Elements in the Human Body

The most common elements in the human body (logarithmic scale, data from Wikipedia, chart produced using R). Yes, we are mostly made of air!


Starting an element collection

In the spirit of the wonderful photobook The Elements by Theodore Gray (which I have previously blogged about), starting a collection of elements is a great way of introducing yourself (or your children) to basic chemistry. Here are some suggestions, and a list of 24 elements to start with….

2: Helium (He)

Helium is lighter than air, so balloons are often filled with helium.

6: Carbon (C)

Carbon is most easily added to your collection in the form of charcoal. Zinc–carbon batteries have a carbon rod at the centre.

7: Nitrogen (N)

Air is about 78% nitrogen. To add nitrogen to your collection, just fill a small bottle with air.

8: Oxygen (O)

Air is about 21% oxygen. To add oxygen to your collection, just fill a small bottle with air.

9: Fluorine (F)

Fluorine is a toxic gas. But octahedral fluorite crystals (calcium fluoride, CaF2) make a great addition to a collection.

11: Sodium (Na)

Sodium is a reactive metal which will spontaneously catch fire when in contact with water. But sodium chloride (ordinary table salt, NaCl) is perfectly safe.

12: Magnesium (Mg)

Magnesium is a flammable metal, but you can substitute crystals of Epsom salts (magnesium sulfate, MgSO4), which can be obtained from a pharmacy.

13: Aluminium (Al)

Aluminium (aluminum in the USA) is most easily available as aluminium foil.

14: Silicon (Si)

Silicon is widely used in transistors and integrated circuits (chips).

15: Phosphorus (P)

The side of a box of matches is largely composed of phosphorus.

16: Sulfur (S)

Sulfur powder, also called “flowers of sulfur,” is available from pharmacies.

17: Chlorine (Cl)

Chlorine is a toxic yellowish-green gas. But sodium chloride (ordinary table salt, NaCl) is perfectly safe.

20: Calcium (Ca)

Calcium is a reactive metal, but you can substitute crystals of calcite (calcium carbonate, CaCO3) or gypsum (calcium sulfate, CaSO4).

24: Chromium (Cr)

Chromium is used for plating (“chrome plating”) to prevent rusting. Also, “stainless steel” is between about 16% and 25% chromium.

26: Iron (Fe)

Iron is one of the most widely used metals. Iron nails are easy to add to your collection. Like nickel and cobalt, iron is attracted by a magnet.

28: Nickel (Ni)

The United States “nickel” coin is actually only 25% nickel (and 75% copper), but objects made of pure nickel can be found. Indeed, Canadian “nickel” coins from 1955–1981 are almost pure nickel.

29: Copper (Cu)

Copper pipes are widely used in plumbing. You can buy copper plumbing fittings, or get offcuts of pipe from a plumber. Copper electrical wire is also easy to find.

30: Zinc (Zn)

Galvanised iron is coated with zinc to prevent rusting. Also, filing off the copper coating on a US penny reveals a coin made mostly of zinc.

47: Silver (Ag)

A silver coin, or a piece of silver jewellery, would make a fine addition to your collection.

53: Iodine (I)

Iodine is a dark solid, but is sold in pharmacies as a brown solution in alcohol, called “tincture of iodine.”

60: Neodymium (Nd)

Neodymium is one of the “rare earth” elements. Neodymium magnets are the most common form of strong magnet. They are made of an alloy of neodymium, iron and boron (Nd2Fe14B).

74: Tungsten (W )

The filament in an incandescent light bulb is made from tungsten (but because of the danger of broken glass, only an adult should attempt to remove the filament, and then only with very great care).

79: Gold (Au)

A gold coin, or a piece of gold jewellery, would make a truly wonderful addition to your collection. Alternatively, for under $10, science museums will sell impressive-looking bottles of gold leaf floating in liquid.

82: Lead (Pb)

A fishing sinker is probably the easiest lead object to find.

So there you are. Those could be the first 24 elements in your collection!

Molecules: a book review

Molecules by Theodore Gray

I recently purchased Molecules: The Elements and the Architecture of Everything by Theodore Gray of periodictable.com (this is the sequel to his superb The Elements, which I have previously reviewed). The book is packed with interesting facts about chemistry as it relates to daily life, and the photographs are absolutely beautiful, as this two-page spread shows:

The structure of the book is necessarily a little ad-hoc, lacking the obvious pattern of The Elements. However, it is still well-organised, informative, and compelling. Everyone interested in science should probably have this one on the coffee table too.

I would give this book five stars, except that nothing could be quite as good as The Elements. I should also note that Theodore Gray’s Reactions is coming out soon. I expect that to be worthwhile as well.

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Molecules by Theodore Gray: 4 stars

A sample of elements

  • Helium (He, element 2) – used in balloons, because it is lighter than air
  • Carbon (C, element 6) – one of the key elements in living things
  • Nitrogen (N, element 7) – makes up 78% of the atmosphere
  • Oxygen (O, element 8) – makes up 21% of the atmosphere
  • Aluminium (Al, element 13) – a light metal used to make saucepans and aeroplanes
  • Silicon (Si, element 14) – used to make electronics
  • Phosphorus (P, element 15) – used in elemental form on the side of matchboxes
  • Sulfur (S, element 16) – a widely used element which occurs naturally in elemental form
  • Titanium (Ti, element 22) – a light, strong metal
  • Iron (Fe, element 26) – the most widely used metal (mixed with other elements it becomes steel)
  • Copper (Cu, element 29) – a metal that has been used for about 10,000 years, named after the island of Cyprus
  • Zinc (Zn, element 30) – used in batteries and to prevent corrosion
  • Silver (Ag, element 47) – widely used in jewellery since ancient times (the symbol is from the Latin argentum)
  • Tin (Sn, element 50) – about 5,000 years ago, tin (Latin stannum) was mixed with copper to produce bronze
  • Iodine (I, element 53) – dissolved in alcohol, it is used as a disinfectant
  • Gold (Au, element 79) – widely used in jewellery since ancient times (the symbol is from the Latin aurum)

For more on the elements, see the fantastic book The Elements by Theodore Gray of periodictable.com, which I have previously reviewed.

Chemical Compounds: the board game!

I have previously mentioned my strong interest in science / technology / engineering / mathematics education and in networks and in board games. This has prompted me to start designing educational games, such as the World Solar Challenge game. Joining the collection is my new Chemical Compounds game, which looks like this:

The online game store (faciliated by the wonderful people at The Game Crafter) has a free download link for the rules, should anyone wish to take a look. I also have a few other educational games there.

Element 117 to join the periodic table?

Researchers at the GSI Helmholtz Centre for Heavy Ion Research in Germany have successfully created nuclei of element 117 (Uus), by colliding calcium and berkelium nuclei (see paper and this report). This work confirms earlier reports from Russia.

The periodic table below, from the fantastic periodictable.com website, uses colour-coding to show the half-lives of the unstable elements (click to zoom). For elements 116, 117, and 118 (Uuh, Uus, and Uuo) the half-lives are measured in milliseconds, which casts doubt on the so-called island of stability. It also makes one wonder in what sense these elements can be said to be “discovered.” Still, well done to the GSI Helmholtz team!

The Elements: a book review

The Elements by Theodore Gray

Some time ago, I purchased the photobook The Elements: A Visual Exploration of Every Known Atom in the Universe by Theodore Gray of periodictable.com. A paperback edition has now also become available. Gray’s book is informative, brilliantly designed, and beautifully illustrated, displaying a real passion for the elements. Here are two sample spreads (click to zoom):

Everyone interested in science should probably have this one on the coffee table. Owners of the book can find some online resources here.

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The Elements by Theodore Gray: 5 stars