School pupils from throughout the country are learning more about the surprising world of nanochemistry by creating bright colours in fluids.
A total of 363 senior secondary pupils from 167 schools are attending the University of Otago latest Hands-on at Otago programme this week, to explore future study options at the university.
The pupils work on research projects in the morning, and, in the afternoons, try study ‘‘snacks’’, on a wide range of subjects.
Otago chemistry department outreach co-ordinator Dave Warren said pupils had reacted positively to the chance to undertake experiments with silver nanotechnology this week.
The nano-scale world usually ranges from one nanometre—a millionth of a millimetre— to 100 nanometres.
Larger pieces of silver retained their silver colour, but at nanoparticle size they generated different colours, partly because of their size, and their shape, he said.
Because silver nanoparticle size was about the same of the wavelength of visible light, the particles could absorb colours of the spectrum rather than ‘‘just reflecting it like ‘normal’ silver’’.
The smaller particles absorbed light in the blue end of the spectrum, and so looked red or yellow.
The larger particles absorbed red light, and appeared more blue, he said.
Arnia Bradley, of Invercargill, was yesterday enjoying creating colours at the chemistry department, and said the ‘‘Hands-on at Otago’’ programme was ‘‘really great’’.
She intends to later study health sciences at Otago University.
