The term originated : "When K. Eric Drexler popularized the word 'nanotechnology' in the 1980's, he was talking about building machines on the scale of molecules, a few nanometres wideâ€"motors, robot arms, and even whole computers, far smaller than a cell." crnano.org/whatis.htm
Why 'nano'?
Scientists find it convenient to use abbreviations so that they don't waste time writing down more than they need to; and so they can communicate with other scientists who may speak a different language. We all do this every day: there is a SIM in our mobile phone; and we use ATMs and have PINs to access them; and we know what the icons on the computer are, even if the 'phone' icon doesn't look anything like the phone we use now.
In science, over many years, the formal system of symbols denoting quantities is called the SI - Systeme Internationale – set of symbols.
Under this convention, the prefix 'nano' has the abbreviated symbol n (always lower case) and it means something divided by 10 a total of nine times. This is denoted mathematically as 10-9 (pronounced 'ten-to-the-minus-nine').
The word 'nano' comes from the Greek word meaning 'dwarf', but it also has connotations of the number nine because in Latin, the word for 9 is 'novem' (November used to be the ninth month), abbreviated to 'nonus' or 'non' when used as a prefix. en.wikipedia.org/wiki/Nano-
Note: When a billion is not a billion – an international discrepency
The American billion is 109 (something multiplied by 10 a total of nine times, or one thousand times one million), but an English billion is a million times a million, which is 1012. So it is easier to be a billionaire in America than in England. You will sometimes read that 'nano' is 'one billionth of a metre', which it would be in America but not in England.
This description of an amount is very difficult to imagine, and I don't find it helpful in describing how small things are. For these reasons, as well as the international confusion, I will not refer to 'billion' again in this article.
Let's try to get our heads around the very large and very small.
Sometimes it is easier to grasp a concept by imagining the very big, rather than the very small. So let's start by imagining 1 million kilometres (106 km).
If you drive or cycle or walk 1 km, you know how far that is. If you multiply this by 10, you get 101 – or 10 km. You can imagine that too. Now multiply 10 again and you get 100 (102 two zeros). By this time you are probably thinking of driving or going by train, or even a plane. Now do this again and you get 1000 km (three zeros, and yes you guessed, denoted 103).
This is approximately the distance between Melbourne and Sydney, or Sydney and Brisbane. If we keep doing this imaginary 'multiplying by 10' three more times - remember we are multiplying by ten each time, not merely adding ten - we get 1 million kilometres (1,000,000 km with six zeros) or 106. This will take you well outside the Earth – further than twice the distance of the Moon from the Earth. See how quickly the distances get much bigger when we multiply each time?
Now try to reverse the process in your mind and go stepwise to the very tiny; this time dividing into tenths each time. Remember, we are doing the reverse and every time we do a division the amount gets much, much smaller, smaller than if we were just subtracting an amount.
Imagine the length of one large step, 1 metre, and divide it by ten, then divide by ten again to get 100th, which is one cm (centimtre). Imagine dividing this into tenths again to get 1 mm (millimetre – a thousanth of a metre) and so on until you have divided these vanishingly small quantities by 10 a total of nine times. This will get you to one millionth of a millimetre, which is a nanometre (nm).
In scientific notation, when you divide instead of multiply by ten each time, you use a minus sign to show you are getting smaller and smaller. Therefore 1 cm = 10-2 m ('ten-to-the-minus-two-metres') and 1 nm = 10-9 m, as mentioned above.
This is the scale of 'nanotechnology' and 'nanomaterials'.
Even so, we are not yet quite at the atomic scale. Atoms are measured in Ã…ngstroms named after a Swedish chemist. 1 Ã…ngstrom (Ã…) = 0.1 nm (one-tenth of a nanometre) Large atoms such as sulfur (S) or chlorine (Cl) are approximately 1Ã… in diameter; so a molecule containing 10 atoms of this size would be about 1 nm (nanometre) across.
If they are so small, how are nanomaterials 'seen'?
In order for us to see something with our eyes, the rays of light have to bounce off the object and back to our eyes. If the object is very small, then we can use a microscope with a set of magnifying lenses and mirrors to reflect the light. But we still use light.
The wavelengths of visible light range from 400 nm (nanometres, as explained above) for red light to 700 nm (violet light). So because nanomaterials and individual molecules are smaller than the wavelength of these waves of light, we cannot see them using light microscopes, and we cannot 'see' them using our normal visual apparatus in our eye.
However, before nanotechnology had reached its current state of knowledge (as early as 1931), microscopes using beams of electrons with wavelengths 100,000 times smaller than light rays had already been developed and were in use in many areas of science. These electron microscopes can be used, after appropriate preparation of the samples, to make images of nanomaterials. They have to be coupled with software to interpret the signals and make a computer-enhanced image that makes sense to our eyes. http://en.wikipedia.org/wiki/Electron_microscope
en.wikipedia.org/wiki/Electron_microscope
There are other ways, too, of characterising various aspects of nanomaterials. These have been used in chemistry to investigate molecules and atoms. One of them is mass spectrometry where a small amount of the material to be studied is bombarded by electrical pulses to break it into even smaller fragments, and these are caught by another electromagnetic detector and the mass ('weight') of the individual parts can be calculated.
A few innovative uses of nanotechnology
A very few of the many, many uses of nanoparticles are outlined below:
• A single atomic layer of tin can be deposited on surfaces to increase electrical conductivity www.sciencedaily.com/releases/2013/11/131121135635.htm
• Chemical 'sponges' made of nanoparticles can speed up useful reactions, and help scientists visualise these materials using X-ray beams www.sciencedaily.com/releases/2013/11/131112123852.htm
• Some materials can be engineered to be 'self-soldering' if they start to break www.sciencedaily.com/releases/2013/11/131125164820.htm
• there are many studies where nanomaterials are being used in combination with natural biological materials – in this case to introduce medications into the body like a new type of vaccine. www.eurekalert.org/pub_releases/2013-12/uoc--vf112613.php
Safety issues with nanomaterials.
Because nanoparticles are small enough to get inside our cells scientists and regulatory authorities are already looking at how to use these useful materials safely. You may have heard a recent court case and general controversy about whether or not some sunscreens contained what was defined as 'nanoparticles', because the definition had changed – and if so whether or not they were harmful.
According to a recent article in 'Chemistry in Australia' magazine (July 2013, p.6), a recent pair of reports has been released by Safe Work Australia, advocating caution in the use and manufacture of these materials. These are only part of a "comprehensive program of work on nanotechnology safety management, which began in 2007" according to the Chairwoman, Ms Ann Sherry. .
www.raci.org.au/flipbook#page=3
Hopefully, we have learnt from history where we have discovered later that things like soot from coal fires, emissions from leaded petrol, asbestos and many others were harmful over a long period. It is a positive step to see that, at least the potential hazards are being discussed, and ways of safely using these new materials are being carefully considered.
Matthew 13 verses 31-32: "He told them another parable; 'The kingdom of heaven is like a mustard seed, which a man took and planted in his field. Though it is the smallest of all your seeds, yet when it grows, it is the largest of garden plants and becomes a tree, so that the birds of the air come and perch in its branches' ".
Dr Mark Tronson is a Baptist minister (retired) who served as the Australian cricket team chaplain for 17 years (2000 ret) and established Life After Cricket in 2001. He was recognised by the Olympic Ministry Medal in 2009 presented by Carl Lewis Olympian of the Century. He has written 24 books, and enjoys writing. He is married to Delma, with four adult children and grand-children.
Dr Mark Tronson's archive of articles can be viewed at
www.pressserviceinternational.org/mark-tronson.html
