Â鶹´«Ã½

How was rhubarb found to be edible? It certainly isn’t palatable raw.

Donald Windsor,

Norwich, New York, US

Flames go out when their oxygen supply is cut off, so what is happening when you blow a candle out?

Pauline Fothergill,

Pocklington, East Yorkshire, UK

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 editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.

Terms and conditions apply.