QUESTIONS

Q: How do we know there is an absolute zero? Has it ever been achieved in a laboratory?

Peter Cox, Maidenhead, Berks. Q: In the mid-Seventies when I worked in Iraq, outside the entrance to Baghdad railway station was a Derby-built steam locomotive. Is it still there?

N. Cuss, Swindon, Wilts. Q: As a child, when I had a nosebleed I was told to lean my head back and pinch the top of my nose. I have since been told that this was the wrong thing to do. Which is correct?

Janet Morris, twickenham, Middx.