Copper

This week's element is copper, whose symbol, Cu, comes from the Latin cuprum for the island of Cyprus because it was a major exporter of copper. Copper's atomic number is 29. Copper is a soft metal that has a high thermal and electrical conductivity. If you've been paying attention, you will also realise this shiny orange-red metal is the first one I've introduced to you that is not a shiny pale grey in its native state. In fact, there are only three metals that have a colour other than grey when in their pure, native state, and copper is the first of them.

Copper has always been important to people, even in ancient times: Ötzi the iceman, who was murdered sometime around 3200 BC and discovered in the Alps, was in possession of an axe head that was almost pure copper. But copper use dates back much further than that: for example, a copper pendant was found in northern Iraq that dates to 8700 BC.

Copper is most familiar to us because it was used in coins. Today, copper is still used in coins, but it is primarily used by industry, in electrical wires, roofing and plumbing materials, and in industrial machinery. Copper is rare because it is 100% recyclable without losing any of its quality – a feature that makes construction sites and cell phone towers a popular target of thieves in these difficult economic times. It is estimated that 80% of the copper that was ever mined is still in use today – which sometimes makes me ponder about the history of the individual copper atoms in that make up the coins in my pocket.

Here's a new video about copper, including a nice demonstration and some stories from The Professor.

As the professor mentioned, copper is important to living things, too. I can still remember the day when I was a graduate student, observing (and then later carrying out) surgery on moths, and noticing that they have the loveliest pale blue blood. As I learned, instead of hæmoglobin, their blood (hæmolymph) uses the protein, hæmocyanin, which relies on copper ions instead of iron ions to reversibly bind oxygen and carry it to their tissues. It is the copper that gives their blood its beautiful pale blue colour (before it oxidizes to black, that is). In fact, most invertebrates, including mollusks and some arthropods, use hæmocyanin as their oxygen carrier.

Although toxic at high concentrations, copper is an important trace element for plants and animals, but not always for other forms of life. At low concentrations, copper(II) ions inhibit the growth of some microbes and fungi, which makes it one of the central ingredients in wood preservatives and in fungicides.

Video journalist Brady Haran is the man with the camera and the University of Nottingham is the place with the scientists. You can follow Brady on twitter @periodicvideos and the University of Nottingham on twitter @UniNottingham

You've already met these elements:

Nickel: Ni, atomic number 28
Cobalt: Co, atomic number 27
Iron: Fe, atomic number 26
Manganese: Mn, atomic number 25
Chromium: Cr, atomic number 24
Vanadium: V, atomic number 23
Titanium: Ti, atomic number 22
Scandium: Sc, atomic number 21
Calcium: Ca, atomic number 20
Potassium: K, atomic number 19
Argon: Ar, atomic number 18
Chlorine: Cl, atomic number 17
Sulfur: S, atomic number 16
Phosphorus: P, atomic number 15
Silicon: Si, atomic number 14
Aluminium: Al, atomic number 13
Magnesium: Mg, atomic number 12
Sodium: Na, atomic number 11
Neon: Ne, atomic number 10
Fluorine: F, atomic number 9
Oxygen: O, atomic number 8
Nitrogen: N, atomic number 7
Carbon: C, atomic number 6
Boron: B, atomic number 5
Beryllium: Be, atomic number 4
Lithium: Li, atomic number 3
Helium: He, atomic number 2
Hydrogen: H, atomic number 1

Here's a wonderful interactive Periodic Table of the Elements that is just really really fun to play with!

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