Â鶹´«Ã½

Does putting a teaspoon into an open bottle of champagne really prevent it from losing its fizz, and if so, why?

Wolfgang Schady,

Bath, UK

What triggers cicadas to make noises in unison, then go silent periodically?

T. Bard,

Tascott, New South Wales, Australia

To answer this question – or ask a new one – email lastword@newscientist.com.

Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.

Â鶹´«Ã½ retains total…