Critical Mass: (In nuclear physics K=1) The amount of a substance needed to sustain a chain reaction. An artwork, like many ventures, goes through a complex process of gestation; ideas, sketches, attempts, failures, reappraisals, successes
An exhibition of recent paintings by artist Rupert Whale. Dates: 5 December to 11 January. Location: Cloisters Chambers. Elm Court, 1 Pump Court, Temple, London EC4Y 7AA Private View, Wednesday 5 December, 18:00–20:30.