Why should we be interested in glass?
Dr Anita Zeidler, Physics Department, University of Bath at BRLSI on 30th June 2016.
Convenor science group, John Davies.
Notes by William Gaskell.
Glass’ properties include:
· Good heat shock resistance
· Insulation of heat and electricity
Making it good for cooking hobs.
Slow cooling -> ordered pattern formation -> crystal
Fast cooling (quenching) -> amorphous liquid structure frozen -> glass
Glass is a solid with structure that resembles a liquid. Flint is actually a glass, which is why it could be chiselled into very sharp points for stone age arrowheads and blades.
Glass is composed of silicon and oxygen: Si + O also perhaps B or P, Al, K, Ca, depending on the use. For example, in the nuclear industry glass with a high proportion of lead is used to improve the shielding effect from radiation.
Gorilla glass made by etching or dipping surface of glass into an alkali metal solution, replacing sodium ions with potassium to put the surface under stress making it much harder and more resistant to breaking.
Arctic frog’s blood turns to glass when it freezes so it can survive freezing and defrosting without rupturing any cell membranes or blood vessels as the freezing process to glass would not create any sharp edges as would happen in a regular freezing process where the crystal structure could form sharp spikes which would damage the cell membranes and blood vessels.
Dr Zeidler’s research is on how glass properties change when permanently densified under 20 GPa of pressure, this work was being conducted in Grenoble Research Reactors with neutrons to study how the structure changes.
Caramel, made by dissolving sugar into water, is an example of a glass you can make at home by dissolving sugar in the water then heating it up – let it cool and it caramelises into a glass!