Investigating elements — introduction
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.
Earth from space
Planet Earth and every thing living on it are made up of elements. The origin of the elements is very much a cosmic affair.
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, 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 conducted at the Large Hadron Collider at CERN in Switzerland 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.
Universal element formation
Elements are formed deep within the cores of certain types of star. Find out more in this interactive.
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.
Use the Large Hadron Collider particle physics research conducted by Dr David Krofcheck as the context for learning about how elements are formed and the structure of the nucleus.
There are several student activities associated with the elements:
Create a photographic periodic table – in this activity, students collect images of everyday objects to represent the elements in the periodic table.
Element rap – in this activity, students become familiar with the names and symbols of the chemical elements by creating a rap or poem.
Symbol find – in this activity, students become familiar with symbols of the chemical elements by creating them using letters from a phrase or sentence.
Atomic clock – use this teacher resource to familiarise students with the names and symbols of the chemical elements.
Elements reacting with oxygen – in this activity students investigate the reaction between copper and oxygen and watch a demonstration of the rapid reaction between hydrogen and oxygen.
The article Elements – weird and wonderful is a lighthearted look at a few of the elements, some we use every day and some that barely exist.
Essential elements
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.
The element iodine
Iodine, a solid at room temperature, is element number 53 on the periodic table. When gently heated it sublimes into a purple vapour as seen here. Iodine is an essential element in the diet, too little can result in the medical condition goitre. Using iodised salt is one way of making it available to the body.
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.
Read about the properties of metals, alloys and metal compounds then use plasticine and sand to make model alloys.
Titanium ring
Titanium has some unique properties. It is lightweight, very strong and tough, corrosion-resistant and, unlike, most other common metals, does not feel cold to the touch. This ring was crafted out of a solid piece of titanium, unlike conventional metal rings that are formed by joining the ends of a piece of metal by soldering or welding.
Isotopes
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.
Isotopes are used for more than carbon dating as explained in the articles Radioisotopes and Using isotopes as tracers.
The student activity Radioactive decay uses coin flips to explore the concepts of half-life and the randomness of radioactive decay.
Question bank
The Investigating elements – question bank provides a list of questions about ceramics and places where their answers can be found. The questions support an inquiry approach.
Key terms
For explanations of key concepts, see Investigating elements – key terms.
Timeline
Explore the timeline to look at some of the early discoveries about the metal titanium.
Te taka pūmotu – the periodic table of elements
Te taka pūmotu – the periodic table of elements lists the atomic number (tua iraho), atomic mass (tau karihi), element symbol (tohu), English names (kupu ingarihi) and Māori names (kupu Māori) for the first 103 elements.
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.
