Milk Jug Explodes

Gisborne Herald, Volume LXXIII, Issue 21963, 6 March 1946, Page 6

Milk Jug Explodes

When a large glass milk jug on one of the tables in a Sumner tearoom. Christchurch, suddenly disintegrated with a loud crash on a recent afternoon, the people sitting at the .table could hardly believe thejr eyes, while the proprietress seemed to have even more difficulty in believing their story that the jug had spontaneously shattered itself without being touched. Instances of similar alarming behaviour by articles of mass-produced glassware are no.t, however, uncommon. It results from the too-rapid cooling of the glass after moulding. This sets up powerful internal stresses. A slight scratch on the surface, or, in this case, probably an increase in the strain through the jug of cold milk being placed in the hot sunshine, results in the release of the internal tension, with shattering effect. Wise housewives anneal new glassware by putting i.t in a pot of cold water, bringing it slowly to the boil, and le.l.ting it .cool again as slowly as possible.