Samamtha Cornish, of Balclutha Primary School, asks :-

What are chemicals and where do scientists get chemicals from?

David McMorran, a chemist at the University of Otago, responded.

The word Chemical is one that means slightly different things to different people. To many people, a chemical is something that is toxic and harmful to the environment – for this reason, many products which you can buy these days claim to be chemical free. However, these are only one sort of chemical. A chemical is just anything made of atoms, and this means that all ‘stuff’ is made of chemicals – your food, your clothes, your house, even you.

Chemists, scientists who study chemicals and chemical reactions, get their chemicals from various places. Elements are the most basic types of chemicals, ones composed of a single type of atom, and some of these, like carbon, gold and sulphur, can be found in nature. Some chemical compounds, which have more than one type of atom joined together, can also be found in nature – water (H2O) would be an example.

But many other important and useful chemicals cannot be found naturally and so these are made in laboratories using chemical reactions. Chemists sometimes make these themselves, and sometimes they buy them from chemical companies. One American company, called Aldrich, has a catalogue of chemicals that you can buy, which is 3000 pages long!

Many of these chemicals, especially the ones that are used to make things like plastics, are made from simpler compounds which are originally obtained from crude oil. As oil becomes harder to find, and so more expensive, chemists are beginning to look for other places to get these simple compounds from. One possible place is called biomass, which is things like corn cobs, which we normally just throw away but have lots of potentially useful chemical compounds in them. If chemists can work out how to get these compounds out of the corn cobs then we will be less likely to run out of them, since we can always grow more corn!