So this is a very, very, very nice sample
of very fine copper wire. So the copper wire here is…what width
is this? This is 0.0. I’m not even going to… that is just
too small. Copper is unusual among the metals in that
it is coloured. It is only copper and gold that are coloured.
So you can see here we have copper coins. In fact, you can
see that this one looks brighter that that one, that is a modern
one that’s been plated and you can see it is a slight cheat
because modern UK coins although they have copper inside they
have iron inside so with a magnet you can just pick them up
but the proper copper coins are not magnetic at all. So it is 0.1 of a millimetre. So the copper
wire here is very, very high grade, this is grade 1 copper wire
and it is 0.1 of a millimetre in diameter and you can see the
wonderful copperous lustre. Copper compounds are not very reactive, in
fact if you put iron filings into copper sulphate or some
other copper salt, the copper coats out on the iron filings and
which are gray and then they go a nice sort of rosy colour
almost like gold. It’s often one of the first experiments
that people do as chemists. What do you mean by ‘Grade 1 copper’? So this very high purity, this is like 99.99%
copper, used for electronics fabrications and high quality
research samples. It is a very beautiful sample. On the other hand, quite surprisingly, that
copper chloride is quite reactive. I did an experiment once in
which I took a cupcake container which was made of aluminium
and put copper chloride in it, the solution, and it
boiled. I was trying to demonstrate how reactive it was to my children.
I didn’t notice that the copper chloride had burnt
through the aluminium and made a hole in our sitting room
carpet. Most organisms, you and me, use iron in our
blood to transport oxygen, that’s what makes our
blood red, but in some sorts of crustaceans crabs and lobsters
they are different: they use copper. They use a copper
called hemocyanin. It is a blue compound of copper.
Cyan is some classical word for blue, so they really had
blue blood. And these hemocyanin uses two atoms of copper
in each molecule to transport the oxygen around the body of
the crab or lobster but it is not nearly as good as haemoglobin.
So if you start running after a crab or lobster, it
quickly gets tired compared to running after a rabbit or something
like that which can keep going faster than you can.