Planet Earth and every thing living on it is made up of elements. An element is a pure substance made up of atoms all of the same type. Some elements are vital to our survival, while others – depending on the dose – are harmful to us.
So where did elements come from? How are elements classified? What uses have we found for elements in our modern society? These resources may be able to provide answers to these questions.
Where did elements come from?
Here’s what Martin Rees, UK’s Astronomer Royal, recently said:
And we know that every atom in our body was forged in an ancient star somewhere in the Milky Way. We are literally the ashes of long-dead stars – the nuclear waste from the fuel that makes stars shine. To understand ourselves, we must understand the atoms we’re made of – but we must also understand the stars that made those atoms.
The experiments that will be conducted at the Large Hadron Collider at CERN in Switzerland will allow scientists to better understand the fine structure of atoms and explore the conditions that are thought to have existed at the moment of creation of the universe.
Arranging the elements
The periodic table of elements is a very useful tool, and it can be used to organise many of the ideas in chemistry. The development of the periodic table is a fascinating story, demonstrating the roles that imagination and creativity play in science. The search for new elements continues at many research labs around the world.
There are several student activities associated with the elements: Element rap, Symbol find and Atomic clock use creative approaches to familiarise the names and symbols of chemical elements. Elements reacting with oxygen is a practical activity.
Which elements are we humans made up of? Does our diet provide us with all the elements we need? What happens if we have too much or too little of a given element? The article The essential elements provides answers to these intriguing questions.
Uses of metals
Of the 92 naturally occurring elements, 78 are metals. Our modern society is literally built with metals. But forget iron and aluminium – titanium is the metal of the future, with titanium alloys increasingly being used in transport, medical science and high-tech sports. Dr Brian Gabbitas and Professor Deliang Zhang are two of the scientists involved with the production of titanium-based alloys.
Most elements consist of atoms having several different mass numbers. Atoms with the same atomic number but a different mass number are called isotopes.
Isotopes, particularly those that are radioactive, are widely used in our modern society. Perhaps the best known of these is carbon-14, which was used by Dr Fiona Petchey to date artefacts of historical importance in an archaeological dig at the Wairau Bar close to the town of Blenheim.
The student activity Radioactive decay uses coin flips to explore the concepts of half-life and the randomness of radioactive decay.
For explanations of key concepts, see Investigating elements – key terms.
Nature of science
Science knowledge is reliable and durable but never absolute or certain. This knowledge is subject to change. Scientific claims change as new evidence – made possible by advances in thinking and technology – is brought to bear on these claims.