We've decided to make a new video
about aluminium
because it's a long time
over five years
since we made the first one
and... we didn't say very much.
Aluminium
is a surprisingly abundand element.
If you look at this periodic table here,
where the area of the different elements
gives you a rough idea of the abundance
you can see that aluminium
is one of the most abundant metals
up there with sodium, magnesium and calcium.
More aluminum than potassium;
about the same or perhaps even more than iron.
We're never going to run out of aluminium.
The problem with aluminium is that
you don't find aluminium metal in nature
as a metal.
It's always tied up with other compounds;
mostly with oxygen,
in clays.
You know what clays are,
the sort of muddy stuff
that you get stuck on your shoes
when it's raining.
To get the aluminium out of the clay,
that is, to break the aluminium/oxygen bonds,
which are very strong;
requires a lot of energy,
which comes from electricity.
So, making aluminium
is very energy intensive.
That's why
people like to recycle aluminium
because once you've got it, it's worth preserving;
but it's fantastically important
because aluminium is a very light metal.
And it's often used as an alloy
because the aluminium alloys
are stronger than the aluminium itself,
so, if you're using it for aircraft
or some other use like that
where you want to combine lightness
with strength
then the stronger you can make it, the better.
But when it was first made,
in the 19th century,
isolated as a metal
it was terrifically valuable
and there are stories of the French Emperor
serving his honored guests
with aluminium plates
or aluminium cutlery
while the less important people had silver or gold;
but those times have passed
and now
you can get cupcakes and things like that
surrounded by
foil of aluminium.
Aluminium is a very good metal
for making things
because it has a very thin coating
of aluminium oxide on the surface
which prevents it [from] reacting with things.
But as soon as that coating goes
it becomes very reactive.
Alfred Worden: Hadley Base, do you read Houston?
David Scott: Yeah. Now, 5 by, Joe.
Worden: Okay.
Worden: And I guess we're standing by for your
high-gain alignment per the checklist.
Scott: Okay, stand by.
You may have seen our video
where we put copper chloride in one of these
cupcake holders...
[First of all
I'm going to dissolve some up
and make a fairly concentrated solution.
I'm going to place this here.]
...and what came out
was this,
or rather the copper chloride
came out through the hole.
[It starts
boiling really quite nicely.
Now, imagine
I was doing this for my children
who were quite small at that time,
and...
VOOSH!]
And the aluminium was completely dissolved up
forming aluminium chloride
and copper metal.
In my own research,
aluminium is quite important;
quite a lot of our equipment uses aluminium.
Not so much for the
high pressure tubing that we use
because quite a lot of my reaserch involves high pressures
but we use it for the metal blocks
that we put round the tubing
so that we can heat it up.
Aluminium has a good
electrical conductivity,
and it's also easy to machine.
This is a piece of equipment here
where we have a tube going down the middle.
You can see the diameter of the tube here.
Around it
is an aluminium block
and an electrical heater.
Now, this particular case
there was an accident,
or a mishap,
because
the thermocouple
that was controlling the temperature of this
fell out.
So, the heater got hotter
and hotter,
and eventually,
the aluminium melted
and poured down here.
And I think this is really beautiful.
Well,
fortunately, I was not in the lab
or I would've got very angry with my students
but
I think when it happened
it was quite exciting;
this would have been glowing almost red
because the melting point of aluminium is around
500 degrees centigrade.
But then once it formed
originally it was very shiny
but quickly, it again developed
the surface layer of aluminium oxide.
If you have fine particles of Aluminium
and blow them into a flame...
...then they will burn quite spectacularly
and you form aluminium oxide.
Now, on the face of it, aluminium oxide
sounds a rather boring compound
but it's really very useful
and we use it quite a lot in our research
in all sorts of different ways.
It looks like a white powder.
Not very exciting.
But in our group
this aluminium oxide has been a fantastic catalyst
All sorts of reactions
that we didn't expect
have gone with this material.
My students keep it in a bottle
almost like a magic catalyst
and I've only been given a little to show you.
It acts as a solid acid
which can be used at very high temperature
and will get various acid-catalyzed reactions
of organic compounds.
It will make ethers,
we have made various alkynes
and a whole series of different compounds
and my students still use it very much.
If you melt the aluminium oxide,
which we can't do here but can be done industrially,
you can make single crystals
which are transparent like glass
and then you can grow a single crystal tube,
like this one,
which because it's a single crystal,
it's terrifically strong.
It's the defects that make something weak
and so if you have just one crystal
there are no defects
and so it's very strong.
So you can put a very high pressure inside this tube
without it blowing up.
Brady: But you could make that tube out of metal, professor.
Professor: But, if you have a metal
then you can't see what's going on inside,
and we're using these tubes
for photochemical reactions.
So, we take a light like this,
and shine it on the chemicals going through the tube
under high pressure
and we can convert one chemical into another.
We can do this very efficiently
because the light is absorbed by
the molecules that we want to react
and so we dont waste the energy on everything else.
And using LEDs, which are a very efficient light source,
you can get a process that is very energy efficient
and it all depends on having this sapphire tube.
This is synthetic sapphire.
The real sapphire, the gems,
have impurities in them, of other metals,
which give them the nice colors,
particularly the blue.
Princess Kate has a blue sapphire ring
which belonged to her husband's mother, Princess Di,
before her.
And so, these are very valuable ones.
But synthetic sapphire is also expensive
but not in the same class as a natural gem.
Brady: What can nature do that the guys at the sapphire factory
can't do?
Professor: Nature has time.
The people who grow this
will take hours or days or perhaps weeks to grow it.
Nature can spend
thousands or millions of years growing a particular gem
and therefore they can heat it up and cool it down
in natural surroundings, in volcanoes... or whatever
far more slowly
than people can afford to do industrially.
There's a lot of argument
whether you should call it
aluminum or aluminium
Now, there isn't a totally correct one because
both forms are acceptable.
But, all or nearly all
chemists use aluminium
because it's very important to use a
standardized nomenclature right across the world.
And I think aluminium sounds nicer.
Student: Hi professor, my question is
is it aluminum or aluminium?
'Cause I want to know what to call my aluminium model.
Apparantly, there was a decision in 1990
by IUPAC
the International Union of Pure and Applied Chemistry
that it should definately be called
A L U M I N I U M
but then they relented three years later
and said you could use aluminum as well.
But if you're a serious chemist
you really need to say aluminium, because otherwise
people won't find your papers, your publications,
when they search because they'll almost certainly put an "i"' in the name.
Aluminium is frequently used
or used [to be] frequently used
kkfor sauce pans, for cooking in
because it's easy to make, easy to machine
and particularly when people used electric stoves
it was easy to make a flat bottom
so that you got good contact between the
electric element and the sauce pan.
The problem with aluminium sauce pans
is that if you're cooking some fairly acidic food,
for example boiling lemons or rhubarb
something like that which is quite acidic
you can dissolve some of the aluminium
and people got quite worried about
getting aluminium in their food.
Also, if you cook red cabbage,
which is an indicator;
blue for alkali, red for acid,
then if you boil it in an aluminium sauce pan
it goes blue.
And earlier in my carreer
I used a red cabbage together with a white one
to make a Union Jack, a U.K. flag
with a mixture of red and blue-red cabbage
and the white from the white cabbage.
Unfortionately, I've lost the photo; Brady is very cross with me.
But it was quite fun cooking it in the kitchen.
I did it once myself, but it was such a lot of work
that the second time a got one of my students to do it.