This is your last chance If you would like to talk on the telephone to the experts, send your name, age and telephone number to: Dial a Scientist, BBC, Broadcasting House, London WIA 1AA.
As usual Paddy Feeny is in the chair and ARTHUR GARRATT is suggesting experiments.
You can talk to the resident scientists, Patrick Moore and Professor Richard Gregory , and to the guest. Professor Eric Laithwaite. This week he will tackle the best questions on any science subject at all. Producer ALISTAIR BROWN