91É«ÇéƬ

What happens when a hammer hits a nail? Do hammer electrons hit nail electrons? If not, what drives the nail in?

Oliver Howes,

Sydney, Australia

Did abstract mathematics, such as Pythagoras’s theorem, exist before the big bang?

John Woodgate,

Rayleigh, Essex, 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.

91É«ÇéƬ 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.