1
00:00:01,440 --> 00:00:04,880
The alchemists were a mysterious
group of medieval scientists

2
00:00:04,880 --> 00:00:09,120
who believed their knowledge of
chemistry gave them magical powers.

3
00:00:09,120 --> 00:00:13,640
They could summon fire,
produce mystical potions.

4
00:00:13,640 --> 00:00:18,000
They even tried to turn
metals into gold.

5
00:00:19,280 --> 00:00:24,000
Their magnificent feats enthralled
kings and commoners alike.

6
00:00:24,000 --> 00:00:26,760
But they never revealed
their secrets.

7
00:00:26,760 --> 00:00:28,880
By pushing the frontiers of science,

8
00:00:28,880 --> 00:00:31,720
modern chemists can perform
equally impressive feats,

9
00:00:31,720 --> 00:00:33,920
and we're happy to tell you
everything.

10
00:00:55,240 --> 00:00:57,520
APPLAUSE

11
00:01:05,320 --> 00:01:08,440
Chemistry gives us an understanding
of the world

12
00:01:08,440 --> 00:01:11,120
that the other sciences just don't.

13
00:01:11,120 --> 00:01:14,760
It's all about how one
substance interacts with another

14
00:01:14,760 --> 00:01:17,400
to give us something new.

15
00:01:17,400 --> 00:01:22,240
Thank you. Take this Christmas
tree here, for instance.

16
00:01:22,240 --> 00:01:28,520
A nice, solid structure, but watch
what happens when I do this.

17
00:01:30,160 --> 00:01:31,600
Whoa!

18
00:01:35,800 --> 00:01:37,400
APPLAUSE

19
00:01:44,000 --> 00:01:48,240
Well, we certainly
saw that a change took place there.

20
00:01:48,240 --> 00:01:52,240
That was a flash of light,
I felt a blast of heat,

21
00:01:52,240 --> 00:01:55,760
heard a whoosh of sound
and then nothing was left at all.

22
00:01:55,760 --> 00:01:58,320
Trying to understand what happens

23
00:01:58,320 --> 00:02:02,280
when one thing changes into another
is chemistry.

24
00:02:02,280 --> 00:02:06,040
My name is Dr Peter Wothers,
and I am a chemist.

25
00:02:06,040 --> 00:02:07,360
APPLAUSE

26
00:02:10,600 --> 00:02:13,960
Now, the ancient Greeks thought that
everything around them

27
00:02:13,960 --> 00:02:16,520
was made up of just four elements.

28
00:02:16,520 --> 00:02:19,680
Air, water, earth and fire.

29
00:02:19,680 --> 00:02:21,240
We see these here.

30
00:02:21,240 --> 00:02:24,440
In the next three lectures,
we're going to look at what air,

31
00:02:24,440 --> 00:02:27,480
water and earth
are really made up of.

32
00:02:27,480 --> 00:02:32,560
But don't worry,
there will be plenty of fire
in all of the lectures.

33
00:02:32,560 --> 00:02:35,560
But this brings me
to one important point.

34
00:02:35,560 --> 00:02:38,840
Please do not try
these experiments at home.

35
00:02:38,840 --> 00:02:41,880
By understanding the elements
around us,

36
00:02:41,880 --> 00:02:44,720
the modern building blocks
of science,

37
00:02:44,720 --> 00:02:47,480
we need to look at the world
in a different way,

38
00:02:47,480 --> 00:02:50,960
we need to see these elements
through the eyes of a chemist.

39
00:02:50,960 --> 00:02:52,480
By understanding these elements,

40
00:02:52,480 --> 00:02:56,720
we can make better materials
and better medicines for our future.

41
00:02:56,720 --> 00:03:00,480
We're going to start this
first lecture looking at the air.

42
00:03:00,480 --> 00:03:03,640
Now, of course, this is something
that we rarely think about,

43
00:03:03,640 --> 00:03:05,880
but without it, we'd all be dead.

44
00:03:05,880 --> 00:03:08,720
But just to show you that
it really is here around us

45
00:03:08,720 --> 00:03:11,440
pushing down on this,
I've got a demonstration,

46
00:03:11,440 --> 00:03:14,160
but I'd like a
volunteer from the audience, please.

47
00:03:14,160 --> 00:03:16,560
Right on the corner there,
at the back, yes,

48
00:03:16,560 --> 00:03:19,280
would you like to come down
to the front, please?

49
00:03:21,720 --> 00:03:24,760
OK. Now. What's your name, please?
Xavier. Xavier. OK.

50
00:03:24,760 --> 00:03:27,200
Right. So, see this here?
This is just a normal oil drum.

51
00:03:27,200 --> 00:03:30,440
It seems to be
covered in a bit of rubbish.

52
00:03:30,440 --> 00:03:33,680
Hold this, give it a good whack.

53
00:03:33,680 --> 00:03:35,880
Go on, bit harder than that. OK.

54
00:03:35,880 --> 00:03:39,160
It really is quite solid, isn't
it? On the top as well, maybe. OK.

55
00:03:39,160 --> 00:03:41,600
Yeah. Do you think
it's pretty solid? Yeah.

56
00:03:41,600 --> 00:03:45,880
Now, watch what happens when we take
the air out of this drum.

57
00:03:45,880 --> 00:03:49,120
At the moment, there is of course
a scope open at the top here,

58
00:03:49,120 --> 00:03:52,560
there's air inside, air outside, but
we're going to put this pump on here

59
00:03:52,560 --> 00:03:57,080
so we're now removing
the air from this drum.

60
00:03:57,080 --> 00:04:01,760
OK. And... That's good. I think you
should just step back. That's it.

61
00:04:01,760 --> 00:04:05,240
You stand over there.
I'll stand over here.

62
00:04:05,240 --> 00:04:09,840
OK, so we're removing the air
from the inside of this drum.

63
00:04:09,840 --> 00:04:12,200
To start off with,
the air molecules were pushing

64
00:04:12,200 --> 00:04:17,360
against the drum, but they're also
pushing from the outside as well.

65
00:04:17,360 --> 00:04:20,800
So what do you think will happen
if we remove the air from inside?

66
00:04:20,800 --> 00:04:23,280
Any ideas? It will shrink.
It will shrink?

67
00:04:23,280 --> 00:04:26,680
So do you think it will gradually
shrink up and get smaller?

68
00:04:26,680 --> 00:04:29,080
Yeah? Well, that's a good idea.
That's what we think.

69
00:04:29,080 --> 00:04:31,760
It doesn't seem to be doing
very much at the moment, does it?

70
00:04:31,760 --> 00:04:33,560
So, not a lot.

71
00:04:33,560 --> 00:04:36,960
Well, supposedly,
these little air molecules

72
00:04:36,960 --> 00:04:41,120
are all pushing down on this can
here. We're taking...

73
00:04:41,120 --> 00:04:42,120
BANG!

74
00:04:42,120 --> 00:04:44,160
GASPING

75
00:04:52,960 --> 00:04:58,480
Come and have a look. You feel that.
It is very solid, isn't it?

76
00:04:58,480 --> 00:05:00,840
Yeah. That was just the air.

77
00:05:00,840 --> 00:05:04,080
So we do forget about it,
but it really is pushing down on us.

78
00:05:04,080 --> 00:05:05,600
It's quite a strong force.

79
00:05:05,600 --> 00:05:09,560
It's like there's two full-grown men
standing on your shoulders.

80
00:05:09,560 --> 00:05:12,400
We don't notice it because we're
used to it, we've adapted to it.

81
00:05:12,400 --> 00:05:15,240
Thank you very much. Give him
a round of applause. Thank you.

82
00:05:15,240 --> 00:05:16,880
APPLAUSE

83
00:05:22,560 --> 00:05:26,200
But what about our tree?
What happened to the tree?

84
00:05:26,200 --> 00:05:29,440
Well, what would the ancient Greeks
have thought if they had seen that?

85
00:05:29,440 --> 00:05:33,080
What would they have made
of this strange substance?

86
00:05:33,080 --> 00:05:36,160
Well, this, actually,
the Greeks never saw.

87
00:05:36,160 --> 00:05:38,120
This is a substance
called guncotton.

88
00:05:38,120 --> 00:05:41,240
It was only discovered
around 200 years ago.

89
00:05:41,240 --> 00:05:42,680
It's quite remarkable.

90
00:05:42,680 --> 00:05:47,720
The Greeks would've said that this
is changing into fire and air.

91
00:05:47,720 --> 00:05:51,800
Maybe they would've said
this is made of fire and air.

92
00:05:51,800 --> 00:05:54,840
Or maybe they would've
just said it's magic.

93
00:05:54,840 --> 00:05:57,320
Either way, they would be wrong.

94
00:05:57,320 --> 00:06:00,680
We now know that the air
is much more complicated.

95
00:06:00,680 --> 00:06:03,800
It's a mixture
of different components.

96
00:06:03,800 --> 00:06:08,440
To show exactly what the air is made
up of, again I need a volunteer.

97
00:06:08,440 --> 00:06:10,520
There's a hand very quickly.
I saw your hand.

98
00:06:10,520 --> 00:06:12,840
Would you like to come down,
please? Thank you.

99
00:06:12,840 --> 00:06:14,760
Can we have a round of applause,
please?

100
00:06:16,680 --> 00:06:20,480
OK, your hand shot up very quickly
there. What's your name? Nadia.

101
00:06:20,480 --> 00:06:24,120
Nadia. OK, excellent.
Now, have you made air before?

102
00:06:24,120 --> 00:06:26,160
Oh, having to think about that one.

103
00:06:26,160 --> 00:06:29,920
Have you made air before,
mixed it up? No. Exactly.

104
00:06:29,920 --> 00:06:32,560
Of course, the alchemist would never
have done this, either.

105
00:06:32,560 --> 00:06:35,640
They didn't know what was in the
air. Do you know what's in the air?

106
00:06:35,640 --> 00:06:39,560
No. No. No? Oh, come on, have a
guess. Do you know any of the gases?

107
00:06:39,560 --> 00:06:42,800
Oxygen. Very good, you see, oxygen.
Do you know any other ones?

108
00:06:42,800 --> 00:06:45,240
Carbon dioxide.
Carbon dioxide, exactly.

109
00:06:45,240 --> 00:06:47,880
So we're going to see how many
of the different gases are in air.

110
00:06:47,880 --> 00:06:49,480
Would you like to come over here?

111
00:06:49,480 --> 00:06:51,520
So these are some gas cylinders,

112
00:06:51,520 --> 00:06:53,960
and we've got the
different proportions of the air

113
00:06:53,960 --> 00:06:56,640
you're going to add to this
cylinder of water here.

114
00:06:56,640 --> 00:06:59,040
OK. Now, the first one
is the most common gas.

115
00:06:59,040 --> 00:07:01,920
It's not oxygen, and it's not carbon
dioxide. Does anybody else know?

116
00:07:01,920 --> 00:07:04,520
Do you want to shout it out?
Nitrogen.

117
00:07:04,520 --> 00:07:07,320
Nitrogen. Yes, exactly.
So the most common gas is nitrogen,

118
00:07:07,320 --> 00:07:08,760
and this is what we have here,

119
00:07:08,760 --> 00:07:11,440
so I'd like you to turn the tap
for me, please. This tap here.

120
00:07:11,440 --> 00:07:14,040
This is going to let
some nitrogen in.

121
00:07:14,040 --> 00:07:17,960
Now, we're aiming to get to
this mark here.

122
00:07:17,960 --> 00:07:23,440
This is 78%. If we get up to here,
it's 100%. That'd be 78% nitrogen.

123
00:07:23,440 --> 00:07:26,280
So, there's a lot of nitrogen
in the air, isn't there?

124
00:07:26,280 --> 00:07:28,680
There's all this. Look at this.
You've got to stop it.

125
00:07:28,680 --> 00:07:31,800
You've got to get this red mark
here on the black mark,

126
00:07:31,800 --> 00:07:33,560
so you've got to get this
just right.

127
00:07:33,560 --> 00:07:37,680
This is our nitrogen, and this is
going to be 78%.

128
00:07:39,000 --> 00:07:44,720
Oh, stop, stop, stop, stop, stop,
stop, stop! You've gone past. Sorry!

129
00:07:44,720 --> 00:07:48,120
Oh, dear, what a disaster.
That's OK. Look, there we are.

130
00:07:48,120 --> 00:07:50,640
There we are. Spot on.

131
00:07:50,640 --> 00:07:54,000
78%. Well done, that's fantastic.
Excellent. OK.

132
00:07:54,000 --> 00:07:57,000
Now then, the next ingredient,
what's the next ingredient?

133
00:07:57,000 --> 00:08:01,280
Nitrogen? Oh, sorry. We've done
nitrogen. What's the next one?

134
00:08:01,280 --> 00:08:04,640
Carbon dioxide. No. You like your
carbon dioxide. Oxygen. It's oxygen.

135
00:08:04,640 --> 00:08:07,080
You're absolutely right.
Very important one.

136
00:08:07,080 --> 00:08:11,160
Right. So this is our oxygen. OK?
You're absolutely right there.

137
00:08:11,160 --> 00:08:13,520
You ready to go again? Yeah.
Not yet, not yet.

138
00:08:13,520 --> 00:08:15,840
We've got to go to 21%.

139
00:08:15,840 --> 00:08:20,360
Now, 21%,
that takes us to about here,

140
00:08:20,360 --> 00:08:25,360
I think. OK, that's 21-ish. Yes.
So you're aiming for here, OK?

141
00:08:25,360 --> 00:08:27,200
Go on, then.

142
00:08:27,200 --> 00:08:29,640
That's it. Very good.

143
00:08:31,480 --> 00:08:34,160
So there's
quite a lot of oxygen as well.

144
00:08:34,160 --> 00:08:37,960
I can see the concentration now.
That's what we need. Very good.

145
00:08:37,960 --> 00:08:42,240
Oh, look at that.
Just about spot on again.

146
00:08:42,240 --> 00:08:45,200
Remarkable. OK. Very good.

147
00:08:45,200 --> 00:08:49,360
Now, then. Now, we're coming to
the third most abundant gas.

148
00:08:49,360 --> 00:08:55,040
So far, we've got 78% nitrogen,
we've got 21% oxygen.

149
00:08:55,040 --> 00:09:00,760
We've almost run out of everything
else. That's only 1% left.

150
00:09:00,760 --> 00:09:03,600
Does anyone know
the third most abundant gas?

151
00:09:03,600 --> 00:09:06,520
You haven't mentioned this one yet.
Does anybody know? Shout it out.

152
00:09:06,520 --> 00:09:08,040
SHOUTING

153
00:09:08,040 --> 00:09:12,000
All sorts of different replies
there, but it is, in fact, argon.

154
00:09:12,000 --> 00:09:14,720
I think some people said argon.
Pat yourself on the back there.

155
00:09:14,720 --> 00:09:16,040
It is argon. Right.

156
00:09:16,040 --> 00:09:18,400
This is a tricky one now,
but you're getting very good.

157
00:09:18,400 --> 00:09:22,560
All right. Argon. This is
just 1%, so that's about there.

158
00:09:22,560 --> 00:09:24,920
Can you see that? Yeah. About here,
here it is, OK?

159
00:09:24,920 --> 00:09:28,960
OK. Go on, then. Go on.

160
00:09:28,960 --> 00:09:32,400
Oh, wrong one. The audience
are watching. The argon one.

161
00:09:32,400 --> 00:09:35,160
That's it. Give it a go.

162
00:09:35,160 --> 00:09:36,680
Brilliant.

163
00:09:36,680 --> 00:09:40,320
There we are. Look at that. That is
very good indeed. Now, then.

164
00:09:40,320 --> 00:09:41,200
APPLAUSE

165
00:09:43,960 --> 00:09:47,400
We're coming to your favourite gas.
Which one's that? Carbon dioxide.

166
00:09:47,400 --> 00:09:50,200
Carbon dioxide, exactly. But there's
not a lot of carbon dioxide.

167
00:09:50,200 --> 00:09:54,920
In fact, it's 0.037% carbon dioxide.

168
00:09:54,920 --> 00:09:57,800
Unless we did this 200 years ago,
it would've been quite a bit less.

169
00:09:57,800 --> 00:09:59,720
We've increased the amount,
but anyway...

170
00:09:59,720 --> 00:10:03,680
So carbon dioxide, we just need
a quick burst from that, so
quick burst. That's it. That'll do.

171
00:10:03,680 --> 00:10:05,280
That's your carbon dioxide.

172
00:10:05,280 --> 00:10:08,520
Hardly any at all,
but nonetheless, very important.

173
00:10:08,520 --> 00:10:11,720
All the plants need that.
So that's our carbon dioxide.

174
00:10:11,720 --> 00:10:13,800
You still haven't made
perfect air yet.

175
00:10:13,800 --> 00:10:16,880
We could breathe this, that would be
OK, but there are some other gases,

176
00:10:16,880 --> 00:10:18,640
and these are some rather rare gases

177
00:10:18,640 --> 00:10:21,480
but we've put all of these
in this little syringe here.

178
00:10:21,480 --> 00:10:24,760
Would you like to just
add your last bit of gas,

179
00:10:24,760 --> 00:10:28,120
so just push the plunger down
and watch for the bubble.

180
00:10:28,120 --> 00:10:30,280
That it is, there we are.

181
00:10:30,280 --> 00:10:32,960
There, excellent.
That's the last gases.

182
00:10:32,960 --> 00:10:36,160
This is neon, helium,
krypton, and xenon.

183
00:10:36,160 --> 00:10:39,040
They make up just a tiny proportion
of the gas.

184
00:10:39,040 --> 00:10:40,600
You did very well there.

185
00:10:40,600 --> 00:10:43,160
Thank you very much.
Give her a big round of applause.

186
00:10:43,160 --> 00:10:48,920
APPLAUSE

187
00:10:49,960 --> 00:10:55,080
OK, so now then we know that air
isn't just one element,

188
00:10:55,080 --> 00:10:56,640
but a mixture of many.

189
00:10:56,640 --> 00:11:00,960
Before we look at these different
elements from air in more detail,

190
00:11:00,960 --> 00:11:03,760
we want to see all of the elements
that occur in nature.

191
00:11:03,760 --> 00:11:05,240
Now this is where you come in.

192
00:11:05,240 --> 00:11:07,800
You've got your cards here
for different elements

193
00:11:07,800 --> 00:11:10,320
so, if you're a member of
the periodic table, get ready,

194
00:11:10,320 --> 00:11:12,800
but to help us with this,
would you please welcome,

195
00:11:12,800 --> 00:11:17,400
straight from the West End,
the cast of the musical Loserville?

196
00:11:17,400 --> 00:11:23,520
APPLAUSE

197
00:11:27,360 --> 00:11:30,400
# There's antimony, arsenic,
aluminium, selenium

198
00:11:30,400 --> 00:11:32,640
# And hydrogen and oxygen
and nitrogen and rhenium

199
00:11:32,640 --> 00:11:34,880
# And nickel, neodymium,
neptunium, germanium

200
00:11:34,880 --> 00:11:36,720
# Iron, americium,
ruthenium, uranium

201
00:11:36,720 --> 00:11:38,840
# Europium, zirconium,
lutetium, vanadium

202
00:11:38,840 --> 00:11:41,000
# And lanthanum and osmium
and astatine and radium

203
00:11:41,000 --> 00:11:44,440
# And gold and protactinium
and indium and gallium

204
00:11:44,440 --> 00:11:48,200
# And iodine and thorium
and thulium and thallium

205
00:11:48,200 --> 00:11:51,120
# There's yttrium, ytterbium,
actinium, rubidium

206
00:11:51,120 --> 00:11:53,200
# And boron, gadolinium,
niobium, iridium

207
00:11:53,200 --> 00:11:55,400
# And strontium and silicon
and silver and samarium

208
00:11:55,400 --> 00:11:58,040
# And bismuth, bromine, lithium,
beryllium, and barium... #

209
00:11:58,040 --> 00:11:59,520
Barium - very good!

210
00:12:03,320 --> 00:12:05,920
# There's holmium and helium
and hafnium and erbium

211
00:12:05,920 --> 00:12:08,200
# And phosphorus and francium
and fluorine and terbium

212
00:12:08,200 --> 00:12:10,440
# And manganese and mercury,
molybdenum, magnesium

213
00:12:10,440 --> 00:12:12,640
# Dysprosium and scandium
and cerium and cesium

214
00:12:12,640 --> 00:12:14,920
# And lead, praseodymium
and platinum, plutonium

215
00:12:14,920 --> 00:12:16,960
# Palladium, promethium,
potassium, polonium

216
00:12:16,960 --> 00:12:20,400
# And tantalum, technetium,
titanium, tellurium,

217
00:12:20,400 --> 00:12:22,720
# And cadmium and calcium
and chromium and curium

218
00:12:24,280 --> 00:12:26,720
# There's sulphur, californium
and fermium, berkelium

219
00:12:26,720 --> 00:12:28,840
# And also mendelevium,
einsteinium, nobelium

220
00:12:28,840 --> 00:12:31,360
# And argon, krypton, neon, radon,
xenon, zinc and rhodium

221
00:12:31,360 --> 00:12:34,280
# And chlorine, carbon, cobalt,
copper, tungsten, tin and sodium

222
00:12:36,440 --> 00:12:41,120
# These were the only ones they found
back when this song was written

223
00:12:42,320 --> 00:12:46,640
# There are another 60 - now we'll
show you where they're sitting... #

224
00:12:46,640 --> 00:12:49,000
Stand up, as well? Excellent!

225
00:12:49,000 --> 00:12:52,840
APPLAUSE

226
00:12:54,320 --> 00:12:58,560
You did very well. My whole periodic
table should be standing now

227
00:12:58,560 --> 00:13:01,600
but would you please give a round of
applause for the cast of Loserville?

228
00:13:01,600 --> 00:13:06,080
Thank you very much.
APPLAUSE

229
00:13:06,080 --> 00:13:08,960
OK, well, that was certainly chaotic

230
00:13:08,960 --> 00:13:10,680
but you did fantastically well
there.

231
00:13:10,680 --> 00:13:13,400
If you'd like to take your seats.

232
00:13:13,400 --> 00:13:15,640
Now, what about this
sort of random order?

233
00:13:15,640 --> 00:13:19,080
You were springing up all over the
place. Was it really a random order?

234
00:13:19,080 --> 00:13:21,160
Well, actually, it's not.

235
00:13:21,160 --> 00:13:24,240
There is some logic behind this,
but to understand the logic

236
00:13:24,240 --> 00:13:27,560
we need to look
right into the heart of the atom.

237
00:13:27,560 --> 00:13:31,080
So atoms, as far as the chemists
are concerned at least,

238
00:13:31,080 --> 00:13:33,520
are made up of three
different particles.

239
00:13:33,520 --> 00:13:37,200
In the heart of the nucleus,
there are positively charged protons

240
00:13:37,200 --> 00:13:41,600
and neutral neutrons.
We can see these on the screen.

241
00:13:41,600 --> 00:13:44,520
So the red ones are the protons,
the blue ones are the neutrons.

242
00:13:44,520 --> 00:13:47,720
But then circling around,
we have these electrons.

243
00:13:47,720 --> 00:13:51,080
It's the protons and the neutrons
that give an element its mass,

244
00:13:51,080 --> 00:13:53,960
make it quite heavy, so if you pick
something up and say it's heavy,

245
00:13:53,960 --> 00:13:56,240
well, that's because
of the protons and neutrons.

246
00:13:56,240 --> 00:13:59,360
But it's these electrons that are
right around the outside,

247
00:13:59,360 --> 00:14:02,600
and whenever you touch anything,
what you're touching there is
electrons.

248
00:14:02,600 --> 00:14:06,600
I bet you've never thought of this
before, but if we shake hands
we're shaking electrons there.

249
00:14:06,600 --> 00:14:10,480
OK, that's our electrons touching
each other there. Anyway, right!

250
00:14:10,480 --> 00:14:12,000
So, here we have our atom.

251
00:14:12,000 --> 00:14:14,280
We now understand what atoms
are made of

252
00:14:14,280 --> 00:14:16,680
but what's that got to do
with the periodic table?

253
00:14:16,680 --> 00:14:21,680
Well, what makes an element unique
is the number of protons
in the atom.

254
00:14:21,680 --> 00:14:23,360
We don't really care
about the neutrons

255
00:14:23,360 --> 00:14:25,080
and if it's a neutral atom,

256
00:14:25,080 --> 00:14:28,160
of course the number of protons are
balanced by the number of electrons.

257
00:14:28,160 --> 00:14:31,600
Hydrogen, where are you? If you'd
like to stand up, hydrogen.

258
00:14:31,600 --> 00:14:33,440
You are the first element,

259
00:14:33,440 --> 00:14:36,680
in fact the most abundant
element in the universe.

260
00:14:36,680 --> 00:14:40,000
You've got one proton.
That's what makes you hydrogen.

261
00:14:40,000 --> 00:14:44,240
One proton and one electron for
the neutral atom. Sometimes neutrons
but we don't care about those.

262
00:14:44,240 --> 00:14:47,440
The next element, on the same row,
we go all the way round to here

263
00:14:47,440 --> 00:14:52,160
and we find helium. You have two
protons - that's what makes you you.

264
00:14:52,160 --> 00:14:56,760
Then we come back over here to the
periodic table. You're very good.

265
00:14:56,760 --> 00:14:59,960
Lithium, you've got three protons
and that's what makes you you,
and so on.

266
00:14:59,960 --> 00:15:02,600
That's what we do when we go
from one element to the next.

267
00:15:02,600 --> 00:15:05,520
We increase the number of protons
by one and the number of electrons

268
00:15:05,520 --> 00:15:08,240
in the neutral atom,
and maybe throw in a few neutrons.

269
00:15:08,240 --> 00:15:12,200
Now, the question is, though,
we've got 118 elements

270
00:15:12,200 --> 00:15:17,080
but we've got literally tens
of millions of different compounds

271
00:15:17,080 --> 00:15:23,160
so how can we get such complexity
out of just these 118 elements?

272
00:15:23,160 --> 00:15:26,280
In fact,
in this cup of coffee alone,

273
00:15:26,280 --> 00:15:30,320
over 2,000 different compounds
have been detected so far -

274
00:15:30,320 --> 00:15:35,080
so loads of compounds,
only 118 elements.

275
00:15:35,080 --> 00:15:40,680
There's a nice analogy between
letters and words with these
elements and their compounds

276
00:15:40,680 --> 00:15:44,400
so I could be saying hundreds
of thousands of different words now

277
00:15:44,400 --> 00:15:48,400
but these are all made up of the
same 26 letters of the alphabet.

278
00:15:48,400 --> 00:15:53,240
Words like "I" and "a"
are made up with a single letter.

279
00:15:53,240 --> 00:15:55,720
There are some words that have
two of the same letter.

280
00:15:55,720 --> 00:15:59,040
Aa is a type of Hawaiian lava.

281
00:15:59,040 --> 00:16:02,400
What a silly word that is. But then
there's another Hawaiian word.

282
00:16:02,400 --> 00:16:04,880
This is aaa, or something like that,

283
00:16:04,880 --> 00:16:08,320
which is an insect
also found in Hawaii.

284
00:16:09,760 --> 00:16:11,720
Our elements have
the same sort of thing.

285
00:16:11,720 --> 00:16:14,000
The letters then correspond
to the elements,

286
00:16:14,000 --> 00:16:18,640
and there are some elements
that just stay by themselves,
like these letters.

287
00:16:18,640 --> 00:16:22,920
Helium, can you put your card up,
please? Where are you? There you
are. And neon, and argon.

288
00:16:22,920 --> 00:16:25,280
All of you,
you just stay by yourselves,

289
00:16:25,280 --> 00:16:27,720
just single letters if you like.
Single elements.

290
00:16:27,720 --> 00:16:31,840
Then we have other elements that go
around in pairs. Where's nitrogen?
Put your card up.

291
00:16:31,840 --> 00:16:34,400
Oxygen, fluorine,
all of you go around in pairs.

292
00:16:34,400 --> 00:16:38,000
Chlorine, you go around in pairs
as well, so you go around in pairs

293
00:16:38,000 --> 00:16:41,840
and occasionally oxygen - just stand
up again, oxygen - occasionally

294
00:16:41,840 --> 00:16:45,240
you have three oxygen atoms that
make up a molecule of ozone.

295
00:16:45,240 --> 00:16:47,080
OK, thank you very much, elements.

296
00:16:47,080 --> 00:16:48,760
But most of the periodic table,

297
00:16:48,760 --> 00:16:53,640
you are loads of these single atoms
together, joined together to form

298
00:16:53,640 --> 00:16:57,920
big masses of metal or non-metals,
or whatever you are,
if you're solid.

299
00:16:57,920 --> 00:17:00,920
So this would be like a word
like "aaaaa" going on for ever,

300
00:17:00,920 --> 00:17:03,280
with so many letters
we couldn't count them.

301
00:17:03,280 --> 00:17:05,360
That's not how we usually
find the elements.

302
00:17:05,360 --> 00:17:06,640
How we usually find them

303
00:17:06,640 --> 00:17:10,480
is combined with one another
to form compounds

304
00:17:10,480 --> 00:17:14,040
so if the letters correspond
to our elements,

305
00:17:14,040 --> 00:17:15,960
the words that we use,

306
00:17:15,960 --> 00:17:20,400
these correspond to different
combinations of the elements -
these are the compounds.

307
00:17:20,400 --> 00:17:25,440
So, the elements want to combine
with one another to form different

308
00:17:25,440 --> 00:17:28,360
molecules and we are going to try
an experiment now to show this,

309
00:17:28,360 --> 00:17:31,160
to show the combination
of two elements

310
00:17:31,160 --> 00:17:34,120
and this is the element oxygen,
one of the elements from the air.

311
00:17:34,120 --> 00:17:35,280
Oxygen, where are you again?

312
00:17:35,280 --> 00:17:38,280
There's oxygen. And between
phosphorus. Phosphorus.

313
00:17:38,280 --> 00:17:40,320
Can you please stand up, phosphorus.

314
00:17:40,320 --> 00:17:45,760
OK, now, do you know how you were
first discovered, phosphorus? No.

315
00:17:45,760 --> 00:17:48,760
OK, well, we'll give you a bit
of a clue. What's your symbol?

316
00:17:48,760 --> 00:17:50,080
P.

317
00:17:50,080 --> 00:17:54,400
P. Any idea? No?
Does anyone else know?

318
00:17:54,400 --> 00:17:56,360
OK, there's a chap
right at the back there.

319
00:17:56,360 --> 00:18:00,000
So where do you think phosphorus
was first discovered? From wee.

320
00:18:00,000 --> 00:18:01,840
From wee, yes, exactly.

321
00:18:01,840 --> 00:18:04,680
OK, so thank you, phosphorus.
You can take a seat now.

322
00:18:04,680 --> 00:18:09,040
I've got some urine here -
it's only mine so it's not too bad.

323
00:18:09,040 --> 00:18:10,920
AUDIENCE: Eurgh!

324
00:18:10,920 --> 00:18:13,560
It's all right! Smells quite nice.

325
00:18:13,560 --> 00:18:15,640
Do you want a sniff? Oh, you do! OK!

326
00:18:15,640 --> 00:18:18,800
LAUGHTER

327
00:18:18,800 --> 00:18:21,920
It's fine!

328
00:18:21,920 --> 00:18:23,960
Don't worry -
it's only apple juice, really!

329
00:18:23,960 --> 00:18:26,200
But...OK,

330
00:18:26,200 --> 00:18:29,760
but back in 1669,

331
00:18:29,760 --> 00:18:34,680
the German alchemist Hennig Brand
did take his own urine

332
00:18:34,680 --> 00:18:38,800
and he heated this up
and this amazing substance came out.

333
00:18:38,800 --> 00:18:42,680
This was phosphorus. How come
phosphorus was discovered so early?

334
00:18:42,680 --> 00:18:44,840
Not just because it was disgusting,

335
00:18:44,840 --> 00:18:47,560
but also because once you found it
you couldn't miss it.

336
00:18:47,560 --> 00:18:51,120
It just screams out to you,
"Here I am!"

337
00:18:51,120 --> 00:18:52,640
OK, let's try this.

338
00:18:52,640 --> 00:18:54,680
We've got some phosphorus
in this flask here

339
00:18:54,680 --> 00:18:56,760
and I'm just going to
let the air into this.

340
00:18:56,760 --> 00:18:59,920
We've removed the air
and heated up the phosphorus,

341
00:18:59,920 --> 00:19:01,560
and watch what happens here.

342
00:19:01,560 --> 00:19:04,400
Maybe we can have the lights down
just a little bit here.

343
00:19:06,440 --> 00:19:11,880
So, as soon as the air comes in,
it combines with the phosphorus.

344
00:19:15,960 --> 00:19:20,120
This is phosphorus
reacting with air,

345
00:19:20,120 --> 00:19:23,720
and this amazed the alchemists.

346
00:19:23,720 --> 00:19:26,560
When they saw this,
they were truly stunned.

347
00:19:26,560 --> 00:19:30,000
In fact, they were so impressed
by this amazing light

348
00:19:30,000 --> 00:19:34,240
that the reaction has given out,
they named this element phosphorus,

349
00:19:34,240 --> 00:19:37,960
which means "the light giver".

350
00:19:37,960 --> 00:19:45,720
This discovery was commemorated
with a painting by Joseph Wright
of Derby, that's on the screen here.

351
00:19:45,720 --> 00:19:48,040
It has a really catchy title.

352
00:19:48,040 --> 00:19:51,960
It's called "the alchemist in search
of the philosopher's stone

353
00:19:51,960 --> 00:19:55,640
"discovers phosphorus and prays
for the successful conclusion

354
00:19:55,640 --> 00:20:01,680
"of his operation,
as was the custom of the ancient
chemical astrologers".

355
00:20:01,680 --> 00:20:05,240
Snappy, but it sort of says what
it is, and you can see this,

356
00:20:05,240 --> 00:20:10,200
this amazing look in the alchemist's
eyes as he's made
this fantastic discovery.

357
00:20:10,200 --> 00:20:13,760
This was far brighter than any of
their lamps or candles at the time.

358
00:20:13,760 --> 00:20:18,520
I have a description here.
This is from a book from 1692.

359
00:20:18,520 --> 00:20:19,800
It describes phosphorus.

360
00:20:19,800 --> 00:20:22,800
It says you need to store it
underwater because
it reacts with the air,

361
00:20:22,800 --> 00:20:24,240
but it also says here,

362
00:20:24,240 --> 00:20:30,720
"If the Privy Parts be therewith
rubb'd, they will be inflamed and
burning a good while after."

363
00:20:32,160 --> 00:20:36,120
Now there's one that you really
shouldn't try at home!

364
00:20:36,120 --> 00:20:42,120
Please don't go smearing phosphorus
on your privy parts. It's not fun.

365
00:20:42,120 --> 00:20:47,400
Anyway, but the alchemists made this
discovery. They found phosphorus.

366
00:20:47,400 --> 00:20:49,960
They knew it was reacting
with the air

367
00:20:49,960 --> 00:20:52,280
but they didn't understand
fully what was going on

368
00:20:52,280 --> 00:20:55,720
because they didn't know
what the air was made of.

369
00:20:56,920 --> 00:20:59,960
Chemists now know
that it's a mixture of gases

370
00:20:59,960 --> 00:21:02,440
and a mixture of different elements
that makes up the air.

371
00:21:02,440 --> 00:21:06,680
Now, we're going to have
a look again at the different gases
that are in the air.

372
00:21:06,680 --> 00:21:10,120
In fact, first of all, can we have
all the elements that are gases?

373
00:21:10,120 --> 00:21:12,360
So, all the gaseous atoms.
Can you stand up, please?

374
00:21:12,360 --> 00:21:16,560
So, where are all the atoms that are
gases? We have hydrogen over here.

375
00:21:16,560 --> 00:21:19,240
Well, it's a good job there's not
too much of you in the air

376
00:21:19,240 --> 00:21:22,320
because that would make it very
flammable, so if you sit down.

377
00:21:22,320 --> 00:21:24,520
It would all explode
if there was too much hydrogen

378
00:21:24,520 --> 00:21:26,560
and that wouldn't be very
good at all. Who else?

379
00:21:26,560 --> 00:21:29,040
Nitrogen and oxygen, we know
you're the major components,

380
00:21:29,040 --> 00:21:31,080
but we've also got fluorine
and chlorine.

381
00:21:31,080 --> 00:21:33,480
Fluorine and chlorine,
you are incredibly reactive,

382
00:21:33,480 --> 00:21:36,800
which also makes you incredibly
toxic so it's a very good thing

383
00:21:36,800 --> 00:21:40,600
that you're not in the air as well
so perhaps you can sit down as well,
please.

384
00:21:40,600 --> 00:21:43,640
Look where the gases
that we do find in the air are.

385
00:21:43,640 --> 00:21:46,400
We've got nitrogen and oxygen,
we've seen you, but then we've got

386
00:21:46,400 --> 00:21:50,160
all of you sitting here -
well, standing here -
with the white cards.

387
00:21:50,160 --> 00:21:54,840
You are the so-called noble gases.
Why are you all sitting together?

388
00:21:54,840 --> 00:21:59,320
This is not a coincidence, it's
because you all have very similar

389
00:21:59,320 --> 00:22:03,080
chemical properties and there's this
amazing pattern when we arrange

390
00:22:03,080 --> 00:22:06,520
the elements in a certain way,
that every so often

391
00:22:06,520 --> 00:22:10,800
elements with the same chemical
properties are found
grouped together.

392
00:22:10,800 --> 00:22:13,720
So if we just have our periodic
tables up, please.

393
00:22:13,720 --> 00:22:16,080
That's it, fantastic, very good.

394
00:22:16,080 --> 00:22:18,400
We can see these coloured patterns
here.

395
00:22:18,400 --> 00:22:20,840
What a beautiful display this is.
Excellent.

396
00:22:20,840 --> 00:22:23,440
All of you with the purple cards
here, you are group one.

397
00:22:23,440 --> 00:22:27,400
You're all really reactive metals,
you explode with water.

398
00:22:27,400 --> 00:22:29,400
Really violently, OK?

399
00:22:29,400 --> 00:22:32,400
You all have similar properties,
you're all grouped together.

400
00:22:32,400 --> 00:22:35,040
If we come over here, all you with
the green cards for instance,

401
00:22:35,040 --> 00:22:36,680
you're called the halogens.

402
00:22:36,680 --> 00:22:39,520
You're really poisonous,
rather unpleasant substances,

403
00:22:39,520 --> 00:22:42,120
but you combine with these over here
with the alkali metals,

404
00:22:42,120 --> 00:22:45,400
and you form salts
very violently indeed.

405
00:22:45,400 --> 00:22:47,520
OK, at ease, periodic table.

406
00:22:47,520 --> 00:22:51,120
We're going to look, though,
at our noble gases.

407
00:22:51,120 --> 00:22:55,800
So, if everyone sits down, but I'd
like the noble gases now
to come down to the front.

408
00:22:55,800 --> 00:23:01,000
We've got some samples for you.
A balloon of krypton.

409
00:23:01,000 --> 00:23:03,200
Hold the string and hold it out.
Beautiful.

410
00:23:03,200 --> 00:23:06,840
OK. Xenon, again, hold the string,
there we are.

411
00:23:06,840 --> 00:23:11,800
And then we come... Ah! We have
a slight problem with radon,
I'm afraid.

412
00:23:11,800 --> 00:23:14,120
Radon is incredibly radioactive

413
00:23:14,120 --> 00:23:17,920
so health and safety wouldn't let us
give you a balloon full of radon.

414
00:23:17,920 --> 00:23:22,760
You would go home glowing, so we'll
just put this one on you there.

415
00:23:22,760 --> 00:23:24,000
That's great.

416
00:23:26,440 --> 00:23:30,600
And ununoctium, I'm afraid
ununoctium hasn't even got a name

417
00:23:30,600 --> 00:23:35,200
and this is because there's so few
atoms of ununoctium that were made,

418
00:23:35,200 --> 00:23:37,240
or we're not even sure
if they were made,

419
00:23:37,240 --> 00:23:40,440
but we couldn't fill a balloon
full of you. But you got
a balloon anyway!

420
00:23:40,440 --> 00:23:44,920
LAUGHTER

421
00:23:44,920 --> 00:23:48,160
OK, so, mm-hmm, right.

422
00:23:48,160 --> 00:23:49,840
Now, you've all got your balloons

423
00:23:49,840 --> 00:23:53,600
and after a countdown from three,
I'd like you to release
your balloons.

424
00:23:53,600 --> 00:23:56,880
Keep hold of the strings, though,
and we'll see what happens.

425
00:23:56,880 --> 00:23:58,080
So three, two, one, go.

426
00:23:59,560 --> 00:24:02,080
Ah! Look at that.
Now, what do we see here?

427
00:24:02,080 --> 00:24:04,520
We all know
that helium balloons float

428
00:24:04,520 --> 00:24:08,280
so you've got a nice light element
there, helium. What about this neon?

429
00:24:08,280 --> 00:24:13,320
Neon, hmm, it's about the same.
You've dropped your string.

430
00:24:13,320 --> 00:24:17,640
Keep hold of the string. It's about
the same sort of density as air.

431
00:24:17,640 --> 00:24:23,120
It's the balloon that's making
it sink. Argon is getting pretty,
er... Whoops! More dense there.

432
00:24:23,120 --> 00:24:27,200
Keep hold, thank you.
Krypton is really quite heavy.

433
00:24:27,200 --> 00:24:31,960
And xenon, hmm, you wouldn't want to
go to a party with that, would you?

434
00:24:31,960 --> 00:24:34,040
You would be dragging
this along the floor!

435
00:24:34,040 --> 00:24:36,920
It's a very expensive gas -
it's about £100, this balloon,

436
00:24:36,920 --> 00:24:41,000
but yes, it's very heavy indeed.
What does this tell us, though?

437
00:24:41,000 --> 00:24:45,720
Each of these balloons actually
has the same number of atoms

438
00:24:45,720 --> 00:24:48,960
because equal volumes contain
the same number of particles.

439
00:24:48,960 --> 00:24:56,360
It tells us that the atoms of helium
are much lighter
than the atoms of xenon

440
00:24:56,360 --> 00:24:59,640
and that's because of the subatomic
particles that make up these atoms.

441
00:24:59,640 --> 00:25:03,120
The helium just has two protons
and two neutrons

442
00:25:03,120 --> 00:25:07,200
all the way down to ununoctium -
you have 118 protons
and loads of neutrons.

443
00:25:07,200 --> 00:25:09,200
I think you've done
fantastically well.

444
00:25:09,200 --> 00:25:11,600
Would you like to return
to your seats? Thank you.

445
00:25:11,600 --> 00:25:14,680
APPLAUSE

446
00:25:14,680 --> 00:25:17,520
We've seen that we've got different
densities of these gases,

447
00:25:17,520 --> 00:25:18,760
they have different masses,

448
00:25:18,760 --> 00:25:21,680
but they also have
very similar properties

449
00:25:21,680 --> 00:25:24,640
and each of these elements is a gas

450
00:25:24,640 --> 00:25:28,000
and we've filled these signs up
with these gases.

451
00:25:28,000 --> 00:25:29,520
We can see that
you're all colourless.

452
00:25:29,520 --> 00:25:33,080
You're also all odourless gases,
which is a good thing.

453
00:25:33,080 --> 00:25:36,360
You don't smell at all,
but not very exciting to look at,

454
00:25:36,360 --> 00:25:40,360
until you pass a few thousand
volts through you.
Watch what happens then.

455
00:25:40,360 --> 00:25:43,120
They all become much prettier.

456
00:25:43,120 --> 00:25:46,800
This is the normal neon
signs that we see.

457
00:25:46,800 --> 00:25:50,840
This sign here is filled with neon
gas, but when it gets excited

458
00:25:50,840 --> 00:25:53,680
with the electricity there,
the electrons are leaping up,

459
00:25:53,680 --> 00:25:57,560
and as they come back down
we get this fantastic red colour.

460
00:25:57,560 --> 00:26:00,200
Each element has its own
unique colour

461
00:26:00,200 --> 00:26:03,360
so we can see, then,
that some of these gases have uses.

462
00:26:03,360 --> 00:26:05,480
Neon is used in neon signs.

463
00:26:05,480 --> 00:26:11,200
But some of them have even more
important uses, and I went to the

464
00:26:11,200 --> 00:26:15,440
University of Sheffield to have a
look at one of the uses for helium.

465
00:26:17,280 --> 00:26:20,960
So what's in this little bag
here that I've got then, Jim?

466
00:26:20,960 --> 00:26:25,440
What you've got in there
is essentially a bag
with some helium atoms,

467
00:26:25,440 --> 00:26:29,240
which are magnetically
aligned or polarised.

468
00:26:29,240 --> 00:26:31,680
They are contained within the bag.

469
00:26:31,680 --> 00:26:33,680
If we were to actually image
the bag, you'd see

470
00:26:33,680 --> 00:26:37,240
just the boundaries of the bag
and the air space inside the bag

471
00:26:37,240 --> 00:26:40,840
filled with the gas and nothing
on the outside and, similarly,

472
00:26:40,840 --> 00:26:44,480
when you breathe it in we will
see the gas inside your lungs.

473
00:26:44,480 --> 00:26:48,160
The scanner is actually a giant
magnet with radio detectors

474
00:26:48,160 --> 00:26:52,480
which detect the specially prepared
helium atoms as they return

475
00:26:52,480 --> 00:26:54,760
to their natural state
within this magnet.

476
00:26:54,760 --> 00:26:59,760
This allows Jim
to build up a picture of where
the gases are in my lungs.

477
00:26:59,760 --> 00:27:02,560
Your scan is here.
Those are my lungs?

478
00:27:04,000 --> 00:27:07,560
There's your bronchus, trachea,
and your two bronchi,

479
00:27:07,560 --> 00:27:09,440
main feeding bronchi
coming off the bronchus.

480
00:27:09,440 --> 00:27:10,840
These are your blood vessels.

481
00:27:10,840 --> 00:27:14,960
So the amazing thing about this
is that we are only seeing

482
00:27:14,960 --> 00:27:18,160
the air inside my lungs,
aren't we? Exactly.

483
00:27:18,160 --> 00:27:21,240
You're just visualising
the air spaces there.

484
00:27:21,240 --> 00:27:24,680
It's very exciting to be
looking at my own lungs!

485
00:27:24,680 --> 00:27:26,960
It's nice to know they're not
too bad, even though

486
00:27:26,960 --> 00:27:29,680
I know I've got a bit of a cough
at the moment.

487
00:27:29,680 --> 00:27:34,320
Nonetheless, they're reasonably
healthy, you think? They look pretty
healthy. That's all right, then.

488
00:27:34,320 --> 00:27:36,360
So this is pretty cutting-edge
science here.

489
00:27:36,360 --> 00:27:40,120
We're actually using this
form of helium, helium three,

490
00:27:40,120 --> 00:27:43,680
to image the workings,
how our lung works.

491
00:27:43,680 --> 00:27:47,040
And actually on the screen we
can see here, these are two lungs.

492
00:27:47,040 --> 00:27:51,280
This is a lung of a patient who has
asthma on the left-hand side here.

493
00:27:51,280 --> 00:27:52,920
You can see some black regions.

494
00:27:52,920 --> 00:27:57,600
But after they've taken their
inhaler, the lungs have opened up,

495
00:27:57,600 --> 00:28:01,040
the airways have opened up, and the
helium has gone into those regions.

496
00:28:01,040 --> 00:28:04,480
We can see all the places
where the air is now reaching.

497
00:28:04,480 --> 00:28:07,560
So this just shows
the medicine in action.

498
00:28:07,560 --> 00:28:12,520
OK, now, it's not just helium
that has exciting properties.

499
00:28:12,520 --> 00:28:15,760
If we go right the way down to the
bottom of the periodic table here,

500
00:28:15,760 --> 00:28:18,000
the heavy stable element xenon,

501
00:28:18,000 --> 00:28:20,840
this has some truly remarkable
properties as well.

502
00:28:20,840 --> 00:28:25,360
We have a tank here and we've filled
this with some xenon, I understand.
A little, yes.

503
00:28:25,360 --> 00:28:28,800
A little xenon so we just keep
putting a little bit more in there

504
00:28:28,800 --> 00:28:35,160
and I have a very delicate,
very fragile foil boat.

505
00:28:37,240 --> 00:28:40,440
I'm going to see if we can
actually balance this,

506
00:28:40,440 --> 00:28:44,800
if we can float this on the xenon
in this tank.

507
00:28:44,800 --> 00:28:47,560
Try this one.
Shall we try this one first?

508
00:28:47,560 --> 00:28:51,000
Yes, we'll try our new boat.
Just slide this over.

509
00:28:56,600 --> 00:29:00,040
And try our new boat.

510
00:29:00,040 --> 00:29:03,040
Ah! That's it. Look at that.

511
00:29:03,040 --> 00:29:06,440
That really is...
APPLAUSE

512
00:29:06,440 --> 00:29:09,280
..floating on the xenon.

513
00:29:11,440 --> 00:29:15,160
There are no strings.
It's a little bit fragile here.

514
00:29:15,160 --> 00:29:18,640
I think I need a volunteer to just
come and very carefully help me

515
00:29:18,640 --> 00:29:21,280
add some weight into this.

516
00:29:21,280 --> 00:29:26,160
We'll have somebody from, er, the...
Yes, right on the end.

517
00:29:26,160 --> 00:29:29,000
Would you like to come down?
Thank you.

518
00:29:31,640 --> 00:29:34,400
OK, thank you very much.
Give her a round of applause.

519
00:29:34,400 --> 00:29:37,520
If you'd like to come round here.

520
00:29:37,520 --> 00:29:40,640
I'm just trying to keep my boat
level here.

521
00:29:40,640 --> 00:29:43,800
Just add a little bit more xenon.
What's your name, please? Bethany.

522
00:29:43,800 --> 00:29:45,600
Bethany, excellent.

523
00:29:45,600 --> 00:29:48,480
Now, you are going to be probably
the first person in the world

524
00:29:48,480 --> 00:29:50,920
ever to try this -
we haven't even practised this.

525
00:29:50,920 --> 00:29:55,400
Have a look at this.
What do you think this is? Hold it.

526
00:29:55,400 --> 00:29:59,080
Foil. It's foil.
Does it feel like normal foil? No.

527
00:29:59,080 --> 00:30:02,920
No, it feels strange, doesn't it?
That's because it's pure solid gold.

528
00:30:02,920 --> 00:30:04,520
Right?

529
00:30:04,520 --> 00:30:07,000
This is pure solid gold so let's
just screw it up a little bit

530
00:30:07,000 --> 00:30:09,000
and I'd like you
to put this in here.

531
00:30:09,000 --> 00:30:10,680
Just see if you can put it
in that corner.

532
00:30:10,680 --> 00:30:14,320
That corner is a little bit unstable
at the moment. That's it.
Oh, look at that!

533
00:30:14,320 --> 00:30:17,320
Now you have made this thing float
perfectly. That's pretty amazing.

534
00:30:17,320 --> 00:30:19,760
Add some more. Will you sink it?

535
00:30:21,120 --> 00:30:22,640
Not quite. Oh, there it goes.

536
00:30:22,640 --> 00:30:25,240
Fantastic! A world first.

537
00:30:25,240 --> 00:30:27,360
Thank you very much, excellent.

538
00:30:27,360 --> 00:30:31,760
APPLAUSE

539
00:30:31,760 --> 00:30:37,520
OK, xenon is very dense and I'm very
pleased that worked, but it also has

540
00:30:37,520 --> 00:30:41,960
some really remarkable properties
that can be used in medicine.

541
00:30:41,960 --> 00:30:45,160
Now, while I was at
the University of Sheffield,

542
00:30:45,160 --> 00:30:48,840
we took a chance to experience
what it's like to breathe in

543
00:30:48,840 --> 00:30:52,080
some xenon and it has very
strange effects on the body

544
00:30:52,080 --> 00:30:56,600
but it can be very useful as well,
so let's just see what happens here.

545
00:30:56,600 --> 00:31:00,800
If you take a deep breath in, Peter.
Breathe out.

546
00:31:00,800 --> 00:31:02,240
Deep breath in.

547
00:31:04,680 --> 00:31:08,400
Breathe out,
and now breathe from the bag. OK.

548
00:31:08,400 --> 00:31:11,600
Breathe in, breathe in, breathe in,
breathe in, breathe in, breathe in,

549
00:31:11,600 --> 00:31:16,240
breathe in, breathe in, breathe in,
breathe in, breathe in, breathe in.

550
00:31:16,240 --> 00:31:18,240
OK, and hold your breath.

551
00:31:21,360 --> 00:31:23,560
It will be interesting
if you talk as you breathe out,

552
00:31:23,560 --> 00:31:25,800
we'll see if we can hear the, er...

553
00:31:28,040 --> 00:31:30,560
DEEP VOICE: That's amazing.
I feel really relaxed

554
00:31:30,560 --> 00:31:33,720
and I can hear that my voice
has changed.

555
00:31:33,720 --> 00:31:38,600
It's gone quite deep now
but I feel very happy and relaxed

556
00:31:38,600 --> 00:31:40,600
and calm. Oh, it's wearing off now.

557
00:31:40,600 --> 00:31:45,920
Wow, so that's xenon,
these individual atoms of xenon,

558
00:31:45,920 --> 00:31:48,960
interacting with my brain
in some way, isn't it? Mmm.

559
00:31:48,960 --> 00:31:52,640
So it's going into my bloodstream
and interacting with my brain

560
00:31:52,640 --> 00:31:55,480
and making me feel slightly
light-headed. Mmm. And that's...

561
00:31:55,480 --> 00:31:58,520
At higher concentrations,
that acts as an anaesthetic

562
00:31:58,520 --> 00:32:00,120
and I would just pass out,
is that right?

563
00:32:00,120 --> 00:32:02,760
People do use it as an anaesthetic
in a clinical setting,

564
00:32:02,760 --> 00:32:05,200
but clearly at higher
concentrations than these.

565
00:32:05,200 --> 00:32:08,440
If we'd have retuned the scanner
slightly, we'd have actually seen

566
00:32:08,440 --> 00:32:11,000
the xenon atoms dissolved
in your blood as well.

567
00:32:11,000 --> 00:32:13,160
That's where we're going
with this at the moment.

568
00:32:13,160 --> 00:32:15,720
We'd love to actually be able
to pick up the xenon

569
00:32:15,720 --> 00:32:18,440
dissolved in the brain
and image the xenon in the brain.

570
00:32:18,440 --> 00:32:20,440
That might give us
some insight into how these

571
00:32:20,440 --> 00:32:23,840
anaesthetics are actually
working in the neural system.

572
00:32:23,840 --> 00:32:25,800
Incredible. Yeah.

573
00:32:25,800 --> 00:32:29,880
Now, that was certainly very strange
when I was breathing in this gas

574
00:32:29,880 --> 00:32:34,200
and the latest research that Jim
is doing allows the individual atoms

575
00:32:34,200 --> 00:32:37,320
of xenon to be followed
around the brain, even.

576
00:32:37,320 --> 00:32:41,400
Now, I'd like you to welcome three
incredibly important guests

577
00:32:41,400 --> 00:32:46,400
to the RI. Would you please welcome
Dave, Sarah and Riley Joyce?

578
00:32:46,400 --> 00:32:50,600
APPLAUSE

579
00:32:50,600 --> 00:32:52,720
Good to see you.

580
00:32:52,720 --> 00:32:55,080
Thank you very much. Hello.
Thank you.

581
00:32:55,080 --> 00:32:58,920
Ah! He's very shy in front
of the cameras here.

582
00:32:58,920 --> 00:33:01,280
I was wondering if...
Could you tell me your middle name?

583
00:33:01,280 --> 00:33:04,120
What's your full name?
Can you tell me your full name?

584
00:33:04,120 --> 00:33:08,160
A bit shy. He's a bit shy, but what
is his full name, then, please?

585
00:33:08,160 --> 00:33:12,040
It's Riley Xenon Joyce.
I think this is great.

586
00:33:12,040 --> 00:33:15,680
I would love to have an element
for a middle name, I must say.

587
00:33:15,680 --> 00:33:19,120
So why is Riley's middle name
Xenon, then?

588
00:33:19,120 --> 00:33:23,200
Well, Riley was the first
baby in the world to receive xenon,

589
00:33:23,200 --> 00:33:27,280
and he received it at St Michael's
in Bristol,

590
00:33:27,280 --> 00:33:30,720
due to when he was born
he didn't have a pulse

591
00:33:30,720 --> 00:33:34,320
and they had to resuscitate him
so he was starved of oxygen.

592
00:33:34,320 --> 00:33:38,720
This could have caused complications
if he didn't get this
treatment at the time,

593
00:33:38,720 --> 00:33:41,160
so this was acting
as an anaesthetic.

594
00:33:41,160 --> 00:33:46,640
Would it just gently put him to
sleep and allow the metabolism
to slow down?

595
00:33:46,640 --> 00:33:50,160
It has given his brain time to
recover and he had it alongside

596
00:33:50,160 --> 00:33:54,040
the head-cooling treatment,
which works on the same principle.

597
00:33:54,040 --> 00:33:57,560
I must say that he's very shy
at the moment in front of everybody

598
00:33:57,560 --> 00:33:59,960
but earlier he was running around
all over the place

599
00:33:59,960 --> 00:34:04,160
so he's clearly perfectly healthy
now, isn't he? Is that right? He is.

600
00:34:04,160 --> 00:34:07,800
In March this year
he had his two-year check-up

601
00:34:07,800 --> 00:34:12,120
and he was discharged as a
perfectly normal, healthy child.

602
00:34:12,120 --> 00:34:16,000
When he was born, he was given
a 50% chance of having
permanent brain damage

603
00:34:16,000 --> 00:34:19,880
so to come from there to where
we are now is incredible.

604
00:34:19,880 --> 00:34:22,120
That is absolutely fantastic.

605
00:34:22,120 --> 00:34:25,360
So would you please thank them
for coming in?

606
00:34:25,360 --> 00:34:30,640
APPLAUSE

607
00:34:33,600 --> 00:34:36,200
If we just have our periodic
table up for a moment.

608
00:34:36,200 --> 00:34:38,760
Have our periodic table up.

609
00:34:38,760 --> 00:34:41,400
We've seen that we
have our noble gases here.

610
00:34:41,400 --> 00:34:43,280
You're all individual atoms,

611
00:34:43,280 --> 00:34:46,240
you don't really want
to combine with the others,

612
00:34:46,240 --> 00:34:49,160
but this isn't the same throughout
the periodic table as a whole.

613
00:34:49,160 --> 00:34:52,200
We're trying to understand what
makes some of the gases in the air
so special,

614
00:34:52,200 --> 00:34:55,520
but in order to understand these,
how they're bonding with each other,

615
00:34:55,520 --> 00:34:58,840
we need to look across
the periodic table as a whole.

616
00:34:58,840 --> 00:35:01,520
I have a sample of one
of the elements here.

617
00:35:01,520 --> 00:35:04,520
This is the element potassium.
Potassium, can you stand up?

618
00:35:04,520 --> 00:35:05,800
There you are.

619
00:35:05,800 --> 00:35:09,480
So you're in this first group,
the same group as lithium, sodium,
potassium. Thank you.

620
00:35:09,480 --> 00:35:13,600
You're a solid, and in here
we have the solid potassium.

621
00:35:14,920 --> 00:35:19,040
Potassium is a metal,
and we've got this in the flask.

622
00:35:19,040 --> 00:35:22,480
At ease, periodic table. Thank you.
Cards down. Very good.

623
00:35:22,480 --> 00:35:28,920
We've got a little piece of
potassium here, and we've taken
the air out of this flask.

624
00:35:31,400 --> 00:35:35,040
And I'm just going to gently
warm the flask up.

625
00:35:37,560 --> 00:35:39,800
So potassium is a metal.

626
00:35:39,800 --> 00:35:43,440
The potassium atoms
want to bond to each other

627
00:35:43,440 --> 00:35:45,800
but they don't bond to each
other very tightly.

628
00:35:45,800 --> 00:35:49,760
So it is a solid, though,
not a gas like our noble gases,

629
00:35:49,760 --> 00:35:53,480
but watch what happens
if I just warm it up rather gently.

630
00:35:53,480 --> 00:35:57,360
Potassium is... Oh, look at that.

631
00:35:57,360 --> 00:36:01,440
What's happened here, all of the
potassium atoms have separated

632
00:36:01,440 --> 00:36:05,840
from each other and given this
fantastic coating over the inside.

633
00:36:05,840 --> 00:36:09,800
In fact, we've made an instant
Christmas bauble, which is great!

634
00:36:09,800 --> 00:36:12,520
But this is a Christmas bauble
coated with potassium,

635
00:36:12,520 --> 00:36:15,880
which is probably not so great.
But anyway, very beautiful,

636
00:36:15,880 --> 00:36:19,800
but we didn't need to put a lot
of energy in to pull those apart.

637
00:36:19,800 --> 00:36:22,560
How can we understand this?
We're going to go back to...

638
00:36:22,560 --> 00:36:24,000
If we have the periodic table
back up,

639
00:36:24,000 --> 00:36:28,040
we're going to go back to the top
element in this second row.

640
00:36:28,040 --> 00:36:29,560
This is lithium,

641
00:36:29,560 --> 00:36:32,320
and we're going to move round the
periodic table from lithium

642
00:36:32,320 --> 00:36:33,760
through beryllium, all the way -

643
00:36:33,760 --> 00:36:37,600
boron, carbon, nitrogen, oxygen,
fluorine, neon - and see
how the bonding changes.

644
00:36:37,600 --> 00:36:40,040
We have our elements lined up
and bringing down electrons

645
00:36:40,040 --> 00:36:42,000
so can we have the first two
lithiums, please?

646
00:36:42,000 --> 00:36:45,440
Could you come down to the front,
and you're bringing some electrons
with you.

647
00:36:45,440 --> 00:36:46,760
So these are our yellow electrons

648
00:36:46,760 --> 00:36:49,480
and could you put them
in the energy level here, please?

649
00:36:49,480 --> 00:36:51,040
That's it, put them in there,

650
00:36:51,040 --> 00:36:53,880
and if you return to your seats,
that's great. Thank you very much.

651
00:36:53,880 --> 00:36:57,200
What's happened here,
as the electrons have gone
into this region here,

652
00:36:57,200 --> 00:37:02,560
into these shelves here,
these have pulled the atoms together

653
00:37:02,560 --> 00:37:05,800
and this is because these
negatively charged electrons

654
00:37:05,800 --> 00:37:08,480
are helping pull the nuclei together

655
00:37:08,480 --> 00:37:11,080
when they're concentrated
in between the two atoms here.

656
00:37:11,080 --> 00:37:12,760
Can we have our next elements?

657
00:37:12,760 --> 00:37:14,600
We have beryllium -
could you come down?

658
00:37:14,600 --> 00:37:17,640
Now, on beryllium we see
on the screen here
the bonds are much stronger.

659
00:37:17,640 --> 00:37:20,880
Let's see why this is.
We add your electron here.

660
00:37:20,880 --> 00:37:23,280
That's it, these are moving
the atoms closer together,

661
00:37:23,280 --> 00:37:25,720
so even stronger still.

662
00:37:25,720 --> 00:37:29,240
So beryllium has two electrons,
creates a stronger bond now.

663
00:37:29,240 --> 00:37:33,240
Lithium, beryllium. The beryllium
atoms are held more tightly.

664
00:37:33,240 --> 00:37:37,240
OK, boron, on the screen here,
we have three electrons.

665
00:37:37,240 --> 00:37:41,440
Can you come down please, boron?
You've got one more electron here
than the beryllium had

666
00:37:41,440 --> 00:37:44,840
so you're going to add
your electrons. Could you add
your electrons in here?

667
00:37:44,840 --> 00:37:49,080
And again, these... Oh! That really
did move, that was pretty good.

668
00:37:49,080 --> 00:37:51,040
So you've a very strong bond
now for the boron -

669
00:37:51,040 --> 00:37:53,360
much stronger than the beryllium.
Very tightly held.

670
00:37:53,360 --> 00:37:56,600
We've got three electrons bonding
these boron atoms together.

671
00:37:56,600 --> 00:38:01,280
Can we have carbons now, please?
OK, and that last one.

672
00:38:01,280 --> 00:38:03,480
OK,
so the atoms move closer together.

673
00:38:03,480 --> 00:38:07,600
Thank you very much, carbons.
We've got some very strong bonds
indeed now.

674
00:38:07,600 --> 00:38:14,480
In fact carbon there requires most
of the energy of all of the elements
to try and rip them apart.

675
00:38:14,480 --> 00:38:16,960
If we were trying to remove the same
number of atoms apart,

676
00:38:16,960 --> 00:38:19,560
we need more energy
for carbon than any other.

677
00:38:19,560 --> 00:38:22,240
This makes carbon incredibly strong.

678
00:38:22,240 --> 00:38:26,080
I have a sample of carbon here
to show you and demonstrate this.

679
00:38:26,080 --> 00:38:30,360
This is a diamond, we can see this
here. This is a real diamond.

680
00:38:30,360 --> 00:38:32,640
Very, very strong
because of these strong bonds.

681
00:38:32,640 --> 00:38:36,640
I nearly dropped it there.
But it is also incredibly hard.

682
00:38:36,640 --> 00:38:41,520
So hard, in fact, that
I can actually cut this glass.

683
00:38:41,520 --> 00:38:45,960
The glass is incredibly hard, of
course, but diamond is even stronger

684
00:38:45,960 --> 00:38:49,400
because of the strong bonds
between the carbon atoms. So...

685
00:38:53,200 --> 00:38:57,800
It's definitely cut into the glass.
In fact, it looks like
it's pretty deep.

686
00:39:00,640 --> 00:39:06,320
There we are. It's cut down this
crack where it's been scored
with the glass there.

687
00:39:06,320 --> 00:39:10,920
So a diamond, incredibly strong,
because of all these
bonding electrons

688
00:39:10,920 --> 00:39:12,840
keeping the carbon atoms together.

689
00:39:12,840 --> 00:39:15,120
We've still got further to go
along our periodic table.

690
00:39:15,120 --> 00:39:17,280
We've gone to carbon,
we're going to keep on going.

691
00:39:17,280 --> 00:39:20,000
So nitrogens,
you have five electrons in total,

692
00:39:20,000 --> 00:39:24,160
so let's see where these have to go.
We've run out of room here.

693
00:39:24,160 --> 00:39:26,760
You're going to have to put
your electrons in these ones

694
00:39:26,760 --> 00:39:29,040
so this is a slightly different
thing going on here.

695
00:39:29,040 --> 00:39:31,680
Would you put your electrons
in here? That's great.

696
00:39:31,680 --> 00:39:36,160
And these, actually, now are
concentrated outside of the middle

697
00:39:36,160 --> 00:39:39,840
and these electrons are pulling
the atoms further apart again.

698
00:39:39,840 --> 00:39:43,240
In fact, these do not help
the bonding. These are called
anti-bonding levels.

699
00:39:43,240 --> 00:39:44,880
Thank you very much, nitrogens.

700
00:39:44,880 --> 00:39:48,240
OK, we have our next element -
this is oxygen.

701
00:39:48,240 --> 00:39:51,880
Let's see what happens as we keep
going, adding another electron.

702
00:39:51,880 --> 00:39:54,520
Oxygens, you have to put yours
in this level here,

703
00:39:54,520 --> 00:39:58,680
and again these are in these
anti-bonding levels,
pulling our atoms apart.

704
00:39:58,680 --> 00:40:01,720
So oxygen is a weaker bond
than nitrogen.

705
00:40:01,720 --> 00:40:04,200
Let's go to our next atom.
We've got two fluorines coming.

706
00:40:04,200 --> 00:40:07,040
Let's see what happens when you get
together. OK. Add them in.

707
00:40:07,040 --> 00:40:11,120
That's great. Again, a very weak
bond now. It's pulled further apart.

708
00:40:11,120 --> 00:40:14,360
Fluorine has one more electron,
weakens the bond here

709
00:40:14,360 --> 00:40:17,400
and the fluorines are really
weakly held together.

710
00:40:17,400 --> 00:40:19,480
This is the one of the reasons
that makes fluorine

711
00:40:19,480 --> 00:40:22,560
so incredibly reactive.
It's because of these weak bonds.

712
00:40:22,560 --> 00:40:25,640
Finally, we have
our last element, neon.

713
00:40:25,640 --> 00:40:27,960
So, neon has eight
outermost electrons,

714
00:40:27,960 --> 00:40:30,600
so it has one more
than the fluorines had.

715
00:40:30,600 --> 00:40:33,400
Let's see where these have to go
in the remaining level here.

716
00:40:33,400 --> 00:40:36,480
So if you add your electrons into
these last anti-bonding levels...

717
00:40:36,480 --> 00:40:38,800
And it pulls the atoms
completely apart.

718
00:40:38,800 --> 00:40:41,560
So, this means the atoms do not
bond to each other.

719
00:40:41,560 --> 00:40:44,800
Thank you very much indeed
for your help there. Thank you.

720
00:40:44,800 --> 00:40:47,240
APPLAUSE

721
00:40:49,360 --> 00:40:52,720
So, if we just see our periodic
table again. Just have you up.

722
00:40:52,720 --> 00:40:54,760
That's great. Thank you very much.

723
00:40:54,760 --> 00:40:56,880
We're looking at these ones
over here.

724
00:40:56,880 --> 00:40:59,000
We see carbon,
very, very strong bonds.

725
00:40:59,000 --> 00:41:02,040
Nitrogen, not as strong as carbon,
but still pretty strong.

726
00:41:02,040 --> 00:41:04,760
Fluorine, very weak bonds.
Neon not bonded at all.

727
00:41:04,760 --> 00:41:07,760
But oxygen, you're just
about the right strength.

728
00:41:07,760 --> 00:41:10,760
You're still reactive because the
bonds aren't too incredibly strong

729
00:41:10,760 --> 00:41:12,320
between the oxygen atoms.

730
00:41:12,320 --> 00:41:14,640
Makes you very,
very reactive indeed.

731
00:41:14,640 --> 00:41:17,720
Oxygen, you really are
the elixir of life.

732
00:41:17,720 --> 00:41:21,480
It's you that keeps us all alive.
I'm going to demonstrate this now.

733
00:41:21,480 --> 00:41:24,000
So, at ease, periodic table.
Thank you.

734
00:41:24,000 --> 00:41:26,120
So, I have some breakfast
cereal here.

735
00:41:26,120 --> 00:41:28,680
This is just normal breakfast
cereal.

736
00:41:28,680 --> 00:41:30,280
I'm just going to put some
in the bowl.

737
00:41:30,280 --> 00:41:34,240
This is just the sort of thing
that you would normally do.

738
00:41:34,240 --> 00:41:37,000
But now instead of adding my milk...
Oops.

739
00:41:37,000 --> 00:41:42,080
Instead of adding my milk,
I'm going to add some liquid oxygen.

740
00:41:42,080 --> 00:41:44,160
So this is not the sort of thing
you normally do.

741
00:41:44,160 --> 00:41:46,560
We've cooled the oxygen down.
So this is oxygen gas

742
00:41:46,560 --> 00:41:49,160
that's been cooled down.
It has this beautiful blue colour.

743
00:41:49,160 --> 00:41:51,960
I'm just going to pour
this onto our Rice Krispies.

744
00:41:55,080 --> 00:41:59,200
OK. Now, I'm also going
to add a light.

745
00:41:59,200 --> 00:42:01,680
Just put my goggles on.

746
00:42:01,680 --> 00:42:04,200
This is also something
you don't normally do.

747
00:42:13,760 --> 00:42:18,920
An incredible amount of energy
is released there.

748
00:42:18,920 --> 00:42:23,120
This is as the Rice Krispies,
the breakfast cereal here...

749
00:42:23,120 --> 00:42:28,400
As our breakfast cereal combines
with the oxygen from the air.

750
00:42:28,400 --> 00:42:31,320
And believe it or not,
this is actually what happens

751
00:42:31,320 --> 00:42:34,560
inside our bodies.
Not quite like this.

752
00:42:34,560 --> 00:42:37,760
We don't have flames
coming out of our ears.

753
00:42:37,760 --> 00:42:41,440
But nonetheless, it is the reaction
between our breakfast cereal

754
00:42:41,440 --> 00:42:44,320
and the oxygen that we're breathing
in that gives us

755
00:42:44,320 --> 00:42:46,640
the energy to stay alive.

756
00:42:46,640 --> 00:42:50,640
And we have Laura here
to demonstrate this.

757
00:42:50,640 --> 00:42:53,560
She's been specially trained
in breathing

758
00:42:53,560 --> 00:42:56,520
with this rather delicate
apparatus here.

759
00:42:56,520 --> 00:42:59,040
OK. Would you like to put this on?

760
00:42:59,040 --> 00:43:00,800
Now, what's happening here?

761
00:43:00,800 --> 00:43:03,760
Laura is breathing in.
So if you breathe in...

762
00:43:03,760 --> 00:43:06,080
Breathing in normal air
and it's coming in through here,

763
00:43:06,080 --> 00:43:09,200
bubbling through this solution.
In the flask here,

764
00:43:09,200 --> 00:43:11,480
we have something called
lime water.

765
00:43:11,480 --> 00:43:14,080
Then Laura's breathing out through
this one. So the out air

766
00:43:14,080 --> 00:43:15,320
is coming out through here.

767
00:43:15,320 --> 00:43:18,920
Now, lime water reacts
with carbon dioxide.

768
00:43:18,920 --> 00:43:21,680
There's very little
carbon dioxide in the air,

769
00:43:21,680 --> 00:43:24,440
so there's no change
taking place here.

770
00:43:24,440 --> 00:43:26,920
When lime water reacts
with carbon dioxide,

771
00:43:26,920 --> 00:43:30,840
it turns cloudy due to
the formation of calcium carbonate.

772
00:43:30,840 --> 00:43:33,800
No calcium carbonate forming here.
But in the out...

773
00:43:33,800 --> 00:43:36,840
Well, we can begin to see already...
Keep breathing. Very good.

774
00:43:36,840 --> 00:43:40,200
You're breathing beautifully there.
OK. In the out, we can begin

775
00:43:40,200 --> 00:43:44,560
to see that it is going cloudy.
And this is because inside Laura,

776
00:43:44,560 --> 00:43:47,600
it is the same reaction
we saw taking place there.

777
00:43:47,600 --> 00:43:51,040
The breakfast cereal Laura
had this morning is reacting

778
00:43:51,040 --> 00:43:53,880
with the oxygen she's breathing in.
It's releasing a lot of energy

779
00:43:53,880 --> 00:43:57,360
and that's keeping her alive, but
she's breathing out carbon dioxide

780
00:43:57,360 --> 00:44:00,560
that is formed during
this process as the oxygen reacts

781
00:44:00,560 --> 00:44:03,440
with the fuel to produce
carbon dioxide.

782
00:44:03,440 --> 00:44:05,960
Thank you very much.
Give Laura a round of applause.

783
00:44:05,960 --> 00:44:08,080
APPLAUSE

784
00:44:12,320 --> 00:44:17,680
So, oxygen is incredibly important
just to stay alive.

785
00:44:17,680 --> 00:44:23,040
But we've seen that there's
only 21% of oxygen in the air.

786
00:44:23,040 --> 00:44:27,280
So, wouldn't it be better if there
was much more oxygen in the air?

787
00:44:27,280 --> 00:44:29,640
Well, probably not.

788
00:44:29,640 --> 00:44:33,320
I'm going to demonstrate this now
with the help of my volunteer here,

789
00:44:33,320 --> 00:44:37,400
sausage man. OK. Now, sausage man
is made of the same sort of things

790
00:44:37,400 --> 00:44:40,240
that I'm made up of.
He's made up of meat, of course.

791
00:44:40,240 --> 00:44:43,440
And I'm just going... We've
connected him to a heating wire.

792
00:44:43,440 --> 00:44:46,520
I'm just going to turn up this
heating wire here. So, there we are.

793
00:44:46,520 --> 00:44:48,320
The heating wire is just...

794
00:44:48,320 --> 00:44:51,760
Just turn it on
a very low voltage there.

795
00:44:51,760 --> 00:44:53,440
It's just beginning to heat up.

796
00:44:53,440 --> 00:44:55,840
Now, it's not really causing
too much of a problem.

797
00:44:55,840 --> 00:45:00,080
But watch what happens if I increase
the amount of oxygen in the air.

798
00:45:00,080 --> 00:45:02,800
Again, we're going to use the
liquid oxygen to do this.

799
00:45:02,800 --> 00:45:08,000
It's just to provide a lot
of oxygen gas in the environment.

800
00:45:08,000 --> 00:45:11,080
So he's just with
the heating coil there.

801
00:45:11,080 --> 00:45:13,760
Is anything beginning to happen?

802
00:45:13,760 --> 00:45:17,600
His leg's smoking a bit
as the wire's heating.

803
00:45:17,600 --> 00:45:19,840
So this is like you're
on a different planet

804
00:45:19,840 --> 00:45:23,000
and there's a lot of oxygen
on the planet here.

805
00:45:23,000 --> 00:45:26,120
You accidentally lean
against a cooker...

806
00:45:26,120 --> 00:45:27,920
And look what's happening here.

807
00:45:29,160 --> 00:45:32,400
Poor sausage man is now in flames.

808
00:45:35,280 --> 00:45:40,520
He's gone up rather
drastically here.

809
00:45:40,520 --> 00:45:45,000
This is because of the increased
oxygen in his environment.

810
00:45:45,000 --> 00:45:47,440
So, yes, of course,
we do need oxygen to stay alive.

811
00:45:47,440 --> 00:45:49,400
It does provide us with our energy.

812
00:45:49,400 --> 00:45:54,040
But too much would
definitely be a bad thing.

813
00:45:54,040 --> 00:45:57,080
I need to put out our sausage man.
I think it might be very difficult

814
00:45:57,080 --> 00:46:00,280
to put him out since there's
so much oxygen in there.

815
00:46:00,280 --> 00:46:03,600
Let's try... We've got
some tomato ketchup here.

816
00:46:03,600 --> 00:46:05,920
LAUGHTER

817
00:46:05,920 --> 00:46:06,960
It's...

818
00:46:09,400 --> 00:46:10,400
Wow.

819
00:46:14,280 --> 00:46:18,920
It leaks as well. Great. Somebody
didn't put the top on properly.

820
00:46:18,920 --> 00:46:20,360
There we are. We've put him out.

821
00:46:23,400 --> 00:46:26,440
Oops. What a mess. OK.

822
00:46:26,440 --> 00:46:28,480
OK. So, you get the idea

823
00:46:28,480 --> 00:46:32,840
that too much oxygen would
certainly be bad for us.

824
00:46:32,840 --> 00:46:36,800
But on a serious note, it's
incredibly difficult to put out

825
00:46:36,800 --> 00:46:38,240
a forest fire.

826
00:46:38,240 --> 00:46:41,480
These are incredibly difficult to
put out, even with just 21% oxygen.

827
00:46:41,480 --> 00:46:45,440
If it was 100% oxygen,
there would be no chance.

828
00:46:45,440 --> 00:46:48,800
So 21% of the air
is made up of oxygen.

829
00:46:48,800 --> 00:46:50,760
This is how much we need to breathe.

830
00:46:50,760 --> 00:46:54,680
But what happens if you reduce
the amount? Can we still stay alive?

831
00:46:54,680 --> 00:46:57,560
Well, I went to a place
just outside Cambridge

832
00:46:57,560 --> 00:47:00,240
where they've reduced the amount
of oxygen in their rooms there

833
00:47:00,240 --> 00:47:03,040
from 21% down to 15%.

834
00:47:03,040 --> 00:47:06,480
And they say that things just
can't burn in this environment.

835
00:47:06,480 --> 00:47:09,120
Well, let's see what happened.
Can I have a fire? Yes.

836
00:47:09,120 --> 00:47:11,760
Can I set fire to your newspaper?
I've got a newspaper here

837
00:47:11,760 --> 00:47:15,680
and you try to light my newspaper.
OK. All right.

838
00:47:16,800 --> 00:47:21,480
See if it works. Shall I use
a lighter? Use the lighter.

839
00:47:21,480 --> 00:47:24,320
I'll try the lighter first of all.
OK.

840
00:47:27,680 --> 00:47:30,520
Oh. Empty? I don't think
it's a very good one.

841
00:47:30,520 --> 00:47:34,720
Try mine if yours is empty.
This is a new one, is it?

842
00:47:34,720 --> 00:47:39,120
OK. OK. Doesn't work. Matches.
Matches. OK.

843
00:47:39,120 --> 00:47:40,760
Ah! This is better.

844
00:47:40,760 --> 00:47:42,120
OK. Try again.

845
00:47:43,840 --> 00:47:45,880
Of course, the matches
are still lighting

846
00:47:45,880 --> 00:47:48,520
because they have their own oxygen
built in here.

847
00:47:48,520 --> 00:47:51,560
That's what's allowing them
to strike,

848
00:47:51,560 --> 00:47:54,800
but there's not enough oxygen
to allow your newspaper

849
00:47:54,800 --> 00:47:57,040
or the match to actually burn.

850
00:47:57,040 --> 00:48:01,400
It's only the match head with
oxygen there. Absolutely correct.

851
00:48:01,400 --> 00:48:04,360
The newspaper could not burn
by itself. Impossible.

852
00:48:04,360 --> 00:48:07,040
Of course, we can breathe fine
in here. It doesn't affect us.

853
00:48:07,040 --> 00:48:10,040
It doesn't affect us at all.
We could live in here for ever.

854
00:48:10,040 --> 00:48:11,320
Very impressive.

855
00:48:15,760 --> 00:48:20,400
We've come outside to try a slightly
larger-scale version of the lighter.

856
00:48:20,400 --> 00:48:25,320
The lighter couldn't start a fire
in the room because it didn't bring

857
00:48:25,320 --> 00:48:28,920
any oxygen with it and there wasn't
enough oxygen in the room itself.

858
00:48:28,920 --> 00:48:30,840
So this should... This is petrol.

859
00:48:30,840 --> 00:48:33,400
I've soaked this torch
here in petrol.

860
00:48:33,400 --> 00:48:35,640
It should light nice and easily.

861
00:48:35,640 --> 00:48:40,320
Yes. Look at that.
So, this is burning rather well.

862
00:48:40,320 --> 00:48:43,160
The question is,
will this go out in the room?

863
00:48:44,560 --> 00:48:45,720
Well, let's find out.

864
00:48:59,000 --> 00:49:02,240
And the fire has instantly gone out.

865
00:49:02,240 --> 00:49:07,320
There really just isn't enough
oxygen in this room to allow this,

866
00:49:07,320 --> 00:49:09,920
my torch here, to carry on burning.

867
00:49:09,920 --> 00:49:12,920
But there is enough for me
to carry on living.

868
00:49:12,920 --> 00:49:14,960
So that's pretty good and I'm happy.

869
00:49:17,320 --> 00:49:21,480
So, this fire prevention system
works by decreasing

870
00:49:21,480 --> 00:49:25,360
the amount of oxygen and increasing
the amount of nitrogen.

871
00:49:25,360 --> 00:49:28,280
Nitrogen is a very important
component of the air

872
00:49:28,280 --> 00:49:32,320
because it's so inert,
because of these very strong bonds.

873
00:49:32,320 --> 00:49:34,720
So we're now going to look
at some of the properties

874
00:49:34,720 --> 00:49:37,600
of this inert gas, nitrogen.

875
00:49:37,600 --> 00:49:41,320
And this is one of the components
in many explosives

876
00:49:41,320 --> 00:49:43,480
such as this nitroglycerin here.

877
00:49:43,480 --> 00:49:46,400
This is a very dangerous explosive.

878
00:49:46,400 --> 00:49:50,200
In fact, Alfred Nobel...

879
00:49:50,200 --> 00:49:57,160
earned his money in trying to work
out how to make this more stable.

880
00:49:57,160 --> 00:50:00,320
I need to put on some special kit
here, some protective clothing

881
00:50:00,320 --> 00:50:03,520
and some ear protectors. OK.

882
00:50:04,800 --> 00:50:09,280
And I'm going to add a drop of
nitroglycerin to the filter paper.

883
00:50:13,760 --> 00:50:17,080
Now then. Adding a drop
of nitroglycerin.

884
00:50:17,080 --> 00:50:19,080
There we are. That's it.

885
00:50:23,040 --> 00:50:28,800
And I think I'll just remove
this nitroglycerin from here.

886
00:50:28,800 --> 00:50:31,080
I don't want to be too close
when this goes off.

887
00:50:32,160 --> 00:50:35,840
So I'll hand this to Mark.
Thank you. Right.

888
00:50:35,840 --> 00:50:39,480
Now, the nitroglycerin contains
a lot of nitrogen locked up

889
00:50:39,480 --> 00:50:42,800
into its chemical composition.

890
00:50:42,800 --> 00:50:47,760
And it's the sudden release of this
that gives it its explosive power.

891
00:50:49,200 --> 00:50:51,800
BANG!

892
00:51:05,120 --> 00:51:06,960
That really was quite violent,

893
00:51:06,960 --> 00:51:10,120
the sudden release
of that nitrogen gas.

894
00:51:10,120 --> 00:51:13,680
And that's what makes
an explosive explosive.

895
00:51:13,680 --> 00:51:16,200
Most of them contain
nitrogen built in.

896
00:51:16,200 --> 00:51:19,800
But remarkably, this reaction, this
explosive release of nitrogen gas,

897
00:51:19,800 --> 00:51:24,000
has been used to save
thousands of lives.

898
00:51:24,000 --> 00:51:25,960
For this, I need a car.

899
00:51:25,960 --> 00:51:29,120
Have you got a car there,
please, Chris?

900
00:51:29,120 --> 00:51:32,760
OK. Well, it's not exactly
a real car.

901
00:51:32,760 --> 00:51:36,000
But it is a real steering wheel. OK.

902
00:51:36,000 --> 00:51:39,480
So, this contains a compound
with nitrogen in it.

903
00:51:39,480 --> 00:51:41,320
It's nitrogen combined with sodium.

904
00:51:41,320 --> 00:51:43,720
Can we have our periodic table
up for a second, please?

905
00:51:43,720 --> 00:51:48,360
So, we have nitrogen over here
combined with sodium over here.

906
00:51:48,360 --> 00:51:51,440
But it's the formation
of our very, very strong

907
00:51:51,440 --> 00:51:56,120
nitrogen-nitrogen bonds that leads
to the rapid inflation

908
00:51:56,120 --> 00:51:57,360
of this air bag.

909
00:51:57,360 --> 00:52:00,800
Now, I need a volunteer
from the audience for this, please.

910
00:52:00,800 --> 00:52:03,880
Er, who shall we have? Yes, would
you like to come down the front?

911
00:52:03,880 --> 00:52:06,680
Thank you very much. Would you
like to stand all the way over here?

912
00:52:06,680 --> 00:52:09,120
And your name is...?
Fred. Fred. OK, Fred.

913
00:52:09,120 --> 00:52:11,160
Now, you are going
to trigger this air bag.

914
00:52:11,160 --> 00:52:14,400
So if I just take this from Chris.
Is this primed?

915
00:52:14,400 --> 00:52:16,840
Just going to make sure
it's all OK to trigger.

916
00:52:20,920 --> 00:52:23,720
OK. Thank you very much.
Now, if you stand over here.

917
00:52:23,720 --> 00:52:26,720
He's very keen to get
a hand on the trigger here.

918
00:52:26,720 --> 00:52:29,240
Now, we're going to count down
from three. OK. If you hold this.

919
00:52:29,240 --> 00:52:32,000
Don't press the button yet. OK.
Now, when we've counted down,

920
00:52:32,000 --> 00:52:33,440
I want you to press the button.

921
00:52:33,440 --> 00:52:36,120
But don't blink.
If you blink, you'll miss this.

922
00:52:36,120 --> 00:52:40,400
It's a very quick reaction. OK.
So, three, two, one.

923
00:52:40,400 --> 00:52:43,560
BANG!
There we are.

924
00:52:43,560 --> 00:52:46,080
OK. Thank you very much indeed.
A round of applause for Fred.

925
00:52:46,080 --> 00:52:48,680
APPLAUSE

926
00:52:48,680 --> 00:52:52,080
So, this air bag works here

927
00:52:52,080 --> 00:52:56,240
because the nitrogen really wants
to bond to itself to form

928
00:52:56,240 --> 00:53:00,640
these nitrogen molecules and it's
this explosive release of nitrogen

929
00:53:00,640 --> 00:53:04,760
that inflates the air bag so
quickly. We can see this here

930
00:53:04,760 --> 00:53:09,440
in slow motion. Actually, when
the crash test dummy hits the bag,

931
00:53:09,440 --> 00:53:13,240
this bag is actually deflating.
The air is coming out of this.

932
00:53:13,240 --> 00:53:16,640
But it needs to be released
so quickly,

933
00:53:16,640 --> 00:53:19,400
that's why an explosive is needed.

934
00:53:19,400 --> 00:53:21,640
So nitrogen here saving lives.

935
00:53:21,640 --> 00:53:24,640
But actually, nitrogen
is vital for life.

936
00:53:24,640 --> 00:53:26,480
We couldn't live without it.

937
00:53:26,480 --> 00:53:31,600
Every protein in every cell in our
body is made up of amino acids.

938
00:53:31,600 --> 00:53:35,040
And every one of these amino acids
contains nitrogen.

939
00:53:35,040 --> 00:53:37,680
So somehow we need to take
the nitrogen from the air

940
00:53:37,680 --> 00:53:40,720
and get it to combine with other
elements so we can form compounds

941
00:53:40,720 --> 00:53:42,040
that are useful to us.

942
00:53:42,040 --> 00:53:45,200
Now, plants have learnt how to do
this over millions of years,

943
00:53:45,200 --> 00:53:47,880
but it took chemists
a long time to do this.

944
00:53:47,880 --> 00:53:51,960
And the first way this was achieved
was by emulating nature...

945
00:53:51,960 --> 00:53:53,960
THUNDER
..a process in nature

946
00:53:53,960 --> 00:53:57,320
where nitrogen and oxygen
are beginning to react.

947
00:53:57,320 --> 00:53:59,040
During this electrical storm,

948
00:53:59,040 --> 00:54:02,840
the lightning here is providing
sufficient energy to split apart

949
00:54:02,840 --> 00:54:06,920
these molecules and this can allow
nitrogen and oxygen to recombine.

950
00:54:06,920 --> 00:54:11,120
We're going to try and do this
in the lecture now. And I have...

951
00:54:11,120 --> 00:54:13,840
Well, this is what every
mad scientist should have.

952
00:54:13,840 --> 00:54:17,120
It's a Jacob's ladder
and here we see it switched on.

953
00:54:17,120 --> 00:54:19,920
So what we're doing here
is passing thousands of volts

954
00:54:19,920 --> 00:54:24,640
between these two electrodes
and this is causing the molecules

955
00:54:24,640 --> 00:54:28,040
in the air to be ripped apart,
ripping their electrons out.

956
00:54:28,040 --> 00:54:30,080
This heats up the air just above it,

957
00:54:30,080 --> 00:54:33,040
making it easier to pass the
electric current through that,

958
00:54:33,040 --> 00:54:35,720
which is why this thing
is gradually rising.

959
00:54:35,720 --> 00:54:40,480
But how will we know if there is any
chemical reaction taking place here?

960
00:54:40,480 --> 00:54:43,080
Well, we're going to keep
an eye on this

961
00:54:43,080 --> 00:54:46,360
and look for signs of a reaction.
We should see a colour change.

962
00:54:46,360 --> 00:54:49,360
Now, I can demonstrate the colour
change that we're going to see.

963
00:54:49,360 --> 00:54:51,360
I have two flasks here.

964
00:54:51,360 --> 00:54:54,440
This contains a compound
called nitric oxide.

965
00:54:54,440 --> 00:54:56,480
This is just air.

966
00:54:56,480 --> 00:54:59,120
But when the two come together...

967
00:55:00,240 --> 00:55:01,200
..we form...

968
00:55:03,880 --> 00:55:08,560
..a new compound that we can see,
that isn't colourless.

969
00:55:08,560 --> 00:55:12,960
There we are. And this is the gas
nitrogen dioxide.

970
00:55:12,960 --> 00:55:17,440
So, this is what we're looking
for in our Jacob's ladder.

971
00:55:17,440 --> 00:55:20,120
So the nitrogen,
if it combines with the oxygen,

972
00:55:20,120 --> 00:55:25,200
we may be able to see this
coloured gas nitrogen dioxide.

973
00:55:25,200 --> 00:55:29,400
We'll keep an eye on the tube
there. It just contains air.

974
00:55:29,400 --> 00:55:32,280
I'll just get rid of that.

975
00:55:32,280 --> 00:55:36,640
But this isn't really
real lightning.

976
00:55:36,640 --> 00:55:38,880
This is only a very small spark
here.

977
00:55:38,880 --> 00:55:42,240
We can maybe begin to see
hints of some colour change,

978
00:55:42,240 --> 00:55:45,000
but we'll keep an eye on it.
We need a bigger spark.

979
00:55:45,000 --> 00:55:48,680
We need something to produce
about a million volts.

980
00:55:48,680 --> 00:55:51,320
And this is what this is for.

981
00:55:51,320 --> 00:55:53,280
This is a Tesla coil

982
00:55:53,280 --> 00:55:57,040
and it can generate
a million volts.

983
00:55:57,040 --> 00:55:59,480
We've had some problems
with this bit of kit.

984
00:55:59,480 --> 00:56:03,320
It basically fries all the cameras,
all the electrics, all the lights.

985
00:56:03,320 --> 00:56:08,400
So this really should give us
some rather impressive lightning.

986
00:56:08,400 --> 00:56:11,760
Now, I must ask everyone just
to remain in your seats

987
00:56:11,760 --> 00:56:14,480
for this demonstration.
Let's see how we go.

988
00:56:19,560 --> 00:56:21,600
BUZZING

989
00:56:49,400 --> 00:56:52,080
Phew.

990
00:56:52,080 --> 00:56:54,520
CHEERING AND APPLAUSE

991
00:56:59,720 --> 00:57:03,640
That really... That really is quite
nerve-racking, I must say.

992
00:57:03,640 --> 00:57:06,320
And what we are seeing here
with all that energy

993
00:57:06,320 --> 00:57:09,080
was causing the nitrogen molecules
and the oxygen molecules

994
00:57:09,080 --> 00:57:11,560
to be ripped apart
and then they recombine

995
00:57:11,560 --> 00:57:14,800
to form nitrogen dioxide
and that's what we can see,

996
00:57:14,800 --> 00:57:17,840
this brown colour here now
in our Jacob's ladder.

997
00:57:17,840 --> 00:57:20,240
And we can also
form molecules of ozone.

998
00:57:20,240 --> 00:57:23,960
That's three oxygen atoms together.
So, what have we learnt here?

999
00:57:23,960 --> 00:57:27,800
We've learnt that the air is more
complicated than we ever thought.

1000
00:57:27,800 --> 00:57:30,760
The alchemists thought it was
made up of just one element

1001
00:57:30,760 --> 00:57:34,440
but they were wrong. It's made up
of a number of different elements,

1002
00:57:34,440 --> 00:57:38,600
of nitrogen, oxygen. We've seen
how important they are to our lives.

1003
00:57:38,600 --> 00:57:40,720
Without the oxygen,
we'd all be dead.

1004
00:57:40,720 --> 00:57:43,040
But with too much,
we couldn't survive either.

1005
00:57:43,040 --> 00:57:46,880
We've also seen how the very rare
gases, the noble gases, can be used

1006
00:57:46,880 --> 00:57:49,360
to save lives in hospitals.

1007
00:57:49,360 --> 00:57:53,800
Now, the alchemists spent their
lives trying to master the elements.

1008
00:57:53,800 --> 00:57:56,280
But they only scratched the surface.

1009
00:57:56,280 --> 00:57:58,360
They might have been able
to play with fire,

1010
00:57:58,360 --> 00:58:01,560
but they couldn't control it
or understand what it was made of.

1011
00:58:01,560 --> 00:58:04,920
Nor could they pick out the elements
from the air and use them

1012
00:58:04,920 --> 00:58:06,920
to make the world a better place.

1013
00:58:06,920 --> 00:58:10,720
This is where the modern alchemist
takes over.

1014
00:58:10,720 --> 00:58:13,920
Join us in the next lecture
where we'll investigate

1015
00:58:13,920 --> 00:58:16,560
how a glass of water contains
the remnants

1016
00:58:16,560 --> 00:58:19,200
of the most violent reactions
in the world.

1017
00:58:19,200 --> 00:58:20,400
Good night. Thank you.

1018
00:58:24,160 --> 00:58:27,120
Subtitles by Red Bee Media Ltd