From STEWART HIRD
Andrew Deacon’s use of a kitchen microwave oven to produce copper sulphate
crystals has produced an interesting result that has nothing to do with
microwaves (Letters, 15 February and 7 March).
The growth of copper sulphate or any other crystals from saturated solutions
is governed by the rate of cooling of the hot solution and also by the stability
of the external air temperature. Perfectly formed large crystals grow when
saturated solutions cool very slowly at constant temperatures. A microwave
oven provides an ideal environment.
Stewart Hird Aldershot, Hampshire
