
Because we've got nothing
to hide, right?

1089
00:46:23,650 --> 00:46:24,710
So now we're going
to pour this.

1090
00:46:24,710 --> 00:46:27,350
And the rut now has
some value.

1091
00:46:27,350 --> 00:46:31,310
The rut has value, because
now what you can do is to

1092
00:46:31,310 --> 00:46:32,770
pour it like so.

1093
00:46:38,670 --> 00:46:42,752
I've been waiting fourteen
weeks for this.

1094
00:46:42,752 --> 00:46:43,280
All right.

1095
00:46:43,280 --> 00:46:45,240
So the surface tension, you
see the carbon dioxide

1096
00:46:45,240 --> 00:46:46,970
outgassing, because it's
supersaturated.

1097
00:46:46,970 --> 00:46:50,500
Six atmospheres, not
one atmosphere.

1098
00:46:50,500 --> 00:46:55,560
The bubbles are nucleating on
the defects in the glass.

1099
00:46:55,560 --> 00:46:57,296
It's all about chemistry.

1100
00:46:57,296 --> 00:46:58,546
So there we go.

1101
00:47:01,120 --> 00:47:01,400
OK.

1102
00:47:01,400 --> 00:47:06,480
So I'm going to propose a toast
to the class, to the

1103
00:47:06,480 --> 00:47:11,820
3091 class of Fall 2009, to wish
you much success in your

1104
00:47:11,820 --> 00:47:15,230
academic pursues, and
much happiness in

1105
00:47:15,230 --> 00:47:16,990
your personal lives.

1106
00:47:16,990 --> 00:47:22,470
And with that, I'm
going to find out

1107
00:47:22,470 --> 00:47:23,720
what's going on inside.

1108
00:47:26,700 --> 00:47:27,690
Look at those bubbles!

1109
00:47:27,690 --> 00:47:32,240
You know, the legend is, the
blind monk, Dom Perignon, when

1110
00:47:32,240 --> 00:47:34,870
he first drank champagne, said,
I feel as though I'm

1111
00:47:34,870 --> 00:47:36,120
drinking stars.

1112
00:47:39,890 --> 00:47:41,820
He's right.

1113
00:47:41,820 --> 00:47:42,540
Drinking stars.

1114
00:47:42,540 --> 00:47:42,810
OK.

1115
00:47:42,810 --> 00:47:44,460
This is to you.